Emerging as a new class of two-dimensional materials with atomically thin layers, MBenes have great potential for many important applications such as energy storage and electrocatalysis. Toward mitigating carbon footprint, there has been increasing interest in CO2/CO conversion on MBenes, but mostly focused on C1 products. C2+ chemicals generally possess higher energy densities and wider applications than C1 counterparts. However, C–C coupling is technically challenging because of high energy requirement and currently few catalysts are suited for this process. Here, we explore electrochemical CO reduction reaction to C2 chemicals on Mo2B2O2 MBene via density-functional theory calculations. Remarkably, the most favorable CO–COH coupling is revealed to be a spontaneous and barrierless process, making Mo2B2O2 an efficient catalyst for C–C coupling. Among C1 and C2 chemicals, ethanol is predicted to be the primary product. Furthermore, by charge and bond analysis, it is unraveled that there exist significantly more unbonded electrons in the C atom of intermediate *COH than other C1 intermediates, which is responsible for the facile C–C coupling. From an atomic scale, this work provides microscopic insight into C–C coupling process and suggests Mo2B2O2 a promising catalyst for electrochemical CO reduction to C2 chemicals.
Enhancing the lifetime of perovskite solar cells (PSCs) is one of the essential challenges for their industrialization. Although the external encapsulation protects the perovskite device from the erosion of moisture and oxygen under various harsh conditions. However, the perovskite devices still undergo static and dynamic thermal stress during thermal and thermal cycling aging, respectively, resulting in irreversible damage to the morphology, component, and phase of stacked materials. Herein, the viscoelastic polymer polyvinyl butyral (PVB) material is designed onto the surface of perovskite films to form flexible interface encapsulation. After PVB interface encapsulation, the surface modulus of perovskite films decreases by nearly 50%, and the interface stress range under the dynamic temperature field (−40 to 85 °C) drops from −42.5 to 64.8 MPa to −14.8 to 5.0 MPa. Besides, PVB forms chemical interactions with FA+ cations and Pb2+, and the macroscopic residual stress is regulated and defects are reduced of the PVB encapsulated perovskite film. As a result, the optimized device’s efficiency increases from 22.21% to 23.11%. Additionally, after 1500 h of thermal treatment (85 °C), 1000 h of damp heat test (85 °C & 85% RH), and 250 cycles of thermal cycling test (−40 to 85 °C), the devices maintain 92.6%, 85.8%, and 96.1% of their initial efficiencies, respectively.
In this article, we report a 3D NiFe phosphite oxyhydroxide plastic electrode using high-resolution digital light processing (DLP) 3D-printing technology via induced chemical deposition method. The as-prepared 3D plastic electrode exhibits no template requirement, freedom design, low-cost, robust, anticorrosion, lightweight, and micro-nano porous characteristics. It can be drawn to the conclusion that highly oriented open-porous 3D geometry structure will be beneficial for improving surface catalytic active area, wetting performance, and reaction–diffusion dynamics of plastic electrodes for oxygen evolution reaction (OER) catalysis process. Density functional theory (DFT) calculation interprets the origin of high activity of NiFe(PO3)O(OH) and demonstrates that the implantation of the –PO3 can effectively bind the 3d orbital of Ni in NiFe(PO3)O(OH), lead to the weak adsorption of intermediate, make electron more active to improve the conductivity, thereby lowing the transform free energy of *O to *OOH. The water oxidization performance of as-prepared 3D NiFe(PO3)O(OH) hollow tubular (HT) lattice plastic electrode has almost reached the state-of-the-art level compared with the as-reported large-current-density catalysts or 3D additive manufactured plastic/metal-based electrodes, especially for high current OER electrodes. This work breaks through the bottleneck that plagues the performance improvement of low-cost high-current electrodes.
Next-generation Li-ion batteries are expected to exhibit superior energy and power density, along with extended cycle life. Ni-rich high-capacity layered nickel manganese cobalt oxide electrode materials (NMC) hold promise in achieving these objectives, despite facing challenges such as capacity fade due to various degradation modes. Crack formation within NMC-based cathode secondary particles, leading to parasitic reactions and the formation of inactive crystal structures, is a critical degradation mechanism. Mechanical and chemical degradation further deteriorate capacity and lifetime. To mitigate these issues, an artificial cathode electrolyte interphase can be applied to the active material before battery cycling. While atomic layer deposition (ALD) has been extensively explored for active material coatings, molecular layer deposition (MLD) offers a complementary approach. When combined with ALD, MLD enables the deposition of flexible hybrid coatings that can accommodate electrode material volume changes during battery operation. This study focuses on depositing TiO2-titanium terephthalate thin films on a LiNi0.8Mn0.1Co0.1O2 electrode via ALD-MLD. The electrochemical evaluation demonstrates favorable lithium-ion kinetics and reduced electrolyte decomposition. Overall, the films deposited through ALD-MLD exhibit promising features as flexible and protective coatings for high-energy lithium-ion battery electrodes, offering potential contributions to the enhancement of advanced battery technologies and supporting the growth of the EV and stationary battery industries.
The demand for electronic devices that utilize lithium is steadily increasing in this rapidly advancing technological world. Obtaining high-purity lithium in an environmentally friendly way is challenging by using commercialized methods. Herein, we propose the first fuel cell system for continuous lithium-ion extraction using a lithium superionic conductor membrane and advanced electrode. The fuel cell system for extracting lithium-ion has demonstrated a twofold increase in the selectivity of Li+/Na+ while producing electricity. Our data show that the fuel cell with a titania-coated electrode achieves 95% lithium-ion purity while generating 10.23 Wh of energy per gram of lithium. Our investigation revealed that using atomic layer deposition improved the electrode’s uniformity, stability, and electrocatalytic activity. After 2000 cycles determined by cyclic voltammetry, the electrode preserved its stability.
Machine learning (ML) integrated with density functional theory (DFT) calculations have recently been used to accelerate the design and discovery of single-atom catalysts (SACs) by establishing deep structure–activity relationships. The traditional ML models are always difficult to identify the structural differences among the single-atom systems with different modification methods, leading to the limitation of the potential application range. Aiming to the structural properties of several typical two-dimensional MA2Z4-based single-atom systems (bare MA2Z4 and metal single-atom doped/supported MA2Z4), an improved crystal graph convolutional neural network (CGCNN) classification model was employed, instead of the traditional machine learning regression model, to address the challenge of incompatibility in the studied systems. The CGCNN model was optimized using crystal graph representation in which the geometric configuration was divided into active layer, surface layer, and bulk layer (ASB-GCNN). Through ML and DFT calculations, five potential single-atom hydrogen evolution reaction (HER) catalysts were screened from chemical space of 600 MA2Z4-based materials, especially V1/HfSn2N4(S) with high stability and activity (ΔGH* is 0.06 eV). Further projected density of states (pDOS) analysis in combination with the wave function analysis of the SAC-H bond revealed that the SAC-dz2 orbital coincided with the H-s orbital around the energy level of −2.50 eV, and orbital analysis confirmed the formation of σ bonds. This study provides an efficient multistep screening design framework of metal single-atom catalyst for HER systems with similar two-dimensional supports but different geometric configurations.
With the widespread use of lithium-ion batteries in electric vehicles, energy storage, and mobile terminals, there is an urgent need to develop cathode materials with specific properties. However, existing material control synthesis routes based on repetitive experiments are often costly and inefficient, which is unsuitable for the broader application of novel materials. The development of machine learning and its combination with materials design offers a potential pathway for optimizing materials. Here, we present a design synthesis paradigm for developing high energy Ni-rich cathodes with thermal/kinetic simulation and propose a coupled image-morphology machine learning model. The paradigm can accurately predict the reaction conditions required for synthesizing cathode precursors with specific morphologies, helping to shorten the experimental duration and costs. After the model-guided design synthesis, cathode materials with different morphological characteristics can be obtained, and the best shows a high discharge capacity of 206 mAh g−1 at 0.1C and 83% capacity retention after 200 cycles. This work provides guidance for designing cathode materials for lithium-ion batteries, which may point the way to a fast and cost-effective direction for controlling the morphology of all types of particles.
The intense research of lithium-ion batteries has been motivated by their successful applications in mobile devices and electronic vehicles. The emerging of intelligent control in kinds of devices brings new requirements for battery systems. The high-energy lithium batteries are expected to respond or react under different environmental conditions. In this work, a tri-salt composite electrolyte is designed with a temperature switch function for intelligently temperature-controlled lithium batteries. Specifically, the halide Li3YBr6 together with LiTFSI and LiNO3 works as active fillers in a low-melting-point polymer matrix (polyethyleneglycol dimethyl ether (PEGDME) and polyethylene oxide (PEO)), which is further filled into the pre-lithiated alumina fiber skeleton. Above 60 °C, the composite electrolyte exists in the liquid state and fully contacts with the working electrodes on the liquid–solid interface, effectively minimizing the interfacial resistance and leading to high discharge capacity in the cell. The electrolyte is changed into a solid state below 30 °C so that the ionic conductivity is significantly reduced and the interface resistance is increased dramatically on the solid–solid interface. Therefore, by simply adjusting the temperature, the cell can be turned “ON” or “OFF” intentionally. This novel function of the composite electrolyte has enlightening significance in developing intelligently temperature-controlled lithium batteries.
Lithium metal batteries (LMBs) are considered the ideal choice for high volumetric energy density lithium-ion batteries, but uncontrolled lithium deposition poses a significant challenge to the stability of such devices. In this paper, we introduce a 2.5 µm-thick asymmetric and ultrastrong separator, which can induce tissue-like lithium deposits. The asymmetric separator, denoted by utPE@Cu2O, was prepared by selective synthesis of Cu2O nanoparticles on one of the outer surfaces of a nanofibrous (diameter ∼10 nm) ultrastrong ultrahigh molecular weight polyethylene (UHMWPE) membrane. Microscopic analysis shows that the lithium deposits have tissue-like morphology, resulting in the symmetric lithium cells assembled using utPE@Cu2O with symmetric Cu2O coating exhibiting stable performance for over 2000 h of cycling. This work demonstrates the feasibility of a facile approach ultrathin separators for the deployment of lithium metal batteries, providing a pathway towards enhanced battery performance and safety.
Transition metal phosphides (TMPs) have emerged as an alternative to precious metals as efficient and low-cost catalysts for water electrolysis. Elemental doping and morphology control are effective approaches to further improve the performance of TMPs. Herein, Fe-doped CoP nanoframes (Fe-CoP NFs) with specific open cage configuration were designed and synthesized. The unique nano-framework structured Fe-CoP material shows overpotentials of only 255 and 122 mV at 10 mA cm-2 for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively, overwhelming most transition metal phosphides. For overall water splitting, the cell voltage is 1.65 V for Fe-CoP NFs at a current density of 10 mA cm−2, much superior to what is observed for the classical nanocubic structures. Fe-CoP NFs show no activity degradation up to 100 h which contrasts sharply with the rapidly decaying performance of noble metal catalyst reference. The superior electrocatalytic performance of Fe-CoP NFs due to abundant accessible active sites, reduced kinetic energy barrier, and preferable *O-containing intermediate adsorption is demonstrated through experimental observations and theoretical calculations. Our findings could provide a potential method for the preparation of multifunctional material with hollow structures and offer more hopeful prospects for obtaining efficient earth-abundant catalysts for water splitting.
The capture, regeneration, and conversion of CO2 from ambient air and flue gas streams are critical aspects of mitigating global warming. Solid sorbents for CO2 absorption are very promising as they have high mass transfer areas without energy input and reduce emissions and minimize corrosion as compared to liquid sorbents. However, precisely tunable solid CO2 sorbents are difficult to produce. Here, we demonstrate the high-throughput production of hydrogel-based CO2-absorbing particles via liquid jetting. By wrapping a liquid jet consisting of an aqueous solution of cross-linkable branched polyethylenimine (PEI) with a layer of suspension containing hydrophobic silica nanoparticles, monodisperse droplets with a silica nanoparticle coating layer was formed in the air. A stable Pickering emulsion containing PEI droplets was obtained after these ejected droplets were collected in a heated oil bath. The droplets turn into mm-sized particles after thermal curing in the bath. The diameter, PEI content, and silica content of the particles were systematically varied, and their CO2 absorption was measured as a function of time. Steam regeneration of the particles enabled cyclic testing, revealing a CO2 absorption capacity of 6.5 ± 0.5 mol kg−1 solid PEI in pure CO2 environments and 0.7 ± 0.3 mol kg−1 solid PEI for direct air capture. Several thousands of particles were produced per second at a rate of around 0.5 kg per hour, with a single nozzle. This process can be further scaled by parallelization. The complete toolbox for the design, fabrication, testing, and regeneration of functional hydrogel particles provides a powerful route toward novel solid sorbents for regenerative CO2 capture.
While lithium resources are scarce for high energy-dense lithium-ion batteries (LIBs), sodium-ion batteries (SIBs), serving as an alternative, inherently suffer from low capacity and the high-cost use of non-graphite anodes. Combining Li- and Na-ions within a single battery system is expected to mitigate the shortcomings of both systems while leveraging their respective advantages. In this study, we developed and assembled a nanodiamonds (NDs)-assisted co-Li/Na-ion battery (ND–LSIB). This innovative battery system comprised a commercial graphite anode, an ND-modified polypropylene (DPP) separator, a hybrid lithium/sodium-based electrolyte, and a cathode. It is theoretically and experimentally demonstrated that the ND/Li co-insertion can serve as an ion-drill opening graphite layers and reconstructing graphite anodes into few-layered graphene with expanding interlayer space, achieving highly efficient Li/Na storage and the theoretical maximum of LiC6 for Li storage in graphite. In addition, ND is helpful for creating a LiF-/NaF-rich hybrid solid electrolyte interface with improved ionic mobility, mechanical strength, and reversibility. Consequently, ND–LSIBs have higher specific capacities ∼1.4 times the theoretical value of LIBs and show long-term cycling stability. This study proposes and realizes the concept of Li/Na co-storage in one ion battery with compatible high-performance, cost-effectiveness, and industrial prospects.
The development of portable X-ray detectors is necessary for diagnosing fractures in unconscious patients in emergency situations. However, this is quite challenging because of the heavy weight of the scintillator and silicon photodetectors. The weight and thickness of X-ray detectors can be reduced by replacing the silicon layer with an organic photodetectors. This study presents a novel bithienopyrroledione-based polymer donor that exhibits excellent photodetection properties even in a thick photoactive layer (∼700 nm), owing to the symmetric backbone and highly soluble molecular structure of bithienopyrroledione. The ability of bithienopyrroledione-based polymer donor to strongly suppress the dark current density (Jd ∼ 10−10 A cm−2) at a negative bias (−2.0 V) while maintaining high responsivity (R = 0.29 A W−1) even at a thickness of 700 nm results in a maximum shot-noise-limited specific detectivity of Dsh* = 2.18 × 1013 Jones in the organic photodetectors. Printed organic photodetectors are developed by slot-die coating for use in X-ray detectors, which exhibit Dsh* = 2.73 × 1012 Jones with clear rising (0.26 s) and falling (0.29 s) response times upon X-ray irradiation. Detection reliability is also proven by linear response of the X-ray detector, and the X-ray detection limit is 3 mA.
This work demonstrates a novel polymerization-derived polymer electrolyte consisting of methyl methacrylate, lithium bis(trifluoromethanesulfonyl)imide and fluoroethylene carbonate. The polymerization of MMA was initiated by the amino compounds following an anionic catalytic mechanism. LiTFSI plays both roles including the initiator and Li ion source in the polymer electrolyte. Normally, lithium bis(trifluoromethanesulfonyl)imide has difficulty in initiating the polymerization reaction of methyl methacrylate monomer, a very high concentration of lithium bis(trifluoromethanesulfonyl)imide is needed for initiating the polymerization. However, the fluoroethylene carbonate additive can work as a supporter to facilitate the degree of dissociation of lithium bis(trifluoromethanesulfonyl)imide and increase its initiator capacity due to the high dielectric constant. The as-prepared poly-methyl methacrylate-based polymer electrolyte has a high ionic conductivity (1.19 × 10−3 S cm−1), a wide electrochemical stability window (5 V vs Li+/Li), and a high Li ion transference number (tLi+) of 0.74 at room temperature (RT). Moreover, this polymerization-derived polymer electrolyte can effectively work as an artificial protective layer on Li metal anode, which enabled the Li symmetric cell to achieve a long-term cycling performance at 0.2 mAh cm−2 for 2800 h. The LiFePO4 battery with polymerization-derived polymer electrolyte-modified Li metal anode shows a capacity retention of 91.17% after 800 cycles at 0.5 C. This work provides a facile and accessible approach to manufacturing poly-methyl methacrylate-based polymerization-derived polymer electrolyte and shows great potential as an interphase in Li metal batteries.
All-solid-state lithium metal batteries (ASSLMBs) featuring sulfide solid electrolytes (SEs) are recognized as the most promising next-generation energy storage technology because of their exceptional safety and much-improved energy density. However, lithium dendrite growth in sulfide SEs and their poor air stability have posed significant obstacles to the advancement of sulfide-based ASSLMBs. Here, a thin layer (approximately 5 nm) of g-C3N4 is coated on the surface of a sulfide SE (Li6PS5Cl), which not only lowers the electronic conductivity of Li6PS5Cl but also achieves remarkable interface stability by facilitating the in situ formation of ion-conductive Li3N at the Li/Li6PS5Cl interface. Additionally, the g-C3N4 coating on the surface can substantially reduce the formation of H2S when Li6PS5Cl is exposed to humid air. As a result, Li–Li symmetrical cells using g-C3N4-coated Li6PS5Cl stably cycle for 1000 h with a current density of 0.2 mA cm−2. ASSLMBs paired with LiNbO3-coated LiNi0.6Mn0.2Co0.2O2 exhibit a capacity of 132.8 mAh g−1 at 0.1 C and a high-capacity retention of 99.1% after 200 cycles. Furthermore, g-C3N4-coated Li6PS5Cl effectively mitigates the self-discharge behavior observed in ASSLMBs. This surface-coating approach for sulfide solid electrolytes opens the door to the practical implementation of sulfide-based ASSLMBs.
α-Keggin polyoxometalates (POMs) [XW12O40]n− (X = Al, Si, P, S) are widely used in batteries owing to their remarkable redox activity. However, the mechanism underlying the applications appears inconsistent with the widely accepted covalent bonding nature. Here, first-principles calculations show that XW12 are core–shell structures composed of a shell and an XO4n− core, both are stabilized by covalent interactions. Interestingly, owing to the presence of a substantial number of electrons in W12O36 shell, the frontier molecular orbitals of XW12 are not only strongly delocalized but also exhibit superatomic properties with high-angular momentum electrons that do not conform to the Jellium model. Detailed analysis indicates that energetically high lying filled molecular orbitals (MOs) have reached unusually high-angular momentum characterized by quantum number K or higher, allowing for the accommodation of numerous electrons. This attribute confers strong electron acceptor ability and redox activity to XW12. Moreover, electrons added to XW12 still occupy the K orbitals and will not cause rearrangement of the MOs, thereby maintaining the stability of these structures. Our findings highlight the structure–activity relationship and provide a direction for tailor-made POMs with specific properties at atomic level.
The structure–property relationship at interfaces is difficult to probe for thermoelectric materials with a complex interfacial microstructure. Designing thermoelectric materials with a simple, structurally-uniform interface provides a facile way to understand how these interfaces influence the transport properties. Here, we synthesized Bi2–xSbxTe3 (x = 0, 0.1, 0.2, 0.4) nanoflakes using a hydrothermal method, and prepared Bi2–xSbxTe3 thin films with predominantly (0001) interfaces by stacking the nanoflakes through spin coating. The influence of the annealing temperature and Sb content on the (0001) interface structure was systematically investigated at atomic scale using aberration-corrected scanning transmission electron microscopy. Annealing and Sb doping facilitate atom diffusion and migration between adjacent nanoflakes along the (0001) interface. As such it enhances interfacial connectivity and improves the electrical transport properties. Interfac reactions create new interfaces that increase the scattering and the Seebeck coefficient. Due to the simultaneous optimization of electrical conductivity and Seebeck coefficient, the maximum power factor of the Bi1.8Sb0.2Te3 nanoflake films reaches 1.72 mW m−1 K−2, which is 43% higher than that of a pure Bi2Te3 thin film.
Thermally chargeable supercapacitors can collect low-grade heat generated by the human body and convert it into electricity as a power supply unit for wearable electronics. However, the low Seebeck coefficient and heat-to-electricity conversion efficiency hinder further application. In this paper, we designed a high-performance thermally chargeable supercapacitor device composed of ZnMn2O4@Ti3C2Tx MXene composites (ZMO@Ti3C2Tx MXene) electrode and UIO-66 metal–organic framework doped multichannel polyvinylidene fluoridehexafluoro-propylene ionogel electrolyte, which realized the thermoelectric conversion and electrical energy storage at the same time. This thermally chargeable supercapacitor device exhibited a high Seebeck coefficient of 55.4 mV K−1, thermal voltage of 243 mV, and outstanding heat-to-electricity conversion efficiency of up to 6.48% at the temperature difference of 4.4 K. In addition, this device showed excellent charge–discharge cycling stability at high-temperature differences (3 K) and low-temperature differences (1 K), respectively. Connecting two thermally chargeable supercapacitor units in series, the generated output voltage of 500 mV further confirmed the stability of devices. When a single device was worn on the arm, a thermal voltage of 208.3 mV was obtained indicating the possibility of application in wearable electronics.
Lithium-sulfur batteries are emerging as sustainable replacements for current lithium-ion batteries. The commercial viability of this novel type of battery is still under debate due to the extensive use of highly reactive lithium-metal anodes and the complex electrochemistry of the sulfur cathode. In this research, a novel sulfur-based battery has been proposed that eliminates the need for metallic lithium anodes and other critical raw materials like cobalt and graphite, replacing them with biomass-derived materials. This approach presents numerous benefits, encompassing ample availability, cost-effectiveness, safety, and environmental friendliness. In particular, two types of biochar-based anode electrodes (non-activated and activated biochar) derived from spent common ivy have been investigated as alternatives to metallic lithium. We compared their structural and electrochemical properties, both of which exhibited good compatibility with the typical electrolytes used in sulfur batteries. Surprisingly, while steam activation results in an increased specific surface area, the non-activated ivy biochar demonstrates better performance than the activated biochar, achieving a stable capacity of 400 mA h g−1 at 0.1 A g−1 and a long lifespan (>400 cycles at 0.5 A g−1). Our results demonstrate that the presence of heteroatoms, such as oxygen and nitrogen positively affects the capacity and cycling performance of the electrodes. This led to increased d-spacing in the graphitic layer, a strong interaction with the solid electrolyte interphase layer, and improved ion transportation. Finally, the non-activated biochar was successfully coupled with a sulfur cathode to fabricate lithium-metal-free sulfur batteries, delivering a specific energy density of ∼600 Wh kg−1.
Due to the push for carbon neutrality in various human activities, the development of methods for producing electricity without relying on chemical reaction processes or heat sources has become highly significant. Also, the challenge lies in achieving microwatt-scale outputs due to the inherent conductivity of the materials and diverting electric currents. To address this challenge, our research has concentrated on utilizing nonconductive mediums for water-based low-cost microfibrous ceramic wools in conjunction with a NaCl aqueous solution for power generation. The main source of electricity originates from the directed movement of water molecules and surface ions through densely packed microfibrous ceramic wools due to the effect of dynamic electric double layer. This occurrence bears resemblance to the natural water transpiration in plants, thereby presenting a fresh and straightforward approach for producing electricity in an ecofriendly manner. The generator module demonstrated in this study, measuring 12 × 6 cm2, exhibited a noteworthy open-circuit voltage of 0.35 V, coupled with a short-circuit current of 0.51 mA. Such low-cost ceramic wools are suitable for ubiquitous, permanent energy sources and hold potential for use as self-powered sensors and systems, eliminating the requirement for external energy sources such as sunlight or heat.
Epoxy resin, characterized by prominent mechanical and electric-insulation properties, is the preferred material for packaging power electronic devices. Unfortunately, the efficient recycling and reuse of epoxy materials with thermally cross-linked molecular structures has become a daunting challenge. Here, we propose an economical and operable recycling strategy to regenerate waste epoxy resin into a high-performance material. Different particle size of waste epoxy micro-spheres (100–600 µm) with core-shell structure is obtained through simple mechanical crushing and boron nitride surface treatment. By using smattering epoxy monomer as an adhesive, an eco-friendly composite material with a “brick-wall structure” can be formed. The continuous boron nitride pathway with efficient thermal conductivity endows eco-friendly composite materials with a preeminent thermal conductivity of 3.71 W m−1 K−1 at a low content of 8.5 vol% h-BN, superior to pure epoxy resin (0.21 W m−1 K−1). The composite, after secondary recycling and reuse, still maintains a thermal conductivity of 2.12 W m−1 K−1 and has mechanical and insulation properties comparable to the new epoxy resin (energy storage modulus of 2326.3 MPa and breakdown strength of 40.18 kV mm−1). This strategy expands the sustainable application prospects of thermosetting polymers, offering extremely high economic and environmental value.
Air quality is deteriorating due to continuing urbanization and industrialization. In particular, nitrogen dioxide (NO2) is a biologically and environmentally hazardous byproduct from fuel combustion that is ubiquitous in urban life. To address this issue, we report a high-performance flexible indium phosphide nanomembrane NO2 sensor for real-time air quality monitoring. An ultralow limit of detection of ∼200 ppt and a fast response have been achieved with this device by optimizing the film thickness and doping concentration during indium phosphide epitaxy. By varying the film thickness, a dynamic range of values for NO2 detection from parts per trillion (ppt) to parts per million (ppm) level have also been demonstrated under low bias voltage and at room temperature without additional light activation. Flexibility measurements show an adequately stable response after repeated bending. On-site testing of the sensor in a residential kitchen shows that NO2 concentration from the gas stove emission could exceed the NO2 Time Weighted Average limit, i.e., 200 ppb, highlighting the significance of real-time monitoring. Critically, the indium phosphide nanomembrane sensor element cost is estimated at <0.1 US$ due to the miniatured size, nanoscale thickness, and ease of fabrication. With these superior performance characteristics, low cost, and real-world applicability, our indium phosphide nanomembrane sensors offer a promising solution for a variety of air quality monitoring applications.
We employ advanced first principles methodology, merging self-consistent phonon theory and the Boltzmann transport equation, to comprehensively explore the thermal transport and thermoelectric properties of KCdAs. Notably, the study accounts for the impact of quartic anharmonicity on phonon group velocities in the pursuit of lattice thermal conductivity and investigates 3ph and 4ph scattering processes on phonon lifetimes. Through various methodologies, including examining atomic vibrational modes and analyzing 3ph and 4ph scattering processes, the article unveils microphysical mechanisms contributing to the low κL within KCdAs. Key features include significant anisotropy in Cd atoms, pronounced anharmonicity in K atoms, and relative vibrations in non-equivalent As atomic layers. Cd atoms, situated between As layers, exhibit rattling modes and strong lattice anharmonicity, contributing to the observed low κL. Remarkably flat bands near the valence band maximum translate into high PF, aligning with ultralow κL for exceptional thermoelectric performance. Under optimal temperature and carrier concentration doping, outstanding ZT values are achieved: 4.25 (a(b)-axis, p-type, 3 × 1019 cm−3, 500 K), 0.90 (c-axis, p-type, 5 × 1020 cm−3, 700 K), 1.61 (a(b)-axis, n-type, 2 × 1018 cm−3, 700 K), and 3.06 (c-axis, n-type, 9 × 1017 cm−3, 700 K).
The relation between the structure of the silver network electrodes and the properties of Cu(In,Ga)Se2 (CIGS) solar cells is systemically investigated. The Ag network electrode is deposited onto an Al:ZnO (AZO) thin film, employing a self-forming cracked template. Precise control over the cracked template’s structure is achieved through careful adjustment of temperature and humidity. The Ag network electrodes with different coverage areas and network densities are systemically applied to the CIGS solar cells. It is revealed that predominant fill factor (FF) is influenced by the figure of merit of transparent conducting electrodes, rather than sheet resistance, particularly when the coverage area falls within the range of 1.3–5%. Furthermore, a higher network density corresponds to an enhanced FF when the coverage areas of the Ag networks are similar. When utilizing a thinner AZO film, CIGS solar cells with a surface area of 1.0609 cm2 exhibit a notable performance improvement, with efficiency increasing from 10.48% to 11.63%. This enhancement is primarily attributed to the increase in FF from 45% to 65%. These findings underscore the considerable potential for reducing the thickness of the transparent conductive oxide (TCO) in CIGS modules with implications for practical applications in photovoltaic technology.
The development of cost-effective, highly efficient, and durable electrocatalysts has been a paramount pursuit for advancing the hydrogen evolution reaction (HER). Herein, a simplified synthesis protocol was designed to achieve a self-standing electrode, composed of activated carbon paper embedded with Ru single-atom catalysts and Ru nanoclusters (ACP/RuSAC+C) via acid activation, immersion, and high-temperature pyrolysis. Ab initio molecular dynamics (AIMD) calculations are employed to gain a more profound understanding of the impact of acid activation on carbon paper. Furthermore, the coexistence states of the Ru atoms are confirmed via aberration-corrected scanning transmission electron microscopy (AC-STEM), X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XAS). Experimental measurements and theoretical calculations reveal that introducing a Ru single-atom site adjacent to the Ru nanoclusters induces a synergistic effect, tuning the electronic structure and thereby significantly enhancing their catalytic performance. Notably, the ACP/RuSAC+C exhibits a remarkable turnover frequency (TOF) of 18 s−1 and an exceptional mass activity (MA) of 2.2 A mg−1, surpassing the performance of conventional Pt electrodes. The self-standing electrode, featuring harmoniously coexisting Ru states, stands out as a prospective choice for advancing HER catalysts, enhancing energy efficiency, productivity, and selectivity.
Skin-like electronics research aiming to mimic even surpass human-like specific tactile cognition by operating perception-to-cognition-to-feedback of stimulus to build intelligent cognition systems for certain imperceptible or inappreciable signals was so attractive. Herein, we constructed an all-in-one tri-modal pressure sensing wearable device to address the issue of power supply by integrating multistage microstructured ionic skin (MM i-skin) and thermoelectric self-power staffs, which exhibits high sensitivity simultaneously. The MM i-skin with multi-stage “interlocked” configurations achieved precise recognition of subtle signals, where the sensitivity reached up to 3.95 kPa−1, as well as response time of 46 ms, cyclic stability (over 1500 cycles), a wide detection range of 0–200 kPa. Furthermore, we developed the thermoelectricity nanogenerator, piezoelectricity nanogenerator, and piezocapacitive sensing as an integrated tri-modal pressure sensing, denoted as P-iskin, T-iskin, and C-iskin, respectively. This multifunctional ionic skin enables real-time monitoring of weak body signals, rehab guidance, and robotic motion recognition, demonstrating potential for Internet of things (IoT) applications involving the artificial intelligence-motivated sapiential healthcare Internet (SHI) and widely distributed human-machine interaction (HMI).
The practical application of lithium (Li) metal anodes in high-capacity batteries is impeded by the formation of hazardous Li dendrites. To address this challenge, this research presents a novel methodology that combines laser ablation and heat treatment to precisely induce controlled grain growth within laser-structured grooves on copper (Cu) current collectors. Specifically, this approach enhances the prevalence of Cu (100) facets within the grooves, effectively lowering the overpotential for Li nucleation and promoting preferential Li deposition. Unlike approaches that modify the entire surface of collectors, our work focuses on selectively enhancing lithiophilicity within the grooves to mitigate the formation of Li dendrites and exhibit exceptional performance metrics. The half-cell with these collectors maintains a remarkable Coulombic efficiency of 97.42% over 350 cycles at 1 mA cm−2. The symmetric cell can cycle stably for 1600 h at 0.5 mA cm−2. Furthermore, when integrated with LiFePO4 cathodes, the full-cell configuration demonstrates outstanding capacity retention of 92.39% after 400 cycles at a 1C discharge rate. This study introduces a novel technique for fabricating selective lithiophilic three-dimensional (3D) Cu current collectors, thereby enhancing the performance of Li metal batteries. The insights gained from this approach hold promise for enhancing the performance of all laser-processed 3D Cu current collectors by enabling precise lithiophilic modifications within complex structures.
Zinc metal anodes are gaining popularity in aqueous electrochemical energy storage systems for their high safety, cost-effectiveness, and high capacity. However, the service life of zinc metal anodes is severely constrained by critical challenges, including dendrites, water-induced hydrogen evolution, and passivation. In this study, a protective two-dimensional metal–organic framework interphase is in situ constructed on the zinc anode surface with a novel gel vapor deposition method. The ultrathin interphase layer (∼1 µm) is made of layer-stacking 2D nanosheets with angstrom-level pores of around 2.1 Å, which serves as an ion sieve to reject large solvent–ion pairs while homogenizes the transport of partially desolvated zinc ions, contributing to a uniform and highly reversible zinc deposition. With the shielding of the interphase layer, an ultra-stable zinc plating/stripping is achieved in symmetric cells with cycling over 1000 h at 0.5 mA cm−2 and ∼700 h at 1 mA cm−2, far exceeding that of the bare zinc anodes (250 and 70 h). Furthermore, as a proof-of-concept demonstration, the full cell paired with MnO2 cathode demonstrates improved rate performances and stable cycling (1200 cycles at 1 A g−1). This work provides fresh insights into interphase design to promote the performance of zinc metal anodes.
High-capacity nickel-rich layered oxides are promising cathode materials for high-energy-density lithium batteries. However, the poor structural stability and severe side reactions at the electrode/electrolyte interface result in unsatisfactory cycle performance. Herein, the thin layer of two-dimensional (2D) graphitic carbon-nitride (g-C3N4) is uniformly coated on the LiNi0.8Co0.1Mn0.1O2 (denoted as NCM811@CN) using a facile chemical vaporization-assisted synthesis method. As an ideal protective layer, the g-C3N4 layer effectively avoids direct contact between the NCM811 cathode and the electrolyte, preventing harmful side reactions and inhibiting secondary crystal cracking. Moreover, the unique nanopore structure and abundant nitrogen vacancy edges in g-C3N4 facilitate the adsorption and diffusion of lithium ions, which enhances the lithium deintercalation/intercalation kinetics of the NCM811 cathode. As a result, the NCM811@CN-3wt% cathode exhibits 161.3 mAh g−1 and capacity retention of 84.6% at 0.5 C and 55 °C after 400 cycles and 95.7 mAh g−1 at 10 C, which is greatly superior to the uncoated NCM811 (i.e. 129.3 mAh g−1 and capacity retention of 67.4% at 0.5 C and 55 °C after 220 cycles and 28.8 mAh g−1 at 10 C). The improved cycle performance of the NCM811@CN-3wt% cathode is also applicable to solid–liquid-hybrid cells composed of PVDF:LLZTO electrolyte membranes, which show 163.8 mAh g−1 and the capacity retention of 88.1% at 0.1 C and 30 °C after 200 cycles and 95.3 mAh g−1 at 1 C.
In challenging operational environments, Lithium-ion batteries (LIBs) inevitably experience mechanical stresses, including impacts and extrusion, which can lead to battery damage, failure, and even the occurrence of fire and explosion incidents. Consequently, it is imperative to investigate the safety performance of LIBs under mechanical loads. This study is grounded in a more realistic coupling scenario consisting of electrochemical cycling and low-velocity impact. We systematically and experimentally uncovered the mechanical, electrochemical, and thermal responses, damage behavior, and corresponding mechanisms under various conditions. Our study demonstrates that higher impact energy results in increased structural stiffness, maximum temperature, and maximum voltage drop. Furthermore, heightened impact energy significantly influences the electrical resistance parameters within the internal resistance. We also examined the effects of State of Charge (SOC) and C-rates. The methodology and experimental findings will offer insights for enhancing the safety design, conducting risk assessments, and enabling the cascading utilization of energy storage systems based on LIBs.
As one promising carbon-based material, sp3-hybrid carbon nitride has been predicted with various novel physicochemical properties. However, the synthesis of sp3-hybrid carbon nitride is still limited by the nanaoscale, low crystallinity, complex source, and expensive instruments. Herein, we have presented a facile approach to the sp3-hybrid carbon nitride nano/micro-crystals with microwave-assisted confining growth and liquid exfoliation. Actually, the carbon nitride nano/micro-crystals can spontaneously emerge and grow in the microwave-assisted polymerization of citric acid and urea, and the liquid exfoliation can break the bulk disorder polymer to retrieve the highly crystalline carbon nitride nano/micro-crystals. The obtained carbon nitride nano/micro-crystals present superior blue light absorption strength and surprising photoluminescence quantum yields of 57.96% in ethanol and 18.05% in solid state. The experimental characterizations and density functional theory calculations reveal that the interface-trapped localized exciton may contribute to the excellent intrinsic light emission capability of carbon nitride nano/micro-crystals and the interparticle staggered stacking will prevent the aggregation-caused-quenching partially. Finally, the carbon nitride nano/micro-crystals are demonstrated to be potentially useful as the phosphor medium in light-emitting-diode for interrupting blue light-induced eye damage. This work paves new light on the synthesis strategy of sp3-hybrid carbon nitride materials and thus may push forward the development of multiple carbon nitride research.
Nosocomial infections affect implanted medical devices and greatly challenge their functional outcomes, becoming sometimes life threatening for the patients. Therefore, aggressive antibiotic therapies are administered, which often require the use of last-resort drugs, if the infection is caused by multi-drug-resistant bacteria. Reducing the risk of bacterial contamination of medical devices in the hospitals has thus become an emerging issue. Promising routes to control these infections are based on materials provided with intrinsic bactericidal properties (i.e., chemical action) and on the design of surface coatings able to limit bacteria adhesion and fouling phenomena (i.e., physical action), thus preventing bacterial biofilm formation. Here, we report the development and validation of coatings made of layer-by-layer deposition of electrospun poly(vinylidene fluoride-co-trifluoro ethylene) P(VDF-TrFE) fibers with controlled orientations, which ultimately gave rise to antifouling surfaces. The obtained 10-layer surface morphology with 90° orientation fibers was able to efficiently prevent the adhesion of bacteria, by establishing a superhydrophobic-like behavior compatible with the Cassie-Baxter regimen. Moreover, the results highlighted that surface wettability and bacteria adhesion could be controlled using fibers with diameter comparable to bacteria size (i.e., achievable via electrospinning process), by tuning the intra-fiber spacing, with relevant implications in the future design of biomedical surface coatings.
Finding appropriate photocatalysts for solar-driven water (H2O) splitting to generate hydrogen (H2) fuel is a challenging task, particularly when guided by conventional trial-and-error experimental methods. Here, density functional theory (DFT) is used to explore the MXenes photocatalytic properties, an emerging family of two-dimensional (2D) transition metal carbides and nitrides with chemical formula Mn+1XnTx, known to be semiconductors when having Tx terminations. More than 4,000 MXene structures have been screened, considering different compositional (M, X, Tx, and n) and structural (stacking and termination position) factors, to find suitable MXenes with a bandgap in the visible region and band edges that align with the water-splitting half-reaction potentials. Results from bandgap analysis show how, in general, MXenes with n = 1 and transition metals from group III present the most cases with bandgap and promising sizes, with C-MXenes being superior to N-MXenes. From band alignment calculations of candidate systems with a bandgap larger than 1.23 eV, the minimum required for a water-splitting process, Sc2CT2, Y2CT2 (Tx = Cl, Br, S, and Se) and Y2CI2 are highlighted as adequate photocatalysts.
Sulfide-based inorganic solid electrolytes are promising materials for high-performance safe solid-state batteries. The high ion conductivity, mechanical characteristics, and good processability of sulfide-based inorganic solid electrolytes are desirable properties for realizing high-performance safe solid-state batteries by replacing conventional liquid electrolytes. However, the low chemical and electrochemical stability of sulfide-based inorganic solid electrolytes hinder the commercialization of sulfide-based safe solid-state batteries. Particularly, the instability of sulfide-based inorganic solid electrolytes is intensified in the cathode, comprising various materials. In this study, carbonate-based ionic conductive polymers are introduced to the cathode to protect cathode materials and suppress the reactivity of sulfide electrolytes. Several instruments, including electrochemical spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy, confirm the chemical and electrochemical stability of the polymer electrolytes in contact with sulfide-based inorganic solid electrolytes. Sulfide-based solid-state cells show stable electrochemical performance over 100 cycles when the ionic conductive polymers were applied to the cathode.
The current global warming, coupled with the growing demand for energy in our daily lives, necessitates the development of more efficient and reliable energy storage devices. Lithium batteries (LBs) are at the forefront of emerging power sources addressing these challenges. Recent studies have shown that integrating hexagonal boron nitride (h-BN) nanomaterials into LBs enhances the safety, longevity, and electrochemical performance of all LB components, including electrodes, electrolytes, and separators, thereby suggesting their potential value in advancing eco-friendly energy solutions. This review provides an overview of the most recent applications of h-BN nanomaterials in LBs. It begins with an informative introduction to h-BN nanomaterials and their relevant properties in the context of LB applications. Subsequently, it addresses the challenges posed by h-BN and discusses existing strategies to overcome these limitations, offering valuable insights into the potential of BN nanomaterials. The review then proceeds to outline the functions of h-BN in LB components, emphasizing the molecular-level mechanisms responsible for performance improvements. Finally, the review concludes by presenting the current challenges and prospects of integrating h-BN nanomaterials into battery research.
A commentary on pressure-induced pre-lithiation towards Si anodes in all-solid-state Li-ion batteries (ASSLIBs) using sulfide electrolytes (SEs) is presented. First, feasible pre-lithiation technologies for Si anodes in SE-based ASSLIBs especially the significant pressure-induced pre-lithiation strategies are briefly reviewed. Then, a recent achievement by Meng et al. in this field is elaborated in detail. Finally, the significance of Meng’s work is discussed.
Surface area, pore properties, synergistic behavior, homogenous dispersion, and interactions between carbon matrix and metal-nanostructures are the key factors for achieving the better performance of carbon-metal based (electro)catalysts. However, the traditional hydro- or solvothermal preparation of (electro)catalysts, particularly, bi- or tri-metallic nanostructures anchored graphene (G) or carbon nanotubes (CNTs), often pose to poor metal–support interaction, low synergism, and patchy dispersion. At first, bimetallic flower-like-CuFeS2/NG and cube-like-NiFeS2/NCNTs nanocomposites were prepared by solvothermal method. The resultant bimetallic nanocomposites were employed to derive the 2D-nano-sandwiched Fe2CuNiS4/NGCNTs-SW (electro)catalyst by a very simple and green urea-mediated “mix-heat” method. The desired physicochemical properties of Fe2CuNiS4/NGCNTs-SW such as multiple active sites, strong metal-support interaction, homogenous dispersion and enhanced surface area were confirmed by various microscopic and spectroscopic techniques. To the best of our knowledge, this is the first urea-mediated “mix-heat” method for preparing 2D-nano-sandwiched carbon-metal-based (electro)catalysts. The Fe2CuNiS4/NGCNTs-SW was found to be highly effective for alkaline-mediated oxygen evolution reaction at low onset potential of 284.24 mV, and the stable current density of 10 mA cm−2 in 1.0 M KOH for 10 h. Further, the Fe2CuNiS4/NGCNTs-SW demonstrated excellent catalytic activity in the reduction of 4-nitrophenol with good kapp value of 87.71 × 10−2 s−1 and excellent reusability over five cycles. Overall, the developed urea-mediated “mix-heat” method is highly efficient for the preparation of metal-nanoarchitectures anchored 2D-nano-sandwiched (electro)catalysts with high synergism, uniform dispersion and excellent metal-support interaction.
Rechargeable magnesium metal batteries need an electrolyte that forms a stable and ionically conductive solid electrolyte interphase (SEI) on the anodes. Here, we used molecular dynamic simulation, density functional theory calculation, and X-ray photoelectron spectroscopy analysis to investigate the solvation structures and SEI compositions in electrolytes consisting of dual-salts, magnesium bis(trifluoromethanesulfonyl)imide (MgTFSI2), and MgCl2, with different additives in 1,2-dimethoxyethane (DME) solvent. We found that the formed [Mg3(µ-Cl)4(DME)mTFSI2] (m = 3, 5) inner-shell solvation clusters in MgTFSI2-MgCl2/DME electrolyte could easily decompose and form a MgO- and MgF2-rich SEI. Such electron-rich inorganic species in the SEI, especially MgF2, turned out to be detrimental for Mg plating/stripping. To reduce the MgF2 and MgO contents in SEI, we introduce an electron-deficient tri(2,2,2-trifluoroethyl) borate (TFEB) additive in the electrolyte. Mg//Mg cells using the MgTFSI2-MgCl2/DME-TFEB electrolyte could cycle stably for over 400 h with a small polarization voltage of ∼150 mV. Even with the presence of 800 ppm H2O, the electrolyte with TFEB additive could still preserve its good electrochemical performance. The optimized electrolyte also enabled stable cycling and high-rate capability for Mg//Mo6S8 and Mg//CuS full cells, showing great potential for future applications.
A touch sensor is an essential component in meeting the growing demand for human-machine interfaces. These sensors have been developed in wearable, attachable, and even implantable forms to acquire a wide range of information from humans. To be applied to the human body, sensors are required to be biocompatible and not restrict the natural movement of the body. Ionic materials are a promising candidate for soft touch sensors due to their outstanding properties, which include high stretchability, transparency, ionic conductivity, and biocompatibility. Here, this review discusses the unique features of soft ionic touch point sensors, focusing on the ionic material and its key role in the sensor. The touch sensing mechanisms include piezocapacitive, piezoresistive, surface capacitive, piezoelectric, and triboelectric and triboresistive sensing. This review analyzes the implementation hurdles and future research directions of the soft ionic touch sensors for their transformative potential.
Covalent organic frameworks (COFs) after undergoing the superlithiation process promise high-capacity anodes while suffering from sluggish reaction kinetics and low electrochemical utilization of redox-active sites. Herein, integrating carbon nanotubes (CNTs) with imine-linked covalent organic frameworks (COFs) was rationally executed by in-situ Schiff-base condensation between 1,1′-biphenyl]-3,3′,5,5′-tetracarbaldehyde and 1,4-diaminobenzene in the presence of CNTs to produce core–shell heterostructured composites (CNT@COF). Accordingly, the redox-active shell of COF nanoparticles around one-dimensional conductive CNTs synergistically creates robust three-dimensional hybrid architectures with high specific surface area, thus promoting electron transport and affording abundant active functional groups accessible for electrochemical utilization throughout the whole electrode. Remarkably, upon the full activation with a superlithiation process, the as-fabricated CNT@COF anode achieves a specific capacity of 2324 mAh g−1, which is the highest specific capacity among organic electrode materials reported so far. Meanwhile, the superior rate capability and excellent cycling stability are also obtained. The redox reaction mechanisms for the COF moiety were further revealed by Fourier-transform infrared spectroscopy in conjunction with X-ray photoelectron spectroscopy, involving the reversible redox reactions between lithium ions and C=N groups and gradual electrochemical activation of the unsaturated C=C bonds within COFs.