Li-rich Mn-based cathode materials (LRM) have received great attention owing to their high capacity and low cost. However, the mismatch between the widely used carbonate electrolyte and the LRM cathode and lithium metal anode causes a series of problems, such as electrolyte continuous oxidation, cathode structure degradation, and Li dendritic growth. Herein, inorganic oxide B2O3 is introduced as a dual-functional high-voltage electrolyte additive to construct stable cathode electrolyte interphase and solid electrolyte interphase for Li||LRM batteries. The modified interface derived from the additive can induce dendrite-free Li deposition, stabilize cathode structure, and inhibit transition metal dissolution. Moreover, the adverse side reactions are mitigated, thus enhancing Li+ transport rate and reducing interface impedance. With the addition of B2O3 into the carbonate electrolyte, the Li||LRM battery exhibits an enhanced discharge capacity of 221 mAh g-1 after 200 cycles, equaling a capacity retention of 92.1%. When the upper cut-off voltage is increased to 5 V, a superior capacity retention of > 85% can still be achieved after 150 cycles at 1 C. In addition, the low cost of B2O3 benefits for commercial application. This work offers new guidance for the research of low-cost, high-voltage dual-functional additives for advanced lithium metal batteries.
Compaction pressure directly determines the compactness of solid-state electrolytes (SSEs), which is crucial to affect the electrochemical performance of solid-state lithium batteries (SLBs). Herein, Li6.5La3Zr1.5Ta0.5O12 (LLZTO) pellets are compacted under various pressures before sintering to study the impact of compaction pressure on the overall properties of LLZTO SSEs and their SLBs. Notably, the sample pressed at 600 MPa (LLZTO-600) exhibits the highest compactness and the highest ionic conductivity due to improved particle contact and suppressed lithium loss. Consequently, the Li|LLZTO-600|Li symmetric cell exhibits the best performance among the samples, which can stably cycle for 1,500 h without short circuits. Meanwhile, the LiFePO4|LLZTO-600|Li full cell can retain 94.8% of its initial capacity after 150 cycles with the lowest overpotential among the SSEs. This work highlights the importance of tuning compaction pressure in developing high-performance SSEs and related SLBs.
Aqueous zinc-sulfur batteries (AZSBs) have emerged as promising candidates for high-energy density, cost-effective, and environmentally sustainable energy storage systems. Despite their potential, several challenges hinder the realization of high-performance AZSBs, including sluggish reaction kinetics, disproportionation reactions of ZnS in water, low conductivity and volume expansion of the sulfur cathode, poor wetting properties, and dendrite growth issues of the zinc anode. This review comprehensively summarizes optimization strategies for overcoming these challenges. We discuss cathode modification approaches, such as sulfur/carbon composites, sulfide composites, and catalytic sulfur matrices, which address low conductivity and volume expansion while enhancing sulfur conversion reaction kinetics. Additionally, electrolyte engineering strategies, including the use of iodide-based additives and co-solvent modifications, are examined for their effectiveness in improving reaction kinetics and wetting properties. Despite these advancements, AZSBs still face issues with long-cycle stability. Therefore, this review proposes future perspectives for the development of AZSBs. We aim to provide valuable insights into sulfur-based cathode materials and advance the achievement of high-performance AZSBs.
Covalent organic frameworks (COFs) have great potential as electrodes for aqueous hybrid supercapacitors (AHCs) owing to their designable structure and resourceful advantages. However, their low capacities and high structure instability in aqueous electrolytes limit the onward practical applications. Here, we have synthesized robust hexaazatrinaphthylene-based COF (HATN-COF) by a simple condensation between cyclohexanehexone and 2,3,6,7,10,11-hexaiminotriphenylene. The π-conjugation skeleton, porous structure, and high-proportioned imine bonds give HATN-COF sufficient electron and ion diffusion pathways for rapid reaction kinetics together with abundant exposed active sites for large capacity. Meanwhile, the formed hydrogen bond networks by ethanol molecules in frameworks improve the acid-base tolerance. As a consequence, HATN-COF delivers an exceptional specific capacity of 367 mAhg-1 at 1 A g-1 (maximum value among reported COF-related electrodes in AHCs), high rate capability with 259.7 mAhg-1 at 20 A g-1, and superior cycle durability with retaining 97.8% of its capacity even after 20,000 cycles. Moreover, the AHC, constructed by HATN-COF as the positive electrode and activated carbon as the negative electrode, exhibits a large energy density of 67 Wh kg-1 at a power density of 375 W kg-1, accompanied by outstanding cycling stability. The research presents a promising approach for designing
This review paper examines the innovative use of liquid crystals (LCs) as phase change materials in thermal energy storage systems. With the rising demand for efficient energy storage, LCs offer unique opportunities owing to their tunable phase transitions, high latent heat, and favorable thermal conductivity. This paper covers various types of LCs, such as nematic, smectic, and cholesteric phases, and their roles in enhancing thermal energy storage. It discusses the mechanisms of LC phase transitions and their impact on energy storage efficiency. Strategies to improve the thermal conductivities of LCs and LC polymers have also been explored. One method involves embedding LC units within the molecular structure to promote orderly arrangement, facilitate heat flow, and reduce phonon scattering. Aligning polymer chains through external fields or mechanical processes significantly improves intrinsic thermal conductivity. The inclusion of thermally conductive fillers and optimization of filler-matrix interactions further boost thermal performance. Challenges related to the scalability, cost-effectiveness, and long-term stability of LC-based phase change materials are addressed, along with future research directions. This review synthesizes the current knowledge and identifies gaps in the literature, providing a valuable resource for researchers and engineers to develop advanced thermal energy storage technologies, contributing to sustainable energy solutions.
The rational design of Pd-based catalysts to enhance their applications in ethanol oxidation reaction (EOR) presents both exciting opportunities and significant challenges. Herein, a series of carbon-supported PdSn nanoparticle catalysts (PdSn/C-X, X = 0.1, 0.5, 1, 2) with tunable lattice strains were synthesized using a facile method at room temperature and applied to the EOR. Our findings demonstrate that the activity and stability of EOR can be modulated by manipulating the lattice strain in Pd-based catalysts. Remarkably, PdSn/C-1 exhibits an excellent mass current density of 8,452.3 mA/mgPd, which is higher than that of most Pd-based catalysts, along with great stability, maintaining a mass activity of 573.9 mA/mgPd after 5,000 s. By combining structural analysis, in situ spectral characterization, and theoretical calculation, we elucidate that the optimal tensile strain adjusted by Sn composition in PdSn/C optimizes the free energy of the key intermediate (*CH2CO) during EOR, thereby favoring the C1 pathway and enhancing catalytic activity. This study demonstrates that by controlling the composition, the lattice strain can be altered to improve catalytic performance of Pd-based catalysts in EOR.
Increasing atmospheric CO2 levels and global carbon neutrality goals have driven interest in technologies that both mitigate CO2 emissions and provide sustainable energy storage solutions. Metal-carbon dioxide (M-CO2) batteries offer significant promise due to their high energy density and potential to utilize atmospheric CO2. A key challenge in advancing M-CO2 batteries lies in optimizing CO2-breathing cathodes, which are essential for CO2 adsorption, diffusion, and conversion. Carbon-based cathodes play a critical role in facilitating CO2 redox for M-CO2 batteries, owing to their cost-effectiveness, high conductivity, tunable microstructure, and porosity. However, there is a lack of current systematic understanding of the relationship between the structure, composition, and catalytic properties of carbon-based cathodes, as well as their impact on the overall efficiency, stability, and durability of
Quasi-solid polymer electrolytes (QSPEs) are considered a promising alternative to liquid electrolytes for high-voltage lithium metal batteries. Herein, we present their properties and performance supported on polyolefin microporous separators. These QSPEs consist of a poly(vinylidene-fluoride-co-hexafluoropropylene) polymer matrix, ethylene carbonate as a plasticizer, and various lithium salt mixtures, including lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(oxalate)borate (LiBOB), and LiNO3 as a solid electrolyte interface-forming additive. They exhibit an ionic conductivity of ca. 1 mS cm-1 at room temperature and excellent resistance against lithium dendrites, attributed to the presence of the tough polyolefin separator. The effect of the lithium salt mixture composition on lithium plating/stripping performance and electrooxidation stability was studied in detail, showing that LiNO3, while having a clear positive effect on the plating/stripping performance, may also adversely affect the oxidative stability of the electrolyte, accelerating the degradation of the cathode/electrolyte interface. QSPEs with binary LiFSI/LiBOB salt mixtures were tested at room temperature in a LiNi0.8Mn0.1Co0.1O2||Li monolayer pouch cell with a cathode area capacity of ca. 2.5 mAh cm-2. This cell delivered an initial capacity close to
The interest in lithium solid-state batteries (LSSBs) is rapidly escalating, driven by their impressive energy density and safety features. However, they face crucial challenges, including limited ionic conductivity, high interfacial resistance, and unwanted side reactions. Intensive research has been conducted on polymer solid-state electrolytes positioned between the anode and cathode, aiming to replace traditional liquid electrolytes. To alleviate interfacial resistance and mitigate adverse reactions between electrodes and polymer electrolytes, the interfacial modification strategy has been proven to enhance the energy density of LSSBs. This design process is grounded in precise and elaborate theories, with in-situ/operando techniques and simulation methods facilitating the interpretation and validation of structure-property relationships by simplifying them. This review first outlines the recent advancements in surface modification strategies specifically tailored for solid polymer electrolytes. Furthermore, it also provides an overview of innovative in-situ/operando characterizations and simulation methods featured in recent publications, which can gain a more accurate understanding of processes that occur within materials, devices, or chemical reactions as they are happening. Lastly, the review discusses the existing challenges and presents a forward-looking perspective on the future of the next-generation LSSBs.
Phase change materials (PCMs) represent an innovative solution to passively manage device temperature or store heat, taking advantage of the material phase transitions. In this work, the attitude of high density polyethylene (HDPE) for the shape stabilization of three selected organic PCMs with a melting temperature close to 55 °C was investigated. Composites with PCM content in the range of 50-61 wt.% were produced by melt compounding, and lab-scale panels were produced by compression molding. The ability of the supporting olefinic matrix to stabilize the PCM and contain leakage was verified and compared through thermo-mechanical characterization. Moreover, expanded graphite was introduced according to a novel vacuum impregnation process in order to provide an extra stabilizing contribution, resulting in an outstanding thermal conductivity increase of up to 1.6 W/m·K, and a maximized enthalpy of 112 J/g. Besides the shape stability, HDPE also improves the mechanical properties of PCM-based composites, as documented by detailed and extended characterization through cold and hot compression tests, flexural tests, Vicat and shore A tests. The thermal management effect of the materials is quantified through infrared thermography, by proportionally relating the temperature lags to the high melting/crystallization enthalpy of the investigated products. In view of thermal management applications in the range of 30-60 °C, the main properties of selected HDPE panels with different PCMs are summarized and compared.