Compared to traditional liquid electrolyte batteries, solid metal batteries offer advantages such as a wide operating temperature range, high energy density, and improved safety, making them a promising energy storage technology. Solid electrolytes, as the core components of solid-state batteries, are key factors in advancing solid-state battery technology. Among various solid electrolytes, Na super ionic conductor (NASICON)-type solid electrolytes exhibit high ionic conductivity (10⁻³ S·cm⁻¹), a wide electrochemical window, and good thermal stability, providing room for the development of high energy-density solid metal batteries. Since the discovery of NASICON-type solid electrolytes in 1976, interest in their use in all-solid-state battery development has grown significantly. In this review, we comprehensively analyze the common features of NASICON lithium-ion conductors and NASICON sodium-ion conductors, review the historical development of NASICON-type solid electrolytes, systematically summarize the transport mechanisms of metal cations in NASICON-type solid electrolytes, discuss the latest strategies for enhancing ionic conductivity, elaborate on the latest methods for improving mechanical stability and interface stability, and point out the requirements of high energy density devices for NASICON-type solid electrolytes as well as three types of in situ characterization techniques for interfaces. Finally, we highlight the challenges and potential solutions for the future development of NASICON-type solid electrolytes and solid-state metal batteries.

Seawater electrolysis is promising for green hydrogen production, while its application is inhibited by sluggish anodic oxygen evolution reaction (OER) and rapid chloride corrosion-induced electrode deactivation. Herein, we report a conductive and ion-selective OER electrocatalyst with a CoFe alloy core and microporous metal-doped carbon shell. Co/Fe-N₄-C active sites in the shell optimize the adsorption strength of intermediates and synergize with the metal core to endow the catalyst with high OER activity and selectivity, while the rich ultra-micropores in the shell demonstrate a significant sieving effect to hinder Cl⁻ transfer, thus protecting the inner Co/Fe-N₄-C active sites and metal core from Cl⁻ corrosion. The catalyst is assembled in an alkaline seawater electrolyzer with an electrode geometric area of 254 cm² and delivers a current density of 3000 A m⁻² at 1.85 V for 330 h. Such catalysts can be synthesized in a large batch (100 g), providing sound opportunities for industrial seawater splitting.

Salination of solutions of salinity gradient releases large-scale clean and renewable energy, which can be directly and efficiently transformed into electrical energy using ion-selective nanofluidic channel membranes. However, conventional ion-selective membranes are typically either cation- or anion-selective. A pH-switchable system capable of dual cation and anion transport along with salt gradient energy harvesting properties has not been demonstrated in ion-selective membranes. Here, we constructed an amphoteric heterolayer metal–organic framework (MOF) membrane with subnanochannels modified with carboxylic and amino functional groups. The amphoteric MOF-composite membrane, AAO/aUiO-66-(COOH)₂/UiO-66-NH₂, exhibits pH-tuneable ion conduction and achieves osmotic energy conversion of 7.4 and 5.7 W/m² in acidic and alkaline conditions, respectively, using a 50-fold salt gradient. For different anions but the same cation diffusion transport, the amphoteric membrane produces an outstanding I⁻/CO₃²⁻ selectivity of ~4160 and an osmotic energy conversion of ~133.5 W/m². The amphoteric membrane concept introduces a new pathway to explore the development of ion transport and separation technologies and their application in osmotic energy-conversion devices and flow batteries.

The practical application of lithium (Li) metal batteries (LMBs) faces challenges due to the irreversible Li deposition/dissolution process, which promotes Li dendrite growth with severe parasitic reactions during cycling. To address these issues, achieving uniform Li-ion flux and improving Li-ion conductivity of the separator are the top priorities. Herein, a separator (PCELS) with enhanced Li-ion conductivity, composed of polymer, ceramic, and electrically conductive carbon, is proposed to facilitate fast Li-ion transport kinetics and increase Li deposition uniformity of the LMBs. The PCELS immobilizes PF₆^– anions with high adsorption energies, leading to a high Li-ion transference number. Simultaneously, the PCELS shows excellent electrolyte wettability on both its sides, promoting rapid ion transport. Moreover, the electrically conductive carbon within the PCELS provides additional electron transport channels, enabling efficient charge transfer and uniform Li-ion flux. With these advantages, the PCELS achieves rapid Li-ion transport kinetics and uniform Li deposition, demonstrating excellent cycling stability over 100 cycles at a high current density of 12.0 mA cm^–2. Furthermore, the PCELS shows stable cycling performances in Li–S cell tests and delivers an excellent capacity retention of 95.45% in the Li|LiFePO₄ full-cell test with a high areal capacity of over 5.5 mAh cm^–2.

Silicon-based anode materials have garnered considerable attention in lithium-ion batteries (LIBs) due to their exceptionally high theoretical capacity and energy density. However, intrinsic challenges, such as significant volumetric expansion and the consequent degradation in cycling stability, severely hinder their practical application. As a result, development of silicon anodes that can effectively mitigate volumetric expansions, enhance cycling durability, and improve rate performance has emerged as a critical research focus. However, due to neglect of “size effects”, the modification strategy of silicon-based electrodes lacks systematic, scientific, and comprehensive guidance. Herein, this review starts from the “size effect” of silicon-based materials, and reveals in depth the different failure mechanisms of nano-silicon (Si NPs) and micro-silicon (μSi). Furthermore, this review provides targeted classification of modification strategies for Si NPs and μSi, and reviews comprehensively, in detail, and in depth the latest research progress on silicon-based materials. In addition, the review also comprehensively summarizes the cutting-edge dynamics of matching silicon-based electrodes with solid electrolytes to construct high-energy LIBs. It is hoped that this review can provide comprehensive and systematic scientific guidance for modification strategies of silicon-based electrodes, which is of great significance for promoting the industrialization process of silicon-based electrodes in high-energy LIBs.

Enhancing the energy density of all-solid-state batteries (ASSBs) with lithium metal anodes is crucial, but lithium dendrite-induced short circuits limit fast-charging capability. This study presents a high-power ASSB employing a novel, robust solid electrolyte (SE) with exceptionally high stability at the lithium metal/SE interface, achieved via site-specific Nb doping in the argyrodite structure. Pentavalent Nb incorporation into Wyckoff 48h sites enhances structural stability, as confirmed by neutron diffraction, X-ray absorption spectroscopy, magic angle spinning nuclear magnetic resonance, and density functional theory calculations. While Nb doping slightly reduces ionic conductivity, it significantly improves interfacial stability, suppressing dendrite formation and enabling a full cell capable of charging in just 6 min (10-C rate, 16 mA cm⁻²). This study highlights, for the first time, that electrochemical stability, rather than ionic conductivity, is key to achieving high-power performance, advancing the commercialization of lithium metal-based ASSBs.

Photoelectrochemistry is a promising method for the direct conversion of sunlight into valuable chemicals by combining the functions of solar panels and electrolyzers in one technology. In most studies, semiconductor/catalyst photoelectrode assemblies are used to achieve reasonable efficiencies. At the same time, unlike in dark electrochemical processes, the role of the catalyst is not straightforward in photoelectrochemistry, where the onset potential of the redox process should be mostly determined by the flatband potential of the semiconductor. In addition, the energy of holes (i.e., the surface potential) is independent of the applied bias; it is defined by the valence band (VB) position. In this study, we compared PdAu, Au, and Ni on Si photoanodes in the photoelectrochemical (PEC) oxidation of glycerol at record high current densities (> 180 mA cm^‒2), coupled to H₂ evolution at the cathode. We successfully decreased the energy requirement (i.e., the cell voltage) of the paired conversion of glycerol and water by 0.7 V by exchanging the widely studied Ni catalyst with PdAu. The catalyst choice also dictates the product distribution, resulting mainly in C3 products on PdAu, glycolate (C2 product) on Au, and formate (C1 product) on Ni, without complete mineralization of glycerol (CO₂ formation) that is difficult to rule out in dark electrochemical processes (as demonstrated by comparative measurements). Finally, we achieved a bias-free (standalone) operation with PdAu/Si and Au/Si photoanodes by combining the PEC oxidation of glycerol with oxygen reduction reaction (ORR).

Organic solar cells (OSCs) have emerged as promising candidates for next-generation photovoltaics, yet traditional bulk heterojunction (BHJ) devices face inherent limitations in morphology control and phase separation. Layer-by-layer (LbL) processing with a p–i–n configuration offers an innovative solution by enabling precise control over donor–acceptor distribution and interfacial characteristics. Here, we systematically investigate nine halogen-functionalized additives across three categories—methyl halides, thiophene halides, and benzene halides—for optimizing LbL device performance. These additives, distinguished by their diverse thermal properties and solid–liquid transformation capabilities below 100°C, are functionalized as both nucleation centers and morphology-modulating plasticizers during thermal treatment. Among them, 2-bromo-5-iodothiophene (BIT) demonstrates superior performance through synergistic effects of its bromine–iodine combination and thiophene core in mediating donor–acceptor interactions. LbL devices processed with BIT achieve exceptional metrics in the PM6/L8-BO system, including a open-circuit voltage of 0.916 V, a short-circuit current density of 27.12 mA cm⁻², and an fill factor of 80.97%, resulting in an impressive power conversion efficiency of 20.12%. This study establishes a molecular design strategy for halogen-functionalized additives that simultaneously optimizes both donor and acceptor layers while maintaining processing simplicity for potential industrial applications.

The design of efficient and cost-effective bifunctional catalysts, which are capable of driving both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), is of paramount importance for advancing overall water splitting. Here, we developed an innovative heterogeneous interface engineering strategy to boost the electrocatalytic performance of overall water splitting. This approach involves the synergistic integration of ultra-fine CoMoP nanocrystals coupled with three-dimensional (3D) porous C₃N₄/N-doped carbon (NC) architectures, constructing a distinctive CoMoP/C₃N₄/NC heterogeneous interface. The CoMoP/C₃N₄/NC exhibits distinguished overall water splitting performance. To drive the overall water splitting current of 10 mA cm⁻², the CoMoP/C₃N₄/NC||CoMoP/C₃N₄/NC electrolysis cell only needs an ultralow cell voltage of 1.496 V. The electronic properties and localized coordination environments characterizations, and density functional theory (DFT) calculations elucidate that the improved catalytic activities of CoMoP/C₃N₄/NC are primarily attributed to the synergistic interfacial coupling between CoMoP/C₃N₄/NC heterogeneous interface. A novel multi-site synergistic catalytic mechanism was revealed by the DFT calculations, in which the optimum H* adsorption site on CoMoP/C₃N₄/NC for HER is on the cobalt atoms in CoMoP with the ultralow Gibbs free energy of hydrogen bonding (ΔG_H*) of 0.018 eV, while for the OER, the optimum intermediates adsorption site of the CoMoP/C₃N₄/NC is on the carbon atoms in C₃N₄/NC. Besides, the intricately engineered 3D hierarchical porous framework of the CoMoP/C₃N₄/NC can facilitate the ion and electron transport and improve mass transfer, which gives rise to enhanced water splitting performance.

Acidic environments enhance CO₂ utilization during CO₂ electrolysis via a buffering effect that converts carbonates formed at the electrode surface back into CO₂. Nevertheless, further investigation into acidic CO₂ electrolysis is required to improve its selectivity towards certain CO₂ reduction reaction (CO₂RR) products, such as multicarbon (C₂₊) species, while enhancing its overall stability. In this study, liquid product recirculation in the catholyte and local OH⁻ accumulation were identified as primary factors contributing to the degradation of gas diffusion electrodes mounted in closed-loop catholyte configurations. We demonstrate that a single-pass catholyte configuration prevents liquid product recirculation and maintains a continuous flow of acidic-pH catholyte throughout the reaction while using the same volume as a closed-loop setup. This approach improves electrode durability and maintains a Faradaic efficiency of 67% for multicarbon products over 4 h of CO₂ electrolysis at −600 mA cm⁻².

Gel polymer electrolytes (GPEs) with high flame-retardant concentration can remarkably reduce the thermal runaway risk of lithium metal batteries (LMBs). However, higher flame-retardant content in GPEs always leads to increased leakage of active component and severe lithium corrosion, which greatly hinders the service life of LMBs. Herein, GPEs with high-loading triphenyl phosphate (TPP) are originally fabricated by coaxial electrospinning and stabilized by dual confinement effects, including chemisorption of polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), and physical encapsulation of polyacrylonitrile (PAN)/PVDF-HFP. These effects arise from the strong polar interactions between the −CF₃ group in PVDF-HFP and P=O group in TPP, as well as the superior anti-swelling property of PAN. To mitigate TPP-induced corrosion during cycling, the optimized Li anode is armored with LiF-rich solid electrolyte interphase (SEI) layer through immersing it in fluoroethylene carbonate-containing electrolyte. As expected, the corresponding Li||Li symmetric cells deliver long-term stable cycling behavior over 2400 h at 0.5 mA cm⁻², and the LiFePO₄||Li batteries hold a high-capacity retention ratio of 81.7% after 6000 cycles at 10 C with excellent flame retardancy. These findings offer new insight into designing the SEI layer for lithium metal in flame-retardant electrolytes, thus promoting the development and application of high-security LMBs.

This study begins by exploring the typical practical applications of phase-change materials (PCMs) in various industries, highlighting their importance in energy storage, temperature regulation, and thermal management. It then emphasizes the necessity of flame-retardant functionalization tailored to the specific application scenarios of PCMs, especially considering their use in safety-critical environments such as electronics, automotive, and construction. The classic characterization methods for assessing the flame-retardant properties of PCM are introduced in detail, including the limiting oxygen index, the vertical burning test, and the cone calorimeter, which are widely recognized standards in material safety testing. Additionally, newly developed methods for evaluating combustion safety are discussed, such as direct combustion tests, candle combustion experiments, and back temperature response, which offer a more comprehensive understanding of the material's fire resistance. Following this, this study provides a thorough summary and categorization of the flame-retardant strategies used in PCMs, divided into four main approaches: (1) incorporation of external flame retardants, (2) use of flame-retardant microcapsules, (3) development of flame-retardant support materials, and (4) creation of intrinsic flame-retardant PCMs. Each strategy is critically analyzed in terms of effectiveness, applicability, and potential challenges. Lastly, the conclusion provides an overview of the current state of flame-retardant PCMs, offering insights into future development directions, including the pursuit of more sustainable and efficient flame-retardant solutions, as well as prospects for their broader adoption in various industries.