Solid-state batteries (SSBs) are promising for safer energy storage, but their active loading and energy density have been limited by large interfacial impedance caused by the poor Li transport kinetics between the solid-state electrolyte and the electrode materials. To address the interfacial issue and achieve higher energy density, herein, a novel solid-like electrolyte (SLE) based on ionic-liquid-impregnated metal-organic framework nanocrystals (Li-IL@MOF) is reported, which demonstrates excellent electrochemical properties, including a high room-temperature ionic conductivity of 3.0 × 10 S cm , an improved Li transference number of 0.36, and good compatibilities against both Li metal and active electrodes with low interfacial resistances. The Li-IL@MOF SLE is further integrated into a rechargeable Li|LiFePO SSB with an unprecedented active loading of 25 mg cm , and the battery exhibits remarkable performance over a wide temperature range from -20 up to 150 °C. Besides the intrinsically high ionic conductivity of Li-IL@MOF, the unique interfacial contact between the SLE and the active electrodes owing to an interfacial wettability effect of the nanoconfined Li-IL guests, which creates an effective 3D Li conductive network throughout the whole battery, is considered to be the key factor for the excellent performance of the SSB.

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Aqueous electrolytes come with an intrinsic narrow electrochemical stability window (1.23 V). Expanding this window represents significant benefits in both fundamental science and practical battery applications. Recent breakthroughs made via super-concentration have resulted in >3.0 V windows, but fundamental understanding of the related mechanism is still absent. In the present work, we examined the widened window (2.55 V) of a super-concentrated (unsaturated) aqueous solution of LiNO 3 through both theoretical and spectral analyses and discovered that a local structure of intimate Li + -water interaction arises at super-concentration, generating (Li + (H 2 O) 2 ) n polymer-like chains to replace the ubiquitous hydrogen bonding between water molecules. Such structure is mainly responsible for the expanded electrochemical stability window. Further theoretical and experimental analyses quantitatively differentiate the contributions to this window, identifying the kinetic factor (desolvation) as the main contributor. Such molecular-level and quantitative understanding will further assist in tailor designing more effective approaches to stabilizing water electrochemically.

Aqueous zinc (Zn) batteries (AZBs) are widely considered as a promising candidate for next‐generation energy storage owing to their excellent safety features. However, the application of a Zn anode is hindered by severe dendrite formation and side reactions. Herein, an interfacial bridged organic–inorganic hybrid protection layer (Nafion‐Zn‐X) is developed by complexing inorganic Zn‐X zeolite nanoparticles with Nafion, which shifts ion transport from channel transport in Nafion to a hopping mechanism in the organic–inorganic interface. This unique organic–inorganic structure is found to effectively suppress dendrite growth and side reactions of the Zn anode. Consequently, the Zn@Nafion‐Zn‐X composite anode delivers high coulombic efficiency (ca. 97 %), deep Zn plating/stripping (10 mAh cm−2), and long cycle life (over 10 000 cycles). By tackling the intrinsic chemical/electrochemical issues, the proposed strategy provides a versatile remedy for the limited cycle life of the Zn anode.

The formation of dendrites on a zinc (Zn) metal anode has limited its practical applications on aqueous batteries. Herein, an artificial composite protective layer consisting of nanosized metal–organic frameworks (MOFs) to improve the poor wetting effect of aqueous electrolytes on the Zn anode is proposed to reconstruct the Zn/electrolyte interface. In this layer, hydrophilic MOF nanoparticles serve as interconnecting electrolyte reservoirs enabling nanolevel wetting effect as well as regulating an electrolyte flux on Zn anode. This zincophilic interface exhibits significantly reduced charge-transfer resistance. As a result, stable and dendrite-free Zn plating/stripping cycling performance is achieved for over 500 cycles. In addition, especially at higher C-rates, the coating layer significantly reduces the overpotentials in a Zn/MnO2 aqueous battery during cycling. The proposed principle and method in this work demonstrate an effective way to reconstruct a stable interface on metal anodes (e.g., Zn) where a conventional solid-electrolyte interface (SEI) cannot be formed.

Alkali-metal batteries (AMBs) are one of the most promising candidates for next-generation high-energy battery systems. However, dendrite growth and serious safety implications limit the commercialization of AMBs. After years of development, the process of bringing alkali-metal anodes from lab to market is still full of tremendous challenges in terms of safety and cycle life. In this review, we divide the commercialization process of alkali-metal anodes into three stages: the first stage is fundamental researches on alkali-metal anodes, the second stage is the application of alkali-metal anodes in high-energy-density battery systems, and the third stage is satisfying the needs of industrialization. We mainly focus on the second and third stages and attempt to establish a relationship between academia and industry in this field. Finally, we give several perspectives on opportunities and challenges in the future development of AMBs for practical applications.

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Garnet‐type solid‐state electrolytes (SSEs) have been widely studied as a promising candidate for Li metal batteries. Despite the common belief that inorganic SSEs can prevent dendrite propagation, garnet SSEs suffer from relatively low critical current density (CCD) at which the SSEs are abruptly short‐circuited by Li dendrites. In this study, the short‐circuiting mechanism of garnet Li7La2.75Ca0.25Zr1.75Nb0.25O12 (LLCZN) is investigated. It is found that instead of propagating uniaxially from one electrode to other in a dendritic form, metallic lithium is formed within the SSE. This can be attributed to the fact that electrons combine with Li ions at the grain boundary, which exhibits relatively high electronic conductivity, and then reduce Li+ to Li0 to cause short circuits. In order to reduce the electronic conductivity at the grain boundary, a thin layer of LiAlO2 is coated on the grain surface of LLCZN, which results in an improved CCD value. It is also found that under higher external voltages, the electronic conductivity of SSE becomes more significant, which is believed to be the origin of CCD. These findings not only shed light on the short‐circuiting mechanism of garnet‐type SSEs but also offer a novel perspective and useful guidance on their designs and modifications.