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Garnet‐based solid electrolytes (SEs), which have both high ionic conductivity and great stability with Li metal anodes, are at the center of an ever‐increasing research effort in all‐solid‐state lithium metal batteries (ASSLMBs) toward high safety and high energy density. However, the performance of garnet‐based ASSLMBs is limited by the poor ionic conduction on the cathode side, mainly attributed to the inherent rigidity of oxide ceramic nature. Here, a sintering‐free strategy to boost the ionic conduction of the composite cathode via the use of a soft halide SE is presented. The inclusion of the cathode‐compatible halide SE facilitates efficient and stable Li+ conduction within the composite cathode and at the cathode/garnet pellet interface. Compared to the conventional co‐sintered method, the issues associated with element diffusion between solid particles during high‐temperature processes are circumvented, a factor responsible for the degradation and irreversible capacity reduction of the cathode active material. When combined with a lithium metal anode, the new cathode configuration exhibits decent discharge capacity, superior Coulombic efficiency, and enhanced cycle stability. The findings demonstrate the promise of this composite cathode design as a viable pathway for achieving high‐performance garnet‐based ASSLMBs. [ABSTRACT FROM AUTHOR]

Taken the unlimited Na reservoir worldwide, battery technology based on Na-ion chemistry poses as an ideal candidate for large-scale energy storage systems. Especially, with metallic Na replacing traditional carbon anodes, it's able to maximize the energy density inexpensively. Nevertheless, sodium metal batteries (SMBs) face intrinsically poor stability due to their highly-reactive nature, where low Coulombic efficiency and short lifetime are often witnessed. The situation can be further aggravated at low temperatures due to insurmountable kinetic barriers. Herein, a 1,3-dioxolane-based quasi-solid-state electrolyte (PDGE) is proposed with a high ionic conductivity of3.68 mS cm-1 even at -20 °C for SMBs. Moreover, a weak solvation environment is tailored by PDGE, which possesses a high Na+ transference number of 0.7. Concurrently, the solid electrolyte interphase induced from PDGE presents inorganic Na2O, NaF as the major components, which offers accelerated Na+ diffusion and superior stability upon long-term cycling. With such a quasi-solid-state electrolyte, the Na/Na3V2(PO4)3 full cell exhibits great stability over 1000 cycles at -20 °C. This study has significant implications to the development for SMBs under low-temperature conditions. [ABSTRACT FROM AUTHOR]

Lithium metal anodes may allow the energy density limit of rechargeable lithium batteries to be pushed higher. However, simple and efficient processing technologies for thin Li metal are lacking, which has significantly limited its applications. Herein, the feasibility of engineering Li metal by compositing it with ferromagnetic particles (termed magnetic Li, abbr. M‐Li) is reported. Due to its magnetic response, straightforward processing of M‐Li on diverse substrates with customized patterns and desired thickness is realized. Moreover, when a garnet‐type solid‐state electrolyte Li6.5La3Zr1.5Ta0.5O12 (LLZTO) is the substrate, intimate contact between M‐Li and LLZTO is obtained, with a low interfacial resistance of ≈11 Ω cm2. In addition to facilitating movement and wetting on various substrates, magnetic transfer of M‐Li sheets to designated locations is also enabled. The intriguing and brand‐new method for Li metal engineering via magnetic actuation may be adopted by the industrial system for the fabrication of Li metal batteries, extended to other alkali metals and promises further progress. [ABSTRACT FROM AUTHOR]

[Display omitted] • A mild electrochemical etching method is demonstrated for preparing porous Al foil. • Enlarged surface roughness ensures optimized surface free energy and improved wettability. • Finite element analysis indicates boosted charge transfer involving porous Al foil. • Stronger interface adhesion and regulated current density distribution is achieved. • This strategy can be extended for surface modification of other Al-based alloys. Desirable electron transfer via current collectors between as-supported active materials and external circuit is imperative to realize targeted electrochemistry. Enabling surface-mediated pathway of charge carriers in a controllable and efficient manner needs to be carefully addressed but remains a great challenge. Here, we present a cost-efficient strategy for surface modification on Al foils by employing mild electrochemical etching. Well-defined porous nanostructure can be established on commercial Al foils towards promoted surface free energy, which can be also applied on bulk Al-based alloys. Owing to the tailored porosity and increased roughness, desired wetting properties and more importantly, regulated distribution of current density have been realised, according to both experimental observations and simulation results. As expected, LiFePO 4 cathodes loaded on porous Al foils demonstrate improved energy density and cycling stability for lithium-ion batteries (LIBs). [ABSTRACT FROM AUTHOR]