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Metal negative electrodes that alloy with lithium have high theoretical charge storage capacity and are ideal candidates for developing high-energy rechargeable batteries. However, such electrode materials show limited reversibility in Li-ion batteries with standard non-aqueous liquid electrolyte solutions. To circumvent this issue, here we report the use of non-pre-lithiated aluminum-foil-based negative electrodes with engineered microstructures in an all-solid-state Li-ion cell configuration. When a 30-μm-thick Al_94.5In_5.5negative electrode is combined with a Li₆PS₅Cl solid-state electrolyte and a LiNi_0.6Mn_0.2Co_0.2O₂-based positive electrode, lab-scale cells deliver hundreds of stable cycles with practically relevant areal capacities at high current densities (6.5 mA cm⁻²). We also demonstrate that the multiphase Al-In microstructure enables improved rate behavior and enhanced reversibility due to the distributed LiIn network within the aluminum matrix. These results demonstrate the possibility of improved all-solid-state batteries via metallurgical design of negative electrodes while simplifying manufacturing processes.

 

Abstract Nonaqueous sodium-based batteries are ideal candidates for the next generation of electrochemical energy storage devices. However, despite the promising performance at ambient temperature, their low-temperature (e.g., < 0 °C) operation is detrimentally affected by the increase in the electrolyte resistance and solid electrolyte interphase (SEI) instability. Here, to circumvent these issues, we propose specific electrolyte formulations comprising linear and cyclic ether-based solvents and sodium trifluoromethanesulfonate salt that are thermally stable down to −150 °C and enable the formation of a stable SEI at low temperatures. When tested in the Na||Na coin cell configuration, the low-temperature electrolytes enable long-term cycling down to −80 °C. Via ex situ physicochemical (e.g., X-ray photoelectron spectroscopy, cryogenic transmission electron microscopy and atomic force microscopy) electrode measurements and density functional theory calculations, we investigate the mechanisms responsible for efficient low-temperature electrochemical performance. We also report the assembly and testing between −20 °C and −60 °C of full Na||Na 3 V 2 (PO 4 ) 3 coin cells. The cell tested at −40 °C shows an initial discharge capacity of 68 mAh g −1 with a capacity retention of approximately 94% after 100 cycles at 22 mA g −1 . 

Lithium metal and lithium-rich alloys are high-capacity anode materials that could boost the energy content of rechargeable batteries. However, their development has been hindered by rapid capacity decay during cycling, which is driven by the substantial structural, morphological, and volumetric transformations that these materials and their interfaces experience during charge and discharge. During these transformations, the interplay between chemical/structural changes and solid mechanics plays a defining role in determining electrochemical degradation. This Perspective discusses how chemistry and mechanics are interrelated in influencing the reaction mechanisms, stability, and performance of both lithium metal anodes and alloy anodes. Battery systems with liquid electrolytes and solid-state electrolytes are considered because of the distinct effects of chemo-mechanics in each system. Building on this knowledge, we present a discussion of emerging ideas to control and mitigate chemo-mechanical degradation in these materials to enable translation to commercial systems, which could lead to the development of high-energy batteries that are urgently needed to power our increasingly electrified world. 

Operation of lithium‐based batteries at low temperatures (<0 °C) is challenging due to transport limitations as well as sluggish Li⁺kinetics at the electrode interface. The complicated relationships among desolvation, charge transfer, and transport through the solid electrolyte interphase (SEI) at low temperatures are not well understood, hindering electrolyte development. Here, an ether/hydrofluoroether and fluoroethylene carbonate (FEC)‐based ternary solvent electrolyte is developed to improve Li cycling at low temperatures (Coulombic efficiency of 93.3% at ‐40 °C), and the influence of the local solvation structure on interfacial Li⁺kinetics and SEI chemistry is further revealed. The hydrofluoroether cosolvent allows for modulation of the solvation structure, thereby enabling facile Li⁺desolvation while forming an inorganic‐rich SEI, which are both beneficial for lowering Li⁺kinetic barriers at the interface. This cosolvent also increases the oxidative stability of the electrolyte to over 4.0 V versus Li/Li⁺, thereby enabling cycling of NMC‐based full cells at −40 °C. This study advances the understanding of the influence of Li⁺solvation structure, SEI chemistry, and interfacial Li⁺kinetics on Li electrochemistry at low temperatures, providing new design considerations for creating effective low‐temperature electrolyte systems.