Interdigitated Eutectic Alloy Anodes with High-Volumetric Capacity for Lithium-Ion Batteries

Abstract

Interdigitated eutectic alloy (IdEA) foils are highly promising anodes for lithium-ion batteries. The framework appears commercially promising across a variety of metrics; electrode-level volumetric capacity is approximately double that of graphite (798 mA h cm -3 ) , the lithium plating risk is eliminated, formation losses are below < 10%, and coulombic efficiency has reached ~ 99%. Synthesized via severe plastic deformation, a two-phase alloy is converted into a nanostructured foil composed of alloying domains distributed throughout an electrically conductive matrix. The scalable approach uses abundant materials and requires no slurry-coating or drying, potentially eliminating ~ 80% of electrode processing costs. However, the electrochemistry of the system is more complex than would be expected for a simple mixture of the constituent phases. In our Zn-Sn embodiment, long-term degradation was closely correlated with the cycling of a previously unobserved non-equilibrium ternary phase. Given the potential of a nascent system for record volumetric capacity (1,084 mA h cm -3 ) and the broad class of viable IdEA systems, further study is merited, and continued exploration of the IdEA framework may unlock unmatched next-generation anodes. Figure 1