Porous Metals from Chemical Dealloying for Solid-State Battery Anodes

Alloy anodes for lithium-ion batteries feature greater specific capacity than conventional graphite electrodes and could enable batteries with higher energy density. However, large volumetric and structural changes during cycling limit performance. Such transformations are expected to be particularly problematic in solid-state batteries, where volume changes can exacerbate chemomechanical degradation of the all-solid structure. Here, we synthesize porous metal foils with bicontinuous porosity by chemical dealloying of Li–In and Li–Sn alloys in dry methanol. Porous indium foils are directly used as the anode in both solid-state and liquid-electrolyte cells, and they exhibit improved capacity and cycle life in solid-state batteries compared to dense indium foil with similar mass loading. Furthermore, capacity retention with cycling of the porous electrodes is much better in solid-state cells than in liquid cells. This performance enhancement is due to improved accommodation of volume changes while minimizing surface side reactions throughout the porous electrode. These results highlight the promise of porous metals for solid-state batteries.