A Stretchable Ionic Conductive Elastomer for High‐Areal‐Capacity Lithium‐Metal Batteries

Developing high‐areal‐capacity and dendrite‐free lithium (Li) anodes is of significant importance for the practical applications of the Li‐metal secondary batteries. Herein, an effective strategy to stabilize the high‐areal‐capacity Li electrodeposition by modifying the Li metal with a stretchable ionic conductive elastomer (ICE) is demonstrated. The ICE layer prepared via an instant photocuring process shows a promising Li + ‐ion conductivity at room temperature. When being used in Li‐metal batteries, the thin ICE coating (~0.27 μm) acts as both a stretchable constraint to minimize the Li loss and a protective layer to facilitate the uniform flux of Li ions. With this ICE‐modifying strategy, the reversibility and cyclability of the Li anodes under high‐areal‐capacity condition in carbonate electrolyte are significantly improved, leading to a stable Li stripping/plating for 500 h at an ultrahigh areal capacity of 20 mAh cm −2 in commercial carbonate electrolyte. When coupled with industry‐level thick LiFePO 4 electrodes (20.0 mg cm −2 ), the cells with ICE‐Li anodes show significantly enhanced rate and cycling capability.