Stable Lithium Metal Anode Enabled by 3D Soft Host

Lithium (Li) metal is among the most promising anode materials for next-generation rechargeable batteries. However, inevitable Li dendrite growth and huge volume expansion severely restrict its practical application. Here, we propose a melamine sponge@silver nanowires (MS@AgNWs) current collector to achieve highly reversible Li storage. By combining the strength advantages of lithophilic nanoseeds, 3D current rectification structure and stress-releasing soft substrate, the MS@AgNWs host can successfully release the compress stress generated during the Li-plating process and hence give rise to uniform Li deposition. In particular, the MS@AgNWs-Li composite anode shows high Coulomb efficiency of 99.1% over 300 cycles and ultralow overpotentials of 10 mV at 1 mA cm-2 and 19 mV at 2 mA h cm-2. Superior long-term cycle stability over 1000 h is attained in symmetric cell under various densities. The assembled full cells with LiFePO4 cathode deliver excellent cycle performance with capacity retention of 138.2 mAh g-1 at 1C after 400 cycles and outstanding rate performance (discharge capacity of 119 mAh g-1 at 10 C). Scalable fabrication of 3D MS@AgNWs flexible host can be easily realized, which is potential for developing practical flexible Li metal based batteries.