Amphiphilic-triblock-copolymer-derived protective layer for stable-cycling lithium metal anodes

Lithium metal batteries have shown great potential for the development of efficient energy storage devices. However, the uncontrollable growth of lithium metal dendrites results in poor cycling efficiency and severe safety concerns. In this study, amphiphilic triblock copolymers (P123) were used for the direct polymerization of silica precursors, resulting in a well-ordered mesoporous silica structure SBA-15 with a large surface area and excellent absorbent properties for the protective layer. The protective layer consisting of SBA-15 stores Li ions in a large number of pores as an electrolyte reservoir, which exhibits sufficient ionic conductivity. Furthermore, it ensures a spatially uniform Li-ion flux on the anode surface and plays an important role in the physical blocking of dendrite growth. As proof of concept, the SAB-15 protective layer anode demonstrates a high average Coulomb efficiency, rate capability, and cycle stability at 1 mA h cm−2 over 1200 cycles. Moreover, SAB-15 can be cycled stably for more than 750 cycles in symmetric cells. The results provide insights for implementing stable lithium metal anodes in next-generation batteries.