Utilizing Room Temperature Liquid Metals for Mechanically Robust Silicon Anodes in Lithium‐Ion Batteries

Silicon has attracted attention as one of the most promising anode materials for future generation energy storage devices, owing to its high theoretical specific capacity. However, its use has been impeded by significant volume expansion during electrochemical lithiation. In this work we utilise liquid galinstan (68.5 % Ga, 21.5 % In and 10 % Sn) to repair the cracking caused by volume expansion in Si thin film and Si composite electrodes. A bridging mechanism is observed, through which the electrical conductivity can be significantly improved. The composite electrode delivers an initial capacity of 2697 mAh g−1 and reaches a coulombic efficiency ∼100 % after 140 cycles. In addition, nanoindentation tests show that a better mechanical behavior is achieved with increased flexibility. We believe that these results may provide a way to prepare mechanically robust high capacity electrodes.