High-capacity silicon electrodes obtained from the hydrogen production process by aluminum alloy hydrolysis

Silicon has been considered as one of the most promising anode materials for the next generation of lithium-ion batteries (LIBs) because of its ultrahigh theoretical capacity. However, not only its poor cycle stability and low coulombic efficiency, but also the high-cost, complex preparation methods present significant challenges for its commercialization. Hydrogen, an environmentally friendly and sustainable resource, can be used as fuel or reductant. In this study, we propose an effective strategy for the generation of hydrogen subsequent with the recovery of Si products (R-Si). The addition of Si in the initial Al alloy was demonstrated to be critical for the high-yield production of hydrogen via hydrolysis process. Si product was obtained subsequently by acid washing procedure. When the recovered Si was evaluated as anode material in LIBs, a high initial charge capacity of 3073 mAh/g at a rate of 150 mA/g was obtained. And it also showed excellent initial coulombic efficiency of 86% without any other modification. Furthermore, the R-Si could deliver a reversible capacity of 1735 mAh/g at 1.5 A/g after 100 cycles and have a reversible capacity of 521 mAh/g at 6 A/g. This work will provide referential significance for the research of hydrogen production with Al alloy and facile synthesis of Si anodes.