An Investigation of Synthesis, Electrochemistry and Thermal Stability of Ball-milled Si-based Alloy Anodes in Lithium-ion Batteries

The huge volume change of Si anode with fast capacity degradation limits its commercialization in LIBs. The co-introduction of metal and O elements into the Si bulk fabricating Si-metal silicide-Si oxides composites has been proven an effective way to overcome this issue. Among them, Si-CuO composites, due to financial feasibility and environmentally compatibility, have attracted much attention recent years but still with the unsatisfactory cycle performance. In order to optimize the cycle stability of Si-CuO composites, NiO is firstly introduced into the Si-CuO system with different proportion from 10 % to 20 % by a facile and low-cost HEBM method. The study reveals that Si72CuO8NiO20, with the least volume change percentage of ~ 133 %, has a highest capacity retention of ~ 86. 9% after 100 cycles at 0.2 C and average coulombic efficiency of ~ 99.4 % as well as a competitive volumetric capacity of ~ 1700 Ah·L-1 based on the 2nd lithiation. These results confirm the effectiveness of the NiO introduction to improve the cycle performance of the Si-CuO composites. Moreover, in order to make sure the ball-milled Si-CuO-NiO precursors can be well compatible with the high-temperature post-treatment of coating a carbon layer, the thermal stability of Si72CuO8NiO20 is also conducted with the best cycle stability at 600 °C.