Improved cycling performance of SiOx/MgO/Mg2SiO4/C composite anode materials for lithium-ion battery

Abstract

Silicon suboxide (SiOx) is considered as one of the potential candidates for next-generation lithium-ion battery (LIB) anode materials. However, the application of this material is limited by volume change during the discharging and charging process and its low initial cycle Coulombic efficiency (ICE). Herein, we report a controllable and cost-effective route to synthesize the SiOx/MgO/Mg2SiO4/C (SMC) composite using magesiothermic reaction (MTR), hot-water treatment, and carbonization process. Moreover, the composite exhibits a hierarchical buffer structure composed of microspheres. Because of its special dehydration ability to disrupt the hydrolytic cycle, the introduction of MgO is proved to be beneficial to LIBs’ cycling performance and rate capability. Besides, with the formation of Mg2SiO4, the consumption of SiO2 improves the ICE of the SMC anode to 87.48%. The hierarchical microstructure makes the resultant SMC anode exhibit a stable reversible capacity of 550 mAh g−1, which means a high capacity retention ratio of 78.81% after 200 cycles. Furthermore, the specific capacity of SMC anode keeps around 600 mAh g−1 at the current density of 800 mA g−1, showing superb rate performance. This work provides a novel approach to taking advantage of by-products of MTR and also demonstrates the potential of industrial application of SiOx/C anodes.