Low-temperature fabrication of porous SiO with carbon shell for high-stability lithium ion battery

Porous silicon monoxide (p-SiO) is one of the most promising anode materials for lithium-ion batteries because it possesses high theoretical capacity and small volume expansion. Traditionally, SiO is prepared at 1200 degrees C, which restrains the application of SiO materials due to its high consumption of energy. Herein, a low-temperature synthesis process of p-SiO at 650 degrees C is developed from a controllable magnesiothermic reduction of porous silica. Compared with normally reduced solid silica (SiO2@SiO), p-SiO is fabricated more easily from porous SiO2 due to the improved contact between SiO2 and Mg atom. Moreover, high porosity of p-SiO facilitates the growth of carbon shell, making p-SiO@C with remarkable electrochemical properties. The reversible capacity for p-SiO@C (839.6 mA h g(-1), at 500 mA g(-1)) is about two times that for SiO2 @SiO@C (426.4 mA h g(-1), at 500 mA g(-1) ) after 110 cycles, and the synergetic properties of p-SiO@C further presents good cycling stability (777.1 mA h g(-1), at 500 mA g(-1) after 300 cycles) and excellent rate capability (977 mA h g(-1), at 1000 mA g(-1)). The low-temperature fabrication of p-SiO followed by carbonization is promoting for practical application in high-performance Si-based lithium-ion battery.