Electrochemical performance of SiOC anodes prepared by a different silicone

Abstract SiOC is one of the most promising anodes for lithium‐ion batteries, which shows the good structural stability and high capacity comparing to commercial graphite anode. In this paper, different SiOC anodes (SiOC‐217, SiOC‐H44, and SiOC‐MK) were prepared from polymer precursors with different side groups (phenyl, methyl‐phenyl, methyl) to investigate the effects of free carbon on the electrochemical performance of SiOC anodes. The results of X‐ray photoelectron spectroscopy presented that SiOC was composed by different SiO x C 4− x units and free carbon phase. The initial discharge capacity of SiOC‐217 was 742.67 mA h g −1 . After 100 cycles, the reversible capacity of SiOC‐217 reached 450.65 mA h g −1 at 0.2 C, indicating a capacity retention rate of 60.68%. After cycling at high current densities, SiOC‐217 exhibited a high discharge capacity of 592.88 mA h g −1 at 0.1 C. SiOC‐217 exhibited excellent electrochemical performance due to the high content of free carbon phase. Furthermore, the high contents of SiO 2 C 2 and SiO 3 C units further enhanced the improvement of electrochemical performance.