SiO anode with long-term cycling ability enhanced by a SiC transition layer based on polymethysilane in LIBs

Poor intrinsic conductivity and significant volume expansion inhibit the application of SiO which shows high specific capacity in LIBs. In this study, we successfully prepared a SiC transition layer in the middle of SiO@C anode material to reduce its volume swelling by the direct infiltration and pyrolysis of polymethysilane. The results demonstrated that the introduction of the SiC transition layer effectively improved the electrochemical behavior of the SiO anode. The SiO@SiC@C composite showed a high initial coulombic efficiency of 78.99% and a reversible capacity of 1148.7 mAh g−1 after 200 cycles at 0.5 A g−1, which displayed an extreme capacity retention of 91% compared to second discharge capacity (1263.5 mAh g−1). Moreover, the SiO@SiC@C exhibited superior rate capability of an average capacity recovery rate of 97% when the rate cycle recovered from 3 A g−1 to 0.1 A g−1. It also displayed outstanding long-term cycling stability, retaining 78% of its discharge capacity of 483.3 mAh g−1 after 1000 cycles compared to the 7th cycle even at 3 A g−1. In conclusion, the incorporation of the SiC transition layer for SiO electrodes exhibited considerable potential for developing high-performance anodes.