Hierarchically porous SiOx/C and carbon materials from one biomass waste precursor toward high-performance lithium/sodium storage

Silicon (Si)-based materials have emerged as promising anode materials owing to the theoretical capacity as high as 4200 mAh g−1 and satisfying working potential for lithium insertion. However, silicon-based anode materials inevitably face the dilemmas of huge volume variation and poor electric conductivity. In this study, three-dimensional (3D) hierarchically porous SiOx/C and carbon materials have been designed and fabricated from one renewable biomass precursor (i.e., bamboo shoot hulls) through low-temperature activated treatment and mildly aluminothermic reduction. The SiOx/C anode after pre-lithiation treatment achieves an initial discharge capacity of 1332 mAh g−1 and a high capacity of 1289 mAh g−1 after 400 cycles at 200 mA g−1 as anode electrode for half lithium-ion batteries (LIBs). When employed for full LIBs, the SiOx/C exhibits a specific capacity of 142 mAh g−1 at 0.1 C with prominent cyclic stability and exceptionally low volume expansion. Moreover, hierarchically porous carbons are also prepared from the same precursor through activation of CuCl2 and further removal of SiO2, exhibiting excellent electrochemical performances for lithium/sodium ion batteries.