Recycled silicon-based anodes with three-dimensional hierarchical porous carbon framework synthesized by a self-assembly CaCO3 template method for lithium ion battery

Silicon/carbon composite anodes with void space are widely touted as a promising candidate for lithium-ion batteries (LIBs), providing a good volume change tolerance to maintain the integrity of the electrodes. However, the void space is usually created by complicated and environmentally-unfriendly methods with corrosive HF. Herein, a 3D hierarchical porous carbon framework supported silicon-based composite with void space ([email protected]@PC) is synthesized by diluted HCl-assisted etching a self-assembly CaCO3 template method coupled with pyrolysis of citric acid as the carbon source. The [email protected]@PC electrode exhibits reversible capacity retention of 1527 mAhg−1 at 200 mAg−1 after 200 cycles with an initial discharge specific capacity of 3060.6 mAhg−1 and an initial Coulomb efficiency of 74.4%, which is superior to most of that in the reported literatures. This unique structure can not only provide more pathways for lithium ion diffusion and electron transfer but also maintain the integrity of the electrodes. Besides, the effect of lithiation behavior on the solid electrolyte interphase (SEI)-related problems is observed and discussed. This work might provide a facile and green method to synthesize silicon-based anodes with excellent electrochemical performance, and it also can be applied to the design of other materials with porous architecture.