Green and facile fabrication of nanoporous silicon@carbon from commercial alloy with high graphitization degree for high-energy lithium-ion batteries

Silicon (Si) is considered as one of the most promising anodes for lithium-ion batteries (LIBs). However, rapid capacity decay caused by huge volume change and low electrical conductivity limit its further development. Herein, uniform porous Si@C (pSi@C) from commercial Mg2Si alloy and pitch is synthesized by green vacuum distillation method. During this process, the low boiling-point Mg is evaporated and cycled to form porous Si. Besides, the high-graphitization C layer is obtained because the metallic Mg favors the graphitization degree of C. Asa result, the carbon coating layer and unique porous structure can improve electrical conductivity and accommodate volume change of Si anode without destroying solid electrolyte interface. The optimal pSi@C shows improved lithium storage with stable cyclability and superior rate capability. (C) 2020 Elsevier B.V. All rights reserved.