A self-sacrifice template strategy to fabricate yolk-shell structured silicon@void@carbon composites for high-performance lithium-ion batteries

Due to its high specific capacity, silicon (Si) is considered as the most promising alternative anode material for high energy density lithium-ion batteries, but it suffers from dramatic volume expansion during the charge/discharge process. Fabricating yolk-shell structure is regarded as an essential way to improve the conductivity and cycle stability of Si-based anode. In this work, we proposed a self-sacrifice template strategy by using polyethyleneimine (PEI) to form the void space during carbonation without acid or base etching, which was different from the colloidal templates method. The yolk-shell structured silicon@void@carbon (Si@void@C) composites were synthesized to enhance cycle stability for lithium-ion batteries, which delivered a capacity of 854.1 mAh.g(-1) at the current density of 0.2 A.g(-1) after 200 cycles. Our work is also expected to be extended to the synthesis of other yolk-shell structured composites and the application in energy storage, catalysis, biomedicine and other fields.