Graphene bubble film encapsulated Si@C hollow spheres as a durable anode material for lithium storage

Silicon-based composites have been proposed as the promising anode materials for Li-ion batteries. In order to avoid the operational problems of silicon-based anodes such as the low electric conductivity and huge volume expansion, we succeed in encapsulating Si@C hollow spheres into flexible graphene bubble film as a durable anode with enhanced lithium storage properties. In this design, sub -micrometer-sized Si hollow spheres are wrapped into accessible mesoporous carbon shells. Then, the Si@C hollow spheres are tightly wrapped with amino-functionalized graphene oxide nanosheets and followed by chemical reduction to form a bubble film composite structure. Such closely packed graphene bubble films encapsulating hollow Si@C macrostructure ensures uniform and aggregation-free distribution of silicon spheres in the dual conductive carbon network. This kind of graceful composite structure can not only suppress volume expansion and improve structural stability of the electrode material, but also facilitate the electron transfer and lithium ion migration by shortening the transportation channels. The as-prepared composite exhibits impressive Li storage performance with a high reversible capacity of 813.2 mAh g(-1) after 100 cycles at 0.1C. This work offers an appealing strategy for high-performance Si-based anode materials in practical application. (C) 2020 Elsevier Ltd. All rights reserved.