Composites of Graphene and Encapsulated Silicon for Practically Viable High-Performance Lithium-Ion Batteries

A facile and scalable approach to synthesize silicon composite anode was developed by encapsulating Si particles via in-situ polymerization and carbonization of phloroglucinolformaldehyde gel, followed by incorporation of graphene nanoplatelets. Attributed to the improved structural integrity, a high packing density and an intimate electrical contact consolidated by the conductive networks, the composite anode yielded remarkably enhanced electrochemical performance in terms of charge storage capability, cycling life and coulombic efficiency. A half cell achieved reversible capacities of 1600 mAh g and 1000 mAh g at 0.5 A g and 2.1 A g, respectively, while retaining more than 70% of the initial capacities over 1000 cycles. Complete lithium-ion pouch cells coupling such anode with lithium metal oxide cathode demonstrated superior cycling performance and energy output, representing significant advance in developing Si-based electrode practically applicable to high-performance lithium-ion batteries.