Ball-Milled Silicon with Amorphous Al₂O₃/C Hybrid Coating Embedded in Graphene/Graphite Nanosheets with a Boosted Lithium Storage Capability

Abstract

Electrochemical active silicon has attracted great attention as anodes for lithium-ion batteries owing to a high theoretical capacity of 4200 mA h g–1. In this work, ball-milled silicon particles with submicron size were strategically modified with a hybrid coating of amorphous alumina and carbon, which simultaneously embedded in a porous framework of in situ exfoliated graphene/graphite nanosheets (GGN). The composite exhibits an enhanced electrochemical performance, including high cycling stability and superior rate capability. An initial discharge capacity of 1294 mA h g–1 and a reversible charge capacity of 1044 mA h g–1 at 0.2 A g–1 can be achieved with a high initial Coulombic efficiency of up to ca. 81%. Additionally, the composite can remain 902 mA h g–1 after 100 discharge/charge cycles, accounting for a high retention of about 86%. This silicon composite is a promising anode material for high performance lithium-ion batteries with a high energy density, and the facile one-pot fabrication route is low cost and scalable, with a great prospect for practical application.