Si Nanoparticles Intercalated into Interlayers of Slightly Exfoliated Graphite filled by Carbon as Anode with High Volumetric Capacity for Lithium-ion Battery

Abstract

To boost the commercialization of high energy density lithium ion batteries (LIBs) used for electric vehicles, the development of electrode materials with high volumetric capacity is of great significance. In this work, a novel Si/slightly exfoliated graphite (SEG)/carbon composite used as anode for LIBs with high volumetric capacity is fabricated. The Si nanoparticles are uniformly intercalated in the squashed interlayers of SEG which are then further filled by amorphous carbon. The SEG acts as a conductivity skeleton, while the spaces between squashed interlayers(folds) in SEG function as buffer spaces for the expansion of Si nanoparticles during lithiation reactions. The amorphous carbon connects the Si nanoparticles with SEG to form a 3D conductive network. Owing to the high packing density (0.7gcm−3) and unique structure, this material possesses a high volumetric capacity of 1050mAhcm−3. Meanwhile, the Si/SEG/C composite also exhibits excellent rate and cyclic performance, presenting a reversible capacities of 1456 and 1056mAhg−1 at 100 and 500mAg−1 with capacity retention of 84.7% after 50 cycles at 500mAg−1. This work opens up an avenue to craft the Si/C composite with high volumetric energy densities and rate performance.