LiFePO4/reduced graphene oxide hybrid cathode for lithium ion battery with outstanding rate performance

Abstract

A lithium iron phosphate (LFP)/reduced graphene oxide (rGO) hybrid has been prepared using a homogeneous coprecipitation method followed by heat treatment. As a cathode material for the lithium ion battery, the hybrid demonstrates a specific capacity higher than 170 mA h g⁻¹. The excess capacity of more than the theoretical value of LFP is attributed to the reversible reduction–oxidation reaction between lithium ions and rGO nanosheets. The highly conductive rGO sheets upon which LFP particles are uniformly and closely anchored assist in the electron migration and lithium ion transfer and prevent the aggregation of LFP particles during charging and discharging, leading to an initial coulombic efficiency of more than 100% with the content of rGO between 7% and 25% in the hybrid. LFP with 15% rGO shows a high discharge capacity of 172 mA h g⁻¹ at 0.06 C, and the capacity remains 139 mA h g⁻¹ at 11.8 C, in addition to showing an excellent cycling stability.