Influence of the Sn(Fe)–C bonds content in SnFe2O4@reduced graphene oxide composites on the electrochemical behavior of lithium-ion batteries

Abstract

Inverse spinel SnFe2O4 as an anode material for lithium-ion batteries (LIBs) suffers from poor cycling stability due to its lower conductivity and excess volume change during charge/discharge process. In order to overcome the obstacles, a series of SnFe2O4@reduced graphene oxide (rGO) composites with different amount of Sn(Fe)–C bonds between SnFe2O4 and rGO interface are synthesized through a simple one-pot solvothermal method and subsequent sintering at different temperatures. The composite with higher Sn(Fe)–C bonds content exhibits higher charge/discharge capacities of 1010/1020 mAh g−1 at 0.5 A g−1 for 300 cycles, and a better rate capability of 620 mAh g−1 at 2.0 A g−1. The synergistic effect of larger content of Sn(Fe)–C bonds and the formed flower-like networks between the pulverized SnFe2O4 and the rGO interface during charge/discharge is favor to improve the kinetics of SnFe2O4, because the networks are acted as the transport highway for electronics and lithium-ions. Moreover, the higher content and strong action of Sn(Fe)–C bonds can prevent the SnFe2O4 nanoparticles suffer from excessively volume change and pulverize during cycling. Designing chemically bonded metal oxides with graphene composite could provide a simple way to improve the cycle stability and rate capability of the LIBs.