CuFeS2 anchored in ethylenediamine-modified reduced graphene oxide as an anode material for sodium ion batteries

Tetragonal CuFeS2 anchored in ethylenediamine-modified reduced graphene oxide (CuFeS2/EN-rGO) was synthesized via a simple solvothermal method, and evaluated for the first time as an anode material for sodium ion batteries via constant current charge/discharge, rate charge/discharge, cyclic voltammetry, electrochemical impedance spectroscopy. Ex-situ XRD revealed sodium storage mechanism of CuFeS2, indicating that its capacity is mainly provided by the conversion reaction. Compared with CuFeS2, reversible capacity and cycle performance of CuFeS2/EN-rGO was significantly improved by high electrical conductivity of EN-rGO. At 1.0 A g-1, the discharge capacity of CuFeS2/EN-rGO maintained 247.8 mAh g-1 at 250th cycle, corresponding to 0.14% discharge capacity decay rate per cycle compared with its second discharge capacity. Even at 3.2 A g-1, it can reached a discharge capacity of 296.2 mAh g-1. The results show that CuFeS2/EN-rGO has certain development prospects as an anode material for sodium ion batteries.