A modified reduced graphite oxide anode for sodium ion storage in ether‐based electrolyte

Abstract

In this work, reduced graphite oxide (rGO) with a long-range-ordered layered structure and an expanded interlayer spacing is synthesized and utilized as an anode for sodium ion storage. Unlike Na+-solvent co-intercalation in flake graphite, the interaction between Na-ions and graphene layers of the rGO shows a capacitive behavior. All the surface defects, pores, and functional groups generated on the surface of rGO can contribute to additional capacity of sodium storage. Thereby, a reversible capacity of 145.7 mAh g−1 at 1 A g−1 and a rate performance of 131.7 mAh g−1 at 1.8 A g−1 could be obtained. Capacity retention of 87.7 % after 900 cycles at 400 mA g−1 was also achieved. Further enhancement in cycling stability, with little capacity decay after 1500 cycles, was obtained after incorporating Ag onto the surface of the rGO. The rGO-Ag anode delivered higher energy density and power density as compared to rGO at the same current density. Even at a power density of 5493 W kg−1 (3A g−1, 24 C), the energy density was as high as 236.2 Wh kg−1. These results contribute to the development of a low-cost, high-performance sodium ion storage devices.