Stoichiometric Ternary Metal Oxide, ZnBi38O60 - Reduced Graphene Oxide Composite for Stable and High-Rate Li-Ion Storage

Mixed transition metal oxides exhibit enormous potential as compared to traditional individual metal oxides for energy storage devices such as metal-ion batteries. In the present study, a composite based on a mixed ternary oxide based on zinc and bismuth (ZnBi38O60) and rGO was explored as an anode material for rechargeable Li ion battery. Pristine metal oxide and the composite were thoroughly characterized using different physicochemical techniques and the phase-pure materials were used to study their lithium storage properties. The composite shows a very stable capacity of 415 mAh/g at a current rate of 100 mA/g at the end of 1000 cycles in contrast to pristine metal oxide that reveals a continuous decrease in capacity and drops down to 53 mAh/g after 50 cycles. In-situ diffraction measurements confirm a conversion based alloying mechanism indicating the formation of various compounds such as Bi2O3, ZnO, Bi, BiLi, BiLi3, and ZnLi at different stages of discharge and charge process. The composition and thickness of the solid electrolyte interphase was probed by X-ray photoelectron spectroscopy at different depths of argon sputtering. A full cell with the composite anode and LiCoO2 cathode yields a capacity of 130 mAh/g at a current rate of 100 mA/g after 700 cycles