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 (ZnBi 38 O 60 ) 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 −1 at a current rate of 100 mA g −1 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 −1 after 50 cycles. In-situ diffraction measurements confirm a conversion based alloying mechanism indicating the formation of various compounds such as Bi 2 O 3 , ZnO, Bi, BiLi, BiLi 3 , 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 LiCoO 2 cathode yields a capacity of 130 mAh g −1 at a current rate of 100 mA g −1 after 700 cycles.