Microwave-assisted solvothermal synthesis and electrochemical characterizations of ternary perovskite NiTiO3 anode materials for lithium-ion batteries

Abstract

Perovskite-structured NiTiO3 powders were synthesized via the microwave-assisted solvothermal and conventional solvothermal processes for the application of anode materials in Li-ion batteries. In the conventional solvothermal process, a pure perovskite phase was not achieved, and a TiO2 impurity phase existed. Whereas, pure perovskite NiTiO3 powder with a rhombohedral structure was successfully synthesized using the microwave-assisted solvothermal process. The developed microwave-assisted process considerably reduced the total required heating time for preparing the pure perovskite phase. In both processes, the obtained powders displayed micro-rod shaped morphology. Electrochemical analysis showed high specific discharge capacity (750 mAh/g) at a current density of 0.1C and promising capacity retention (177 mAh/g) after the 90th cycle, with a coulombic efficiency of 90%. By comparison, the sample synthesized through the conventional approach delivered a lower specific discharge capacity of 737 mAh/g at a current density of 0.1C. Electrochemical impedance spectroscopy analysis indicated that the charge-transfer resistance Rct values of NiTiO3 powder synthesized using the microwave-assisted and conventional approaches were 16 and 23 Ω, respectively. The improved electrochemical performances and lower Rct values could be ascribed to the improved crystallinity and surface morphology of NiTiO3 powders derived from the microwave process. The present research indicated that the microwave-assisted solvothermal synthesis is a potential approach to synthesize NiTiO3 anode materials for high-performance lithium-ion batteries.