Amorphous TiO_2/C Frameworks as Intercalation Pseudocapacitance Anodes for Fast and Durable Sodium Storage

摘要

High rate and long-life sodium-ion batteries (SIBs) are highly desirable for stationary energy storage applications. However, the practical implementations of SIBs are strictly restricted due to the shortage of satisfactory anode materials. In this study, a Fe and N co-doped amorphous TiO2/C composite synthesized by an MOF-derived approach fulfills the demands of kinetics and durability by stimulating intercalation pseudocapacitance. Unlike traditional crystalline materials whose pseudocapacitance behaviors are highly dependent on the surface area and the crystal structure, the amorphous TiO2/C composite shows fast Na+ intercalation/deintercalation independent of the surface area, and it can deliver impressive capacities, decent rate capability, and excellent cyclability. The electrochemical analysis shows that intercalation pseudocapacitance is responsible for the prominent sodium storage performance of the amorphous TiO2/C composite. This work demonstrates that Na+ intercalation can be realized in amorphous structures and is beneficial for the development of extrinsic pseudocapacitive materials.