Electrospun Fe2TiO5-TiO2@Graphene Nanofibers as Highly Durable Insertion Anode with Enhanced Lithium Storage Properties

摘要

Iron titanate is of considerable interest as a potential anode material for electrochemical energy storage and conversion. Herein, a fiber-like Fe2TiO5-TiO2@graphene (rGO-FTO-TO) hybrid structure is rationally designed and delicately fabricated by anchoring reduced graphene oxide (rGO) nanosheets on Fe2TiO5-TiO2 (FTO-TO) nanofibers. The effective wrapping of rGO nanosheets can greatly improve the electrical conductivity and reduce the volume expansion. When evaluated as an anode, the rGO-FTO-TO exhibits remarkable lithium storage properties in terms of high capacity, long-term cycling stability, and excellent rate capability. Moreover, there exists a strong electrostatic interaction between rGO nanosheets and FTO-TO nanofibers by the introduction of aminopropyltriethoxysilane to induce the immobilization of a positively charged -NH3+ group on the FTO-TO surface, promoting the bonding with negatively charged carboxylic acid (-COO-) and hydroxyl (-OH) groups on the rGO. With strong electrostatic interaction, the rGO-FTO-TO exhibits appreciably enhanced initial capacity, elevated capacity retention, and high columbic efficiency compared with those of pristine FTO-TO nanofibers. This work provides a feasible strategy for fabricating a graphene-encapsulated FTO-TO fiber-like composite as a promising high-performance anode for lithium-ion batteries.