Crumpled reduced graphene oxide conformally encapsulated hollow V2O5 nano/microsphere achieving brilliant lithium storage performance

It has remained a challenge to develop a facile and scalable approach to synthesize high-energy lithium-ion battery (LIB) electrode materials with excellent rate capabilities and prominent cycling stabilities for their applications in new generation energy storage devices. In this study, for the first time, we report a crumpled reduced graphene oxide (cG) encapsulated three-dimensional (3D) hollow vanadium pentoxide (V2O5) nano/microspheres fabricated by one-step solvothermal treatment followed by subsequent annealing. This rapid and effective synthesis method is environmental friendly and economically beneficial without involving costly organic vanadium sources, tedious operation, or sophisticated equipment. Remarkably, the desired cG-encapsulated V2O5 composite contains 5 wt% reduced graphene oxide (rGO), yet exhibits outstanding rate capacities and cycling stabilities. This product can deliver reversible capacities of 289 mA h g(-1) at 100 mA g(-1) and 163 mA h g(-1) at 5000 mA g(-1) (492 W h kg(-1) and 9840 W kg(-1)), as well as a capacity retention of about 94% after 200 cycles at 2000 mA g(-1) in the potential range between 2.0 V and 4.0 V (vs. Li/Li+). Furthermore, the unique structural feature and typical formation mechanism of the designed materials are clarified based on multiple experimental results. More commendably, a chain of solid powders had been successfully encapsulated using this scalable reaction system. It is expected that this versatile approach will facilitate the applications of cG, and provide a novel avenue to create more fascinating rGO-based functional materials. (C) 2016 Elsevier Ltd. All rights reserved.