V₂O₅ nanoparticles confined in Three−Dimensionally organized, porous Nitrogen−Doped graphene frameworks: Flexible and Free−Standing cathodes for high performance lithium storage

Nowadays, lithium−ion batteries (LIBs) are attracting great interest for energy storage applications ranging from small−size cell phones to large−size electric vehicles. Among different cathode materials which have been widely investigated, vanadium pentoxide (V₂O₅) is particularly attractive because of its high specific capacity and low cost. However, drawbacks such as low electronic conductivity and poor ion diffusion kinetics restrict its further applications in large−size electric vehicles. In this work, we report a one−step hydrothermal strategy to integrate nitrogen doping, aerogel formation and V₂O₅ loading on graphene nanosheets simultaneously. The introduction of 3D nitrogen−doped graphene (3DNG) can provide higher electronic conductivity and Li⁺ ion diffusion kinetics. The resulting V₂O₅@3DNG aerogels can be used as cathodes directly without any binders, conductive additives and metallic collectors. The free−standing and flexible cathodes can effectively promote rapid capacity response and buffer the stress generated during the high−rate charging/discharging processes, which are responsible for superior cyclability and rate capabilities. This strategy may provide new insight into the improvements of LIB performances.