Extremely stable cycling of ultra-thin V₂O₅ nanowire-graphene electrodes for lithium rechargeable battery cathodes

Vanadium pentoxide (V₂O₅) has received considerable attention as a lithium battery cathode because its specific capacity (>250 mA h g^-1) is higher than those (<170 mA h g^-1) of most commercial cathode materials. Despite this conspicuous advantage, V ₂O₅ has suffered from limited cycle life, typically below a couple of hundred cycles due to the agglomeration of its particles. Once V₂O₅ particles are agglomerated, the insulating phases continuously expand to an extent that ionic and electronic conduction is severely deteriorated, leading to the significant capacity decay. In this study, in order to overcome the agglomeration issue, the electrodes were uniquely designed such that ultrathin V₂O₅ nanowires were uniformly incorporated into graphene paper. In this composite structure, the dispersion of V₂O₅ nanowires was preserved in a robust manner, and, as a result, enabled substantially improved cycle life: decent specific capacities were preserved over 100 000 cycles, which are 2-3 orders of magnitude larger than those of typical battery materials.