Reinvigorating Reverse-Osmosis Membrane Technology to Stabilize the V₂O₅ Lithium-Ion Battery Cathode

V₂O₅ is deemed as one of the most promising cathode materials for next-generation high-capacity lithium-ion batteries (LIBs). It possesses a theoretical capacity of 294 mAh g⁻¹, which is much higher than conventional cathodes. However, there are many issues to be solved before its practical use, including poor cycle life and unsatisfactory rate performance, mainly owing to its low electronic conductivity and ionic diffusivity, as well as structural instability. This work reports three types of V₂O₅ asymmetric membranes synthesized by using an adapted reverse-osmosis membrane technology combined with sol-gel chemistry, aiming to stabilize the cyclability and improve the rate performance. V₂O₅ asymmetric membrane cathodes prepared using graphene as the conductive additives have a specific capacity of approximately 160 mAh g⁻¹ at a current density of 100 mA g⁻¹ with no capacity degradation after 380 cycles. It is also found that the annealing temperature and the choice of conductive additives can affect the morphology of V₂O₅ nanoparticles and the overall electrode cyclability. A lower annealing temperature (300 vs. 400 °C) and addition of graphene are beneficial to long-term cycling performance.