Exploration of V2O5 nanorod@rGO heterostructure as potential cathode material for potassium-ion batteries

Highlights: • V₂O₅@rGO is shown to be a suitable cathode for nonaqueous K-ion batteries. • V₂O₅@rGO exhibits the highest reversible capacity for a K-ion battery to date. • V₂O₅@rGO shows good rate capability and very good capacity retention over many cycles. • The structure of V₂O₅@rGO composite is stable even after 500 cycles. -- Abstract: Potassium-ion batteries (KIBs) are considered as an alternative energy storage device for lithium-ion batteries (LIBs) owing to the low cost and earth abundant. Herein, first time we report the hydrothermally synthesized Bacilli rod shape V₂O₅ and making composite with reduced graphene oxide (rGO) for KIBs which greatly boosting the cycle durability and rate capability. Sheet-like materials (rGO) greatly enhance the performance of energy storage materials due to their high surface area which largely improves the electrochemical reaction kinetics. The heterostructure of V₂O₅ nanorods anchored on highly conductive rGO matrix not only enhance the reaction kinetics but also offer a more reactive surface area for potassium-ion storage resulting superior cycling stability. The V₂O₅@rGO exhibits a reversible capacity of 271 mAhg⁻¹ and retains 80% initial discharge capacity after 500 cycles. It shows excellent rate capability and delivers 50 mAhg⁻¹ even at the high current density of 2940 mAg⁻¹ (10C). Ex-situ TEM and XRD analysis confirmed that the rod-shape with sheet like rGO morphology is retained after 500 cycles. The design of nanorod@sheet like architecture becomes a promising cathode candidate for high performance KIBs.