Pseudocapacitive Zinc Cation Intercalation with Superior Kinetics Enabled by Atomically Thin V₂O₅ Nanobelts for Quasi-Solid-State Microbatteries

Given that the booming development of smart wearable, miniaturized and integrated electronics, rechargeable zinc ion batteries (ZIBs) have shown immense advantage in this field on account of high safety, abundant zinc reserves and environmentally friendly. However, appropriate cathodes materials that show high capacity and rate capability for high-perfromance microbatteries are still scarce. Herein, atomically thin V₂O₅ nanobelt (∼2 nm thickness) with layered crystal structure are first investigated as the cathode of ZIBs. V₂O₅@CNTs flexible electrodes are subsequently constructed by combining the V₂O₅ nanobelts and carbon nanotubes (CNTs). The interpenetrating network in the electrode formed by the one-dimensional (1D) nanoblets and nanotubes ensures fast electronic and ionic transport. Meanwhile, considering the unique thickness and crystal feature of V₂O₅ nanobelts, it provides great chance for the electrode to realize large intercalation pseudocapacitance. As a results, V₂O₅@CNTs hybrid film electrode exhibits ultrahigh capacity of 485.8 mAh g ^{− 1} at 0.1 A g ^{− 1}, admirable rate capability of 137.6 mAh g ^{− 1} at 50 A g ^{− 1}, as well as large energy density of 352 Wh kg⁻¹. Further, V₂O₅@CNTs cathode were assembled in quasi-solid-state zinc ion microbatteries (ZIMBs), and exhibits excellent electrochemical performance of 112.5μWh cm⁻², demonstrating great potential in microsized energy storage devices.