One Step Hydrothermal Confined Growth of Ni 3 V 2 O 8 on 3D GO/CNT Networks Toward High‐Performance Supercapacitors

Binary transition metal oxides attract extensive attention due to outstanding electrochemical charge‐storage performance. As a typical bimetallic oxide, nickel vanadate (Ni 3 V 2 O 8 ) possesses rich multivalent Ni/V redox sites and delivers high theoretical capacitance for supercapacitor electrodes. Herein, ternary Ni 3 V 2 O 8 /GO/CNT was successfully fabricated via a facile one‐step hydrothermal strategy. GO and CNT self‐assemble into an interconnected 3D dual‐carbon network via van der Waals forces and π‐π stacking, which confines uniform in situ growth of Ni 3 V 2 O 8 particles. The synergistic structural and conductive advantages endow the optimized Ni 3 V 2 O 8 /GO/CNT electrode with a high specific capacitance of 882.5 F g − 1 at 0.5 A g − 1 . Coin‐cell symmetric supercapacitors (SSCs) were further assembled to evaluate the practical application potential of the Ni 3 V 2 O 8 /GO/CNT. The SSC device works steadily at 0–1.5 V in 3 m KOH aqueous electrolyte, achieves a specific capacitance of 194.3 F g − 1 at 0.5 A g − 1 , and exhibits a maximum energy density of 36.8 Wh kg − 1 at a power density of 375.2 W kg − 1 . After 6000 charge‐discharge cycles, the device retains 89.6% of its initial capacitance, demonstrating excellent long‐term cycling stability. Two series‐connected coin cells successfully power a 2 V LED lamp, verifying its great potential for practical energy storage.