Pseudocapacitive Performance of Freestanding Ni<sub>3</sub>V<sub>2</sub>O<sub>8</sub> Nanosheets for High Energy and Power Density Asymmetric Supercapacitors
Dhananjaya Merum, Ramesh Reddy Nallapureddy, Mohan Reddy Pallavolu, Tapas Kumar Mandal, Gutturu Rajasekhara Reddy, Nargish Parvin, Arghya Narayan Banerjee, Sang Woo Joo
Abstract
Binder-free 2D nanosheet Ni3V2O8/Ni-foam (NVO/Ni) and Ni3V2O8 (NVO) nanoparticles were synthesized using a facile hydrothermal technique for electrochemical capacitor applications. Both the NVO and NVO/Ni samples, produced using 1 M LiOH as a reducing agent during the synthesis, belong to the Ni3V2O8 phase. The electrochemical traits of these electrodes revealed that the NVO/Ni electrodes performed significantly better than the 3D NVO electrodes. The NVO/Ni electrode provided a specific capacitance of 1300 F/g at a current density of 1 A/g with high cycling stability (80.62% at 4 A/g) after 7000 cycles due to structural advantages. Moreover, the NVO/Ni//AC asymmetric supercapacitor device delivered a high energy density of 33.2 Wh/kg at a power density of 2.4 kW/kg and high cycling stability over 10,000 cycles in the 1.2 V working potential window. The device also showed a considerably high maximum power density of 7.2 kW/kg at a 13.62 Wh/kg energy density and remained stable even after 10,000 cycles. The energy–power performance depicted nearly 200% power gain over a mere 59% energy expense, indicating its potential applications in practical devices.