Pseudocapacitive Performance of Freestanding Ni₃V₂O₈ Nanosheets for High Energy and Power Density Asymmetric Supercapacitors

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.

Engineering cationic vacancies on sphere-like zinc cobaltite microstructuresviaself-assembly of silkworm-like interconnected nanoparticles for battery-type supercapacitors

“…Zinc cobaltite (ZnCo 2 O 4 ; ZCO) is a promising material that has a wide range of applications in various fields. Some of the uses of ZCO synthesis include catalysis, 18 energy storage (supercapacitors, batteries, and fuel cells), 9 gas sensing 19 and magnetic materials. 20 ZCO is an outstanding competitor for battery-type supercapacitors due to its abundance, low toxicity, distinctive composition, high theoretical specific capacity, extensive redox chemistry, and synergistic effects of the Zn and Co metal cations.…”

“…8 Consequently, supercapacitors have found extensive applications in load-level cranes, memory backup systems, electric vehicles, microelectronics, and other fields. 9 Electrode materials are crucial in determining the performance of supercapacitors, which can be categorized into three types based on their charge-storage mechanisms. 10 Firstly, there is electric double-layer capacitor (EDLC)-based materials that store charge on an electric double layer between the electrode surface and electrolyte through physical absorption/desorption.…”

A Foldable Aqueous Zn‐Ion Battery with Gear‐Structured Composite as Freestanding Cathode

“…The peaks at 283, 405, 523 and 699 cm À 1 correspond to the bending vibrations of OÀ VÀ O, VÀ O and VÀ OÀ V, and the stretching vibration of VÀ O in the double-layer V 2 O 5 chain, respectively. [20] In our composite design, the integrated 3D gear-like configuration greatly increases the mechanical flexibility. In parallel, the large surface area and the wide inter-spacing of the gear blades increase Zn 2 + contact area and reduce the Zn 2 + diffusion pathway, which results in an obviously increased ionic conductivity.…”

“…The low‐frequency peak at 143 cm −1 is originated from the bending vibration of the skeleton, which is related to the lamellar structure. The peaks at 283, 405, 523 and 699 cm −1 correspond to the bending vibrations of O−V−O, V−O and V−O−V, and the stretching vibration of V−O in the double‐layer V 2 O 5 chain, respectively [20] …”

Revealing the electrochemical performance of a manganese phosphite/RGO hybrid in acidic media

“…An AC frequency range of 100 kHz to 10 mHz, along with an AC amplitude of 5 mV, was applied for the electrochemical impedance spectroscopy (EIS). The specific capacitance, energy density and power density of the material were calculated by using the following equations: 36–38 C sp = I m /(d V /d t )Energy density (E.D.) = C sp × (Δ V ) 2 /(2 × 3.6)Power density(P.D.)…”