Binary Nickel–Cobalt Oxides Electrode Materials for High-Performance Supercapacitors: Influence of its Composition and Porous Nature

Abstract

Nickel-cobalt oxides were prepared by coprecipitation of their hydroxides precursors and a following thermal treatment under a moderate temperature. The preformed nickel-cobalt bimetallic hydroxide exhibited a flower-like morphology with single crystalline nature and composed of many interconnected nanosheets. The ratio of Ni to Co in the oxides could easily be controlled by adjusting the composition of the original reactants for the preparation of hydroxide precursors. It was found that both the molecular ratio of Ni to Co and the annealing temperature had significant effects on their porous structure and electrochemical properties. The effect of the Ni/Co ratio on the pseudocapacitive properties of the binary oxide was investigated in this work. The binary metal oxide with the exact molar ratio of Ni:Co = 0.8:1 annealed at 300 °C, showing an optimum specific capacitance of 750 F/g. However, too high an annealing temperature would lead to a large crystal size, a low specific surface area, as well as a much lower pore volume. With the use of the binary metal oxide with Ni:Co = 0.8:1 and activated carbon as the positive and negative electrode, respectively, the assembled hybrid capacitor could exhibit a high-energy density of 34.9 Wh/kg at the power density of 875 W/kg and long cycling life (86.4% retention of the initial value after 10000 cycles).

Vastly Enhanced BiVO4 Photocatalytic OER Performance by NiCoO2 as Cocatalyst

“…47‐1049) and Co 3 O 4 (JCPDS No. 43‐1003) are also synthesized in this study (Figure S12b, Supporting Information) and used as OER cocatalysts for the purpose of comparison.…”

Strategic Preparation of Efficient and Durable NiCo Alloy Supported N‐Doped Porous Graphene as an Oxygen Evolution Electrocatalyst: A Theoretical and Experimental Investigation

“…However, NiCo/pNGr(75:25) shows two broad anodic peaks at around 1.34 and 1.39 V and the corresponding cathodic peaks at around 1.20 and 1.28 V, respectively. Because of the very close exchange potentials of Co 3+ /Co 4+ and Ni 2+ /Ni 3+ , this broad anodic peak can be correlated to the M 2+ /M 3+ and M 3+ /M 4+ (M = Co and Ni) couples . The Co 3+ /Co 4+ couple in the CV of Co/pNGr sample is having less intensity at higher potential of nearly 1.2 V (vs RHE).…”

Tunability of Porous CuCo2O4 Architectures as High‐Performance Electrode Materials for Supercapacitors

“…All the CuCo 2 O 4 porous structures with diverse shapes are induced from the specific amounts of the structure directing agent PVP. Additionally, the pores are embedded into this structures by the annealing process because the organic molecule (PVP) was removed at 320 °C giving rise to the evolution of ammonia gas . These pores are beneficial to enhance the electrochemical reaction of the electrode by working as active sites in accord to increase the transport efficiency of the electron/ion in the electrode.…”