β‐Co(OH)₂ Nanosheets: A Superior Pseudocapacitive Electrode for High‐Energy Supercapacitors

Abstract

In this work, β-Co(OH) nanosheets are explored as efficient pseudocapacitive materials for the fabrication of 1.6 V class high-energy supercapacitors in asymmetric fashion. The as-synthesized β-Co(OH) nanosheets displayed an excellent electrochemical performance owing to their unique structure, morphology, and reversible reaction kinetics (fast faradic reaction) in both the three-electrode and asymmetric configuration (with activated carbon, AC). For example, in the three-electrode set-up, β-Co(OH) exhibits a high specific capacitance of ∼675 F g at a scan rate of 1 mV s . In the asymmetric supercapacitor, the β-Co(OH) ∥AC cell delivers a maximum energy density of 37.3 Wh kg at a power density of 800 W kg . Even at harsh conditions (8 kW kg ), an energy density of 15.64 Wh kg is registered for the β-Co(OH) ∥AC assembly. Such an impressive performance of β-Co(OH) nanosheets in the asymmetric configuration reveals the emergence of pseudocapacitive electrodes towards the fabrication of high-energy electrochemical charge storage systems.

Co(OH)2@MnO2 nanosheet arrays as hybrid binder-free electrodes for high-performance lithium-ion batteries and supercapacitors

“…The increasing trend in peak current with an increase in the scan rate confirms that the kinetics of interfacial faradic redox reactions and the rates of electronic and ionic transport are rapid enough at the present scan rates [37]. Additionally, the clear redox peaks during charging and discharging, further suggesting the battery-type electrochemical behavior of Co(OH)2@MnO2 NSs arrays electrode [38][39][40]. Fig.…”

Enhancing the Supercapacitive and Superparamagnetic Performances of Iron Oxide Nanoparticles through Yttrium Cations Electro-chemical Doping

“…Hence, extensive researches have been focused to find proper electrode materials for SCs. Pseudocapacitors mainly store charges from reversible redox reactions and generally composed of transition metal oxides/hydroxides like tin oxide 2 , titanium oxide 3 , cobalt oxide 4,5 , nickel oxide [6][7][8] , vanadium oxide 9 , zinc oxide 10 , manganese oxides [11][12][13][14][15] , cobalt hydroxides [16][17][18][19][20] , nickel hydroxides [21][22][23][24][25] and iron oxides [22][23][24][25][26][27][28][29][30][31][32] . This type of SCs could deliver high specific capacitance, but present poor cycle stability.…”

Electrochemical Assessment of As-Deposited Co(OH)2 by Electrochemical Synthesis: The Effect of Synthesis Temperature on Performance

“…The energy metrics of materials tested in a half-cell configuration seeks to present the electrochemical behavior of this battery type of materials in which Faradic contribution in the storage mechanism plays a significant role. Since the Faradic contribution arises in this case from potential dependent redox according to reactions (5) and (6), since Faradic contributions presented in redox materials tend to behave more like a battery-type, the difference and outlooks to choose between a capacity or capacitance measures is suggested [31].…”

“…Meanwhile, the 95 • C as-deposited electrode shows the lowest areal capacity of 10.24 mA h cm −2 , with a small difference in the last cycle of 7.56 mA h cm −2 . The areal capacity drop is associated with the quasi-reversible-type redox pair of the electrodeposited material during ion intercalation in the voltammetric cycling process [31].…”