In Situ Growth of Layered Bimetallic ZnCo Hydroxide Nanosheets for High-Performance All-Solid-State Pseudocapacitor

Abstract

Two-dimensional (2D) hydroxide nanosheets can exhibit exceptional electrochemical performance owing to their shortened ion diffusion distances, abundant active sites, and various valence states. Herein, we report ZnCo(OH)Cl·0.45HO nanosheets (thickness ∼30 nm) which crystallize in a layered structure and exhibit a high specific capacitance of 3946.5 F g at 3 A g for an electrochemical pseudocapacitor. ZnCo(OH)Cl·0.45HO was synthesized by a homogeneous precipitation method and spontaneously crystallized into 2D nanosheets in well-defined hexagonal morphology with crystal structure revealed by synchrotron X-ray powder diffraction data analysis. In situ growth of ZnCo(OH)Cl·0.45HO nanosheet arrays on conductive Ni foam substrate was successfully realized. Asymmetric supercapacitors based on ZnCo(OH)Cl·0.45HO nanosheets @Ni foam// PVA, KOH//reduced graphene oxide exhibits a high energy density of 114.8 Wh kg at an average power density of 643.8 W kg, which surpasses most of the reported all-solid-state supercapacitors based on carbonaceous materials, transition metal oxides/hydroxides, and MXenes. Furthermore, a supercapacitor constructed from ZnCo(OH)Cl·0.45HO nanosheets@PET substrate shows excellent flexibility and mechanical stability. This study provides layered bimetallic hydroxide nanosheets as promising electroactive materials for flexible, solid-state energy storage devices, presenting the best reported performance to date.

Porous Ultrathin NiSe Nanosheet Networks on Nickel Foam for High‐Performance Hybrid Supercapacitors

“…Fossil fuel shortage, environmental pollutiona nd the imminent and extensive application of renewable energy have stimulated worldwide interesti ne nvironmentally friendly and highperformance electrochemical energy storage devices. [1][2][3] Supercapacitors (SCs),w hich possess significant advantages such as ultrahighp owerd ensity and long cycle life, have been considered as the most promising energy storages ystems for portable electronics,e lectric and hybrid vehicles,a nd energy harvesting. [4][5][6] However,t he relativelyl ow energy densities of SCs severelyr estrict their commerciala pplications.…”

“…Herein, we report the development of am ethod for the synthesis of 3D porous ultrathin NiSe nanosheets networks (put-NiSe NNs) on nickel foam for high-performanceH SC. Mndoped a-Ni(OH) 2 nanosheet networks were first fabricatedo n nickel foam based on the distinct solubility of Ni(OH) 2 and Mn(OH) 2 in weakly alkaline solution, [32] and subsequently treated by one step of selenylation plus pickling (Scheme 1). Removal of Mn led to the formation of highly porous nanosheets.…”

“…SEM images of (a-c) the Mn-doped a-Ni(OH)2 and (d-f)t he put-NiSeNNs.ChemSusChem 2020, 13,260 -266 www.chemsuschem.org proximately 5nm. The crystal structures of the nanocrystallites were explored by high-resolution TEM (HRTEM,Figure 2d).…”

Preparation of macroporous transition metal hydroxide monoliths via a sol-gel process accompanied by phase separation

“…Transition metal hydroxides have special functional groups and distinctive structures, and possess high adsorption capacity to polar substances and excellent performance in adsorbing harmful and contaminant materials 1 , water splitting 2 and supercapacitor 3 in the field of energy 4 , catalysis 5 and environment, etc. Up to now, two dimensional structural transition metal hydroxides such as thin film, layer 6,7 or sheet 2 , have been synthesized by numerous techniques.…”

All Hierarchical Core–Shell Heterostructures as Novel Binder‐Free Electrode Materials for Ultrahigh‐Energy‐Density Wearable Asymmetric Supercapacitors

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Supercapacitors (SCs), especially fiber-shaped supercapacitors (FSCs) with their tiny volume, remarkable flexibility, and excellent stitchability as well as fast charge-discharge capability, a high power density, and a long cycle life, are promising energy storage and supply devices. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Supercapacitors (SCs), especially fiber-shaped supercapacitors (FSCs) with their tiny volume, remarkable flexibility, and excellent stitchability as well as fast charge-discharge capability, a high power density, and a long cycle life, are promising energy storage and supply devices.…”