Morphology and crystallinity-controlled synthesis of etched CoAl LDO/MnO2 hybrid nanoarrays towards high performance supercapacitors

Preparation of two-dimensional hybrid nanoarrays with porous structure and multiple active components is considered as an effective strategy to improve the electrochemical performance of supercapacitors. Herein, etched CoAl LDO/MnO2 was in-situ prepared on Ni foam by a simple hydrothermal process and subsequent alkali etching treatment. The morphologies and structures of synthetic nanocomposites were examined by XRD, SEM, TEM, EDS, BET and XPS. The nanocomposites present unique hybrid nanoarrays in which etched CoAl LDO nanoarrays form a core and worm-like MnO2 nanosheets create a shell. The electrochemical properties of etched CoAl LDO/MnO2 electrodes were examined by CV, CC and cycling tests. The results exhibit an excellent areal specific capacitance of 991 mF cm(-2), desirable rate capability and outstanding cycling stability of 79.87% retention over 10000 cycles. The asymmetric supercapacitor using etched CoAl LDO/MnO2//AG achieves the maximum energy density and power density of 16.6 Wh kg(-1) and 5000 Wkg(-1), respectively. The excellent electrochemical performance of the as-prepared material suggests its potential application for clean energy storage. (C) 2019 Elsevier B.V. All rights reserved.