摘要
Supercapacitors are electrochemical energy storage devices with great potential applications.Mean-while,the oxygen evolution reaction(OER)determines the efficiency of some electrochemical energy conversions.This study aims at constructing,exploring,and optimizing Ramsdellite-MnO_(2)@NiCoAl-LDH@CC(R-MNCA@CC)composites.The effect of microstructure and Al role on the performance is investigated when R-MNCA@CC was used as supercapacitor electrode material and OER catalyst.Coral-like R-MNCA@CC in-situ growth composites were synthesized by a two-step hydrothermal method.R-MNCA@CC-2(molar ratio of Ni:Co:Al is 1:1:1)performs the best with the largest specific capacitance,1,742 F/g at 1 A/g,increased by 797%and 1,489%compared to that of NiCoAl-LDH and Ramsdellite-MnO_(2).The capacitance retention rate of the R-MNCA@CC-2//AC@CC supercapacitor is 80.1%after 5,000 cycles at 0.8 A/g.The overpotential for driving an OER to reach 10 m/cm^(2)is only 276 mV,which is lower than that of commercial IrO_(2)(300 mV).Noteworthy,we propose a view that is“competing to trigger redox re-action”of electrochemical active sites in LDH during electrochemical processes derived from a discrepancy between theory and experimental results.
基金
Great appreciation for the support of the funding of the Key R&D Program of Zhenjiang(GY201816)
Student Innovation Project of Jiangsu University(22A030).
