Core-shell manganese cobalt oxide‑nickel molybdenum layered double hydroxide composites for supercapacitor electrodes
Ying Wu, Qing Xue, Youjuan Cao, Bin Geng, Yongjin Zou, Cuili Xiang, Fen Xu, Lixian Sun
Abstract
The electrochemical performance of electrodes for high-energy density supercapacitors is significantly enhanced by using a core-shell composite comprised of layered double hydroxides (LDHs) combined with metal oxides. In this study, a core-shell composite, MnCo₂O₄@NiMo-LDH, was successfully synthesized, characterized, and applied as an electrode. MnCo 2 O 4 was first prepared using calcination and hydrothermal treatment techniques, then MnCo 2 O 4 @NiMo-LDH was prepared using a hydrothermal treatment process. The specific capacitance of MnCo 2 O 4 @NiMo-LDH at 1 A g −1 is 1009 F g −1 . An asymmetric supercapacitor (ASC) assembled using MnCo 2 O 4 @NiMo-LDH electrodes achieved an energy density of 43.2 Wh kg −1 at a power density of 815.8 W kg −1 . Density functional theory (DFT) calculations confirmed that structural and electronic reconstructions occur at the MnCo 2 O 4 @NiMo-LDH interface, enhancing reaction kinetics and improving electrochemical performance. The ASC with MnCo 2 O 4 @NiMo-LDH electrodes exhibited a capacitance retention of 71 % after 5000 cycles, demonstrating excellent long-term cycling stability. The MnCo 2 O 4 @NiMo-LDH electrode exhibits remarkable performance in energy storage applications, highlighting its potential for practical implementation.