Growth of CoMn-LDH/Co-Ni bimetallic sulfides on nickel foam with enhanced electrochemical properties for asymmetric supercapacitors
Feng Xiao, Rong Su, Luyao Zhang, Lu Yang, Zeyi Wang, Yu Jiang, Lichuan Chen, Chao Chen, Ke Li, Bin Tang, Ping He
Abstract
Incorporating transition metal sulfide with layered double hydroxide to form the heterostructure is a valid strategy, which helps to reduce volume expansion of active substances during long charging and discharging and enhance diffusion rate of ion. Herein, cobalt-nickel bimetallic sulfides and cobalt-manganese layered double hydroxide composite on nickel foam (CM/CNS/NF) is prepared by hydrothermal method combined with electrodeposition . The structure, morphology and electrochemical characterizations of as-prepared CM/CNS/NF electrodes are studied systematically. The results show that electrochemical properties of CM/CNS/NF electrodes vary with molar ratio of CoCl 2 ·6H 2 O and MnCl 2 ·4H 2 O (1:1, 3:1, 5:1 and 7:1). When the molar ratio of CoCl 2 ·6H 2 O and MnCl 2 ·4H 2 O is 3:1, CM/CNS/NF is equipped with high specific capacity of 934.0 C g −1 at 1 A g −1 . In addition, its retention rate of capacity can still remain 75.27% after 3000 cycles at 20 A g −1 . Moreover, when power density is 800 W kg −1 , energy density of the asymmetric device composed of positive electrode (CM/CNS/NF) and negative electrode (activated carbon/NF) is as high as 37.53 Wh kg −1 . These results show that design and preparation of CM/CNS/NF provide a route to elevate specific capacity for potential application in the field of supercapacitors .