Partial hydrothermal sulfidation of electrosynthesized Co-Mn layered-double-hydroxide as an active material for supercapacitor applications

This work describes a partial sulfidation approach to establish a CoMn-Layered double hydroxide (LDH)/CoMn-S heterostructure on nickel foam (NF) (CoMn-LDH/CoMn-S/NF). The partially sulfurized CoMn-LDH/CoMn-S/NF electrode exhibits significantly higher electrical conductivity and a significant improvement in electrochemical performance in comparison to both CoMn-LDH and fully sulfurized CoMn-S. The CoMn-LDH/CoMn-S/NF electrode demonstrates a significant specific capacity of 792.4 C g−1 at a current density of 1 A g−1. The evaluation results show that the synthesized heterostructures have good potential for use in supercapacitors by establishing an asymmetric supercapacitor (ASC) device. By assembling the ASC device using CoMn-LDH/CoMn-S/NF and Electric Double Layer Capacitors (EDLC) type (activated carbon) materials, it can demonstrate an energy density in the range of 82.63 to 24.4 Wh kg−1 and a power density of 985–10998 W kg−1. Achieving a cycling stability of 94 % after 6000 charge-discharge cycles is a remarkable feat, demonstrating the substantial potential for ACS devices. A calculation utilizing the density functional theory indicates that the CoMn-LDH/CoMn-S/NF electrode expedites charge transfer and improves electronic conductivity, guaranteeing a spectacular electrochemical performance. The results may provide a successful method for the creation of battery-like heterostructure electrodes with cutting-edge charge-transfer structures for supercapacitor applications. © 2024 Elsevier B.V.