Ag-integrated mixed metallic Co-Fe-Ni-Mn hydroxide composite as advanced electrode for high-performance hybrid supercapacitors

Abstract

Direct growth of redox-active noble metals and rational design of multifunctional electrochemical active materials play crucial roles in developing novel electrode materials for energy storage devices. In this regard, silver (Ag) has attracted great attention in the design of efficient electrodes. Inspired by the house/building process, which means electing the right land, it lays a strong foundation and building essential columns for a complex structure. Herein, we report the construction of multifaceted heterostructure cobalt-iron hydroxide (CFOH) nanowires (NWs)@nickel cobalt manganese hydroxides and/or hydrate (NCMOH) nanosheets (NSs) on the Ag-deposited nickel foam and carbon cloth (i.e., Ag/NF and Ag/CC) substrates. Moreover, the formation and charge storage mechanism of Ag are described, and these contribute to good conductive and redox chemistry features. The switching architectural integrity of metal and redox materials on metallic frames may significantly boost charge storage and rate performance with noticeable drop in resistance. The as-fabricated Ag@CFOH@NCMOH/NF electrode delivered superior areal capacity value of 2081.9 µA h cm⁻² at 5 mA cm⁻². Moreover, as-assembled hybrid cell based on NF (HC/NF) device exhibited remarkable areal capacity value of 1.82 mA h cm⁻² at 5 mA cm⁻² with excellent rate capability of 74.77% even at 70 mA cm⁻² Furthermore, HC/NF device achieved maximum energy and power densities of 1.39 mW h cm⁻² and 42.35 mW cm⁻², respectively. To verify practical applicability, both devices were also tested to serve as a self-charging station for various portable electronic devices.