Supercapacitive Performances of Single‐Phase Quaternary Metal Hydroxychlorides

Abstract

Metal hydroxychloride, as a new electrode material, shows an excellent electrochemical performance owing to the presence of abundant Cl À ions and hydroxyl groups. Herein, a singlephase quaternary M 2 (OH) 3 Cl based composite is constructed, for the first time, via a simple deep eutectic solvent annealing process, followed by the exposure to air at ambient temperature. Herein, this composite, denoted as M 2 (OH) 3 Cl-4/CoNi/ NÀ C, is made up of ultrafine M 2 (OH) 3 Cl nanoparticles composed of Mn 2 + , Fe 2 + , Co 2 + and Ni 2 + , CoNi alloy nanoparticles and N-doped carbon with a degree of graphitization. M 2 (OH) 3 Cl-4/ CoNi/NÀ C exhibits an excellent specific capacitance of 1576.6 F g À 1 at 0.5 A g À 1 , exceeding the unary, binary and ternary metal hydroxychlorides, which is attributed to the synergistic effect among the four metals in M 2 (OH) 3 Cl and the formation of CoNi alloy nanoparticles and carbon substrates. Our findings offer promise for creating unique functional materials via combining multiple components with distinctive properties.