Research progress in rare earths and their composites based electrode materials for supercapacitors

Supercapacitor is an imminent potential energy storage system, and acts as a booster to the batteries and fuel cells to provide necessary power density. In the last decade, carbon and carbonaceous materials, conducting polymers and transition metal oxide/hydroxide based electrode materials have been made to show a remarkable electrochemical performance. Rare-earth materials have attracted significant research attention as an electrode material for supercapacitor applications based on their physicochemical properties. In this review, rare earth metals, rare earth metal oxides/hydroxides, rare-earth metal chalcogenides, rare-earth metal/carbon composites and rare-earth metal/metal oxide composites based electrode materials are discussed for supercapacitors. We also discuss the energy chemistry of rare-earth metal-based materials. Besides the factors that affect the performance of the electrode materials, their evaluation methods and supercapacitor performances are discussed in details. Finally, the future outlook in rare-earth-based electrode materials is revealed towards its current developments for supercapacitor applications. (C) 2020, Institute of Process Engineering, Chinese Academy of Sciences. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.