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.

Cauliflower-like nanostructured ZnV_(2)S_(4)as a potential cathode material to boost-up high capacity and durability of the aqueous zinc-ion battery

Owing to their unique design and development,high safety and low-cost efficient cathode is still at the forefront of research for rechargeable zinc-ion batteries.However,the suitable cathode operating with ultrahigh capacity with a dendrite-free anode reaction mechanism remains challenging.In this,the first archetype of a high-rate and morphologically stabled cathode material is constructed from novel cauliflower-like nano-ZnV_(2)S_(4)for aqueous zinc-ion batteries.Thus,nano-ZnV_(2)S_(4)was prepared with an anion exchange reaction using ZnV2(OH)8 cauliflower-like nanostructured array as a template interestingly no morphological and shape changes were detected.The as-prepared nano-ZnV_(2)S_(4)electrode reveals a specific discharge capacity of 348.2 mAh/g during 0.5 A/g with enhanced rate capability and excellent capacity retention of 89.2%at 4 A/g current density even after completing 1000 cycles.