In situ tellurization strategy for crafting nickel ditelluride/cobalt ditelluride hierarchical nanostructures: A leap forward in hybrid supercapacitor electrode materials

Abstract

Advancements in renewable energy conversion can be significantly propelled by optimizing the performance of transition-metal-based electrodes. In this study, we introduce an innovative, in situ tellurization strategy to synthesize novel, flower-like hierarchical structures of nickel ditelluride/cobalt ditelluride (NiTe2/CoTe2) on a nickel foam substrate (labeled as NF/FNCT), making them promising candidates for electrodes in hybrid supercapacitors. Initially, we utilized a hydrothermal method to create flower-like NiCo-layered double hydroxide (NiCo-LDH) nanoarrays on nickel foam (NF/FNCLDH). This process was followed by the tellurization of these nanoarrays, which yields the NiTe₂/CoTe₂ nanostructures. The strategic assembly of active materials on a conductive substrate effectively obviates the need for inert, slow-conductive binders, thereby facilitating redox chemistry. Capitalizing on the synergistic effects of the conductive tellurium and hierarchical flower-like nanomorphology, the NF/FNCT showcases expedited electron/ion transport, enhanced efficiency, and exceptional electrochemical performance. The NF/FNCT electrode discloses an impressive capacity of 1388.9 (±3) C/g, superior rate capability (83.45 % capacity retention at 30 A/g), and remarkable cycling durability of 96.67 %. Furthermore, when integrated with activated carbon (AC), the resultant hybrid supercapacitor delivers a desirable energy density of 58.85 Wh kg−1 at a power density of 806.85 W kg−1, demonstrating commendable rate capability and cycling durability. This investigation opens new avenues for the synthesis of materials for hybrid supercapacitors.