In-situ growth and DFT analysis of nickel halide nanostructures for enhanced electrochemical supercapacitors

Abstract

Electrochemical supercapacitors with battery-like performance are pivotal for addressing the automobile industry's increasing energy demands, offering rapid charge/discharge capabilities, high power density, and excellent cycling stability. Nickel-based electrodes emerge as a promising solution due to their high capacity and cost-effectiveness compared to noble metals. Herein, nickel halide nanostructures (NiF2, NiBr2, NiI2) were synthesized via a hydrothermal method, with nickel foam serving as both the substrate and Ni+ source, enabling binder-free, self-growing electrodes. The synthesis process, supported by density functional theory (DFT) calculations, utilized different halide sources (NH4F, NH4Br, NH4I) to tailor performance. Among these, NiBr2 electrodes, characterized by interlinked nanowire structures, exhibited the highest specific capacity of 421.11 mAh g- 1 (equivalent to 2526.7 F g- 1 ) at 5 A g- 1 , with 93.3 % capacity retention after 1500 cycles. This study highlights the superior performance of NiBr2 electrodes, underscoring their potential for advanced super- capacitor applications.