Facile synthesis of hierarchical ZnS@FeSe2 nanostructures as new energy-efficient cathode material for advanced asymmetric supercapacitors
Syed Awais Ahmad, Muhammad Zia Ullah Shah, Shams Rahman, Muhammad Jalal Arif, Jiansheng Lu, Taihong Huang, Awais Ahmad, Abdullah A. Al‐Kahtani, Ammar M. Tighezza, Muhammad Sajjad, A. F. M. Shahen Shah, Peng Song, Muhammad Sufyan Javed
Abstract
We have effectively synthesized ZnS, FeSe2, and their nanocomposite using a straightforward and affordable solvothermal process. We also investigated for the first time their ideal electrochemical performance for supercapacitors. The ZnS and FeSe2 positive electrodes exhibit capacitances of 266.2 F g−1 and 294.3 F g−1, respectively, with fascinating nanostructures and morphology. Their respective nanocomposites, AZ-1, AZ-2, and AZ-3, deliver capacitances of 356.8, 444.4, and 326.1 F g−1 with significant rate performance in aqueous solution in a three-electrode assembly. The lowest ESR and Rct values of AZ-2 electrodes, which improved conductivity and charge transport kinetics and created a synergistic effect between ZnS and FeSe2 electrodes, are responsible for their exceptional capacitative performance. We built an asymmetric supercapacitor (AZ-2/AC) with an optimal voltage of 1.6 V, which demonstrated great power density (6250 W kg−1) and energy density (33 Wh kg−1) with remarkable cycling stability (88.1%) in an aqueous electrolyte after 12,000 cycles. As a result, FeSe2-based nanocomposites are strong contenders for realizing high energy and power delivery for practical applications.