Composites of NiCo Layered Double Hydroxide Nanosheets and Co₃S₄ Nanoparticles for Asymmetric Supercapacitors

Abstract

Transition metal layered double hydroxides (LDHs) with high theoretical specific capacity and abundant redox active centers are considered as ideal cathode materials for asymmetric supercapacitors, but limited specific surface area (SSA) and low conductivity hinder its electrochemical performance. Herein, layered NiCo-LDH nanosheets were synthesized by simple one-step ion exchange and co-precipitation method at room temperature using Co-ZIF-L as the metal precursor. Subsequently, Co3S4 nanoparticles were grown on NiCo-LDH nanosheets by controlling the amount of sulfur addition, thus constructing NiCo-LDH/Co3S4 composites with heterogeneous structures. The large SSA provided more active centers for the pseudocapacitance reaction, resulting in NiCo-LDH/Co3S4 obtaining high specific capacity and good rate capability (728.1 C g–1 at 1 A g–1 and 452.9 C g–1 at 20 A g–1). In addition, the assembled asymmetric supercapacitor (NiCo-LDH/S-100//AC) achieved a superior energy density (35.21 Wh g–1 at 749.98 W kg–1), showing considerable potential for practical applications.

Ultrafast Microwave-Assisted Synthesis of Porous NiCo Layered Double Hydroxide Nanospheres for High-Performance Supercapacitors

“…Molecules 2024, 29, x FOR PEER REVIEW 6 of 14 related to M-OH and -OH bonds at 531.1 eV and 532.3 eV [20]. This result is consistent with the infrared spectra, indicating the successful preparation of NiCo-LDH.…”

“…The C 1s spectrum of NiCo-LDH clearly shows three peaks of ethylene glycol, which are located at 284.4 eV (C-C/C-H), 286.1 eV (C-OH), and 288.3 eV (C-O) [ 39 ]. The spectrum of O 1s can be clearly seen, and the binding energy for O 1 s was related to M-OH and -OH bonds at 531.1 eV and 532.3 eV [ 20 ]. This result is consistent with the infrared spectra, indicating the successful preparation of NiCo-LDH.…”

“…Nevertheless, despite all of the potential benefits, there are still certain obstacles that need to be resolved in practical applications with NiCo-LDH electrode materials. For example, the synthesis method, structural regulation, and performance optimization of NiCo-LDH still need further study and improvement [ 20 , 21 , 22 , 23 ]. Therefore, numerous studies have been conducted in an effort to enhance its electrochemical properties.…”