高性能スーパーキャパシタ向けトリメタル硫化物の電気化学的性能向上を目的とした金属酸化物ナノコンポジットエンジニアリング

Supercapacitors, considered a potential energy storage device, can address the long-awaited problem of the energy crisis by storing energy for efficient, rapid, and sustainable utilization across diverse applications, from portable electronics to large-scale power systems. Herein, we have prepared a novel nanocomposite material via a novel ultrasonication-assisted solvothermal approach, combining the Fe_0.67Cu_0.22Co_0.11S nanoparticles and CuO in different weight ratios. X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy analyses confirmed the successful synthesis of the targeted nanocomposites. Electrochemical evaluation revealed that the FeCuCoS/CuO 5 : 1 composition (denoted as U5), identified as optimal material, exhibited a remarkable specific capacitance of 1407 F g^-1 at 0.7 A g^-1, corresponding to enhancements of 3.9-fold and 120-fold compared to pristine Fe_0.67Cu_0.22Co_0.11S and CuO, respectively. Furthermore, the asymmetric supercapacitor device based on U5 demonstrated superior electrochemical performance, delivering a specific capacity of 311 C g^-1 at 0.5 A g^-1, an energy density of 70 Wh kg^-1, a power density of 4800 W kg^-1, a coulombic efficiency of 97.1%, and a long-term cycling stability of 92.86% after 3000 cycles. Dunn's model analysis indicated that charge storage was predominantly capacitive (51.3% at 10 mV s^-1), while power-law fitting yielded b-values of 0.71-0.80, indicating hybrid supercapacitor behavior. Overall, Fe_0.67Cu_0.22Co_0.11S/CuO nanocomposites demonstrated durable, high-performance characteristics for advanced energy storage applications.