Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, P. R. China.
Center of Quantum Materials & Devices and College of Physics, Chongqing University, Chongqing 401331, P. R. China.
Dalton Trans. 2023 Jan 31;52(5):1345-1356. doi: 10.1039/d2dt03167a.
Transition metal sulfides have become more and more important in the field of energy storage due to their superior chemical and physical properties. Herein, dahlia β-NiS with a rough surface and β-NiS@reduced graphene oxide (rGO) have been green synthesized by a one-step hydrothermal method. The interface characteristics of β-NiS@ rGO composites have been systematically studied by XPS, Raman, and first-principles calculations. It is found that the residual O atoms in the interface and the polarization charge generated by them play an important role in performance enhancement. The NiS@rGO composite material has the best electrochemical performance when the C/O ratio is 6.48. Furthermore, we designed a NiS@rGO//rGO asymmetric supercapacitor with a potential window of 1.7 V. Its excellent energy density and power density demonstrate the advantages of the optimized NiS@rGO electrode. When the power density is 850 W kg, the energy density can reach 40.4 W h kg. Even at a power density of up to 6800 W kg, the energy density can be maintained at 17.6 W h kg. These encouraging results provide a possible pathway for designing asymmetric supercapacitors with ultra-high performance and a feasible strategy for the precise control of electrochemical performance.
过渡金属硫化物由于其优异的化学和物理性质，在储能领域变得越来越重要。在此，通过一步水热法绿色合成了具有粗糙表面的百合状 β-NiS 和 β-NiS@还原氧化石墨烯（rGO）。通过 XPS、拉曼和第一性原理计算系统地研究了β-NiS@rGO 复合材料的界面特性。结果发现，界面处的残留 O 原子及其产生的极化电荷对性能的提高起着重要作用。当 C/O 比为 6.48 时，NiS@rGO 复合材料具有最佳的电化学性能。此外，我们设计了一种具有 1.7 V 电势窗口的 NiS@rGO//rGO 非对称超级电容器。其优异的能量密度和功率密度显示了优化后的 NiS@rGO 电极的优势。当功率密度为 850 W kg 时，能量密度可达 40.4 W h kg。即使在高达 6800 W kg 的功率密度下，能量密度也可以保持在 17.6 W h kg。这些令人鼓舞的结果为设计具有超高性能的非对称超级电容器提供了一种可能的途径，也为精确控制电化学性能提供了一种可行的策略。
