Beka Lemu Girma, Li Xin, Wang Xiaoli, Han Chuanyu, Liu Weihua
School of Microelectronics, School of Electronic and Information Engineering, Xi'an Jiaotong University Xi'an 710049 P. R. China
RSC Adv. 2019 Oct 10;9(55):32338-32347. doi: 10.1039/c9ra05840k. eCollection 2019 Oct 7.
Transition metal sulphides are becoming one of the promising materials for energy storage applications. Particularly, an advanced electrode material architecture, which gives favourable electronic and ionic conductivity, is highly in demand. Herein, a hierarchical NiCoS honeycomb/NiCoS nanosheet core-shell structure is reported for supercapacitor applications. The core-shell structure was grown on a nickel foam two consecutive hydrothermal processes, followed by an electrochemical deposition process. Moreover, we tuned the deposition cycle to get abundant active sites with gaps of suitable sizes between the walls of the honeycomb structure for efficient electrolyte diffusion routes. The 3D honeycomb core structure was used as superhighway for electron transport to the current collector, while the ultrathin shell structure offered a large surface area with short electron and ion diffusion paths, thus leading to the faster kinetics and higher utilization of active materials. Thus, using the synergistic advantages of the core material and the shell material, the as-synthesized optimized electrode material came up with an excellent specific capacitance of 17.56 F cm at a current density of 5 mA cm and the highest cycling stability of 88.2% after 5000 cycles of charge-discharge process. Such advanced electrode architectures are highly promising for the future electrode materials.
过渡金属硫化物正成为储能应用中颇具前景的材料之一。特别是，一种能提供良好电子和离子导电性的先进电极材料结构备受需求。在此，报道了一种用于超级电容器应用的分级NiCoS蜂窝/NiCoS纳米片核壳结构。该核壳结构通过连续两次水热过程在泡沫镍上生长，随后进行电化学沉积过程。此外，我们调整沉积循环以获得丰富的活性位点，在蜂窝结构壁之间具有合适尺寸的间隙，以形成高效的电解质扩散路径。三维蜂窝状核心结构用作电子传输到集流体的超级高速公路，而超薄壳结构提供了大表面积以及短的电子和离子扩散路径，从而导致更快的动力学和更高的活性材料利用率。因此，利用核心材料和壳材料的协同优势，合成的优化电极材料在电流密度为5 mA cm时具有17.56 F cm的优异比电容，并且在5000次充放电循环后具有88.2%的最高循环稳定性。这种先进的电极结构对于未来的电极材料极具前景。
