Hsu Feng Hao, Hsu Su Yang, Pao Chih Wen, Chen Jeng Lung, Chen Chi Liang, Chen Jin Ming, Lu Kueih Tzu
National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan.
Nanoscale. 2020 Jul 2;12(25):13388-13397. doi: 10.1039/d0nr00349b.
Binary transition metal oxide CoMoO4@NiWO4 core-shell nanoplates grown directly on a Ni foam substrate were synthesized via a facile two-step hydrothermal process. The core-shell nanoplates with high electrochemical surface area (2933 cm2) demonstrated excellent electrochemical properties (areal capacity as high as 0.464 mA h cm-2 at a current density of 5 mA cm-2) and great cycle stability (92.5% retention after 3000 cycles with a high current density of 40 mA cm-2). The mechanism of the electrochemical reactions based on the in situ X-ray absorption spectroscopy technique clearly shows that the Co and Ni elements simultaneously participate in the faradaic reactions with the electrolyte. These results indicate that the excellent electrochemical performance of CoMoO4@NiWO4 compared to that of CoMoO4 nanoplates is attributed to a large electrochemical surface area and synergistic effect between NiWO4 and CoMoO4. This combination of two binary transition metal oxides can hence provide an excellent route to develop a high-performance electrode material for supercapacitor applications.
通过简便的两步水热法合成了直接生长在泡沫镍基底上的二元过渡金属氧化物CoMoO4@NiWO4核壳纳米片。具有高电化学表面积（2933 cm2）的核壳纳米片表现出优异的电化学性能（在5 mA cm-2的电流密度下面积容量高达0.464 mA h cm-2）和良好的循环稳定性（在40 mA cm-2的高电流密度下3000次循环后保留率为92.5%）。基于原位X射线吸收光谱技术的电化学反应机理清楚地表明，Co和Ni元素同时参与与电解质的法拉第反应。这些结果表明，与CoMoO4纳米片相比，CoMoO4@NiWO4优异的电化学性能归因于大的电化学表面积以及NiWO4和CoMoO4之间的协同效应。因此，这两种二元过渡金属氧化物的组合可为开发用于超级电容器应用的高性能电极材料提供一条优异的途径。
