Electrochemical properties and mechanism of CoMoO@NiWO core-shell nanoplates for high-performance supercapacitor electrode application studied X-ray absorption spectroscopy

• Published in: Nanoscale Vol. 12; no. 25; pp. 13388 - 13397
• Main Authors: Hsu, Feng Hao, Hsu, Su Yang, Pao, Chih Wen, Chen, Jeng Lung, Chen, Chi Liang, Chen, Jin Ming, Lu, Kueih Tzu
• Format: Journal Article
• Language: English
• Published: 02.07.2020
• DOI: 10.1039/d0nr00349b
• ISSN: 2040-3364

Binary transition metal oxide CoMoO 4 @NiWO 4 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 cm 2 ) 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 CoMoO 4 @NiWO 4 compared to that of CoMoO 4 nanoplates is attributed to a large electrochemical surface area and synergistic effect between NiWO 4 and CoMoO 4 . This combination of two binary transition metal oxides can hence provide an excellent route to develop a high-performance electrode material for supercapacitor applications. Binary metal oxide CoMoO 4 @NiWO 4 core-shell nanoplates possess the great electrochemical properties by synergistic effect between the two components. In-situ XAS indicates that the Co and Ni elements are simultaneously participated Faraday reaction.