超级电容器
电容
材料科学
介孔材料
柯肯德尔效应
电解质
电极
化学工程
结晶度
电化学
双金属
阳极
储能
纳米技术
复合材料
化学
催化作用
冶金
物理
工程类
量子力学
物理化学
功率(物理)
生物化学
作者
Zohre Fahimi,Omran Moradlou,Amr Sabbah,Kuei‐Hsien Chen,Li‐Chyong Chen,Mohammad Qorbani
标识
DOI:10.1016/j.cej.2022.135225
摘要
Bimetal oxides are promising materials in the field of energy storage due to their various oxidation states, synergistic interactions among multiple metal species, and stability. In this work, Co3V2O8 hollow spheres are synthesized by a two-step hydrothermal method: (i) synthesis of V2O5 spheres and (ii) partial replacement of V by Co through the Kirkendall effect. As an electrode, it shows an extrinsic pseudocapacitive charge-storage mechanism due to different oxidation states of V and Co ions. Because of the low crystallinity degree of the mesoporous wall and high accessible surface area of hollow spheres, the optimum Co3V2O8 electrode reaches a high specific capacitance of 2376F g−1 at a current density of 2 A g−1, which is more than two times higher than the top reported values, and a rate capability retention of ∼80% at 20 A g−1. Using Co3V2O8, activated carbon, and KOH as positive, negative electrodes, and electrolyte, respectively, a hybrid supercapacitor device presents maximum energy and power densities of 59.2 Wh kg−1 and 36.6 kW kg−1, respectively. Further, the aqueous supercapacitor device shows superior structural and electrochemical stabilities after 10,000 galvanostatic charge–discharge cycles because of the arrays of voids in the orthorhombic crystal structure of Co3V2O8 that can decrease the volume expansion/shrinkage during the intercalation/deintercalation processes. Our results provide a platform for exploring bimetallic Co and V-based oxides, hydroxides, and sulfides nanostructures as promising energy storage materials in the future.
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