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• 作者：Yubo Shao ; Yongqing Zhao ; Hua Li ; Cailing Xu
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：December 28, 2016
• 年：2016
• 卷：8
• 期：51
• 页码：35368-35376
• 全文大小：654K
• ISSN：1944-8252

文摘

Active materials and special structures of the electrode have decisive influence on the electrochemical properties of supercapacitors. Herein, three-dimensional (3D) hierarchical Ni_xCo_1–xO/Ni_yCo_2–yP@C (denoted as NiCoOP@C) hybrids have been successfully prepared by a phosphorization treatment of hierarchical Ni_xCo_1–xO@C grown on nickel foam. The resulting NiCoOP@C hybrids exhibit an outstanding specific capacitance and cycle performance because they couple the merits of the superior cycling stability of Ni_xCo_1–xO, the high specific capacitance of Ni_yCo_2–yP, the mechanical stability of carbon layer, and the 3D hierarchical structure. The specific capacitance of 2638 F g^–1 can be obtained at the current density of 1 A g^–1, and even at the current density of 20 A g^–1, the NiCoOP@C electrode still possesses a specific capacitance of 1144 F g^–1. After 3000 cycles at 10 A g^–1, 84% of the initial specific capacitance is still remained. In addition, an asymmetric ultracapacitor (ASC) is assembled through using NiCoOP@C hybrids as anode and activated carbon as cathode. The as-prepared ASC obtains a maximum energy density of 39.4 Wh kg^–1 at a power density of 394 W kg^–1 and still holds 21 Wh kg^–1 at 7500 W kg^–1.