Asymmetric Supercapacitors Using 3D Nanoporous Carbon and Cobalt Oxide Electrodes Synthesized from a Single Metal鈥揙rganic Framework

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• 作者：Rahul R. Salunkhe ; Jing Tang ; Yuichiro Kamachi ; Teruyuki Nakato ; Jung Ho Kim ; Yusuke Yamauchi
• 刊名：ACS Nano
• 出版年：2015
• 出版时间：June 23, 2015
• 年：2015
• 卷：9
• 期：6
• 页码：6288-6296
• 全文大小：686K
• ISSN：1936-086X

文摘

Nanoporous carbon and nanoporous cobalt oxide (Co₃O₄) materials have been selectively prepared from a single metal鈥搊rganic framework (MOF) (zeolitic imidazolate framework, ZIF-67) by optimizing the annealing conditions. The resulting ZIF-derived carbon possesses highly graphitic walls and a high specific surface area of 350 m²路g^鈥?, while the resulting ZIF-derived nanoporous Co₃O₄ possesses a high specific surface area of 148 m²路g^鈥? with much less carbon content (1.7 at%). When nanoporous carbon and nanoporous Co₃O₄ were tested as electrode materials for supercapacitor application, they showed high capacitance values (272 and 504 F路g^鈥?, respectively, at a scan rate of 5 mV路s^鈥?). To further demonstrate the advantages of our ZIF-derived nanoporous materials, symmetric (SSCs) and asymmetric supercapacitors (ASCs) were also fabricated using nanoporous carbon and nanoporous Co₃O₄ electrodes. Improved capacitance performance was successfully realized for the ASC (Co₃O₄//carbon), better than those of the SSCs based on nanoporous carbon and nanoporous Co₃O₄ materials (i.e., carbon//carbon and Co₃O₄//Co₃O₄). The developed ASC with an optimal mass loading can be operated within a wide potential window of 0.0鈥?.6 V, which leads to a high specific energy of 36 W路h路kg^鈥?. More interestingly, this ASC also exhibits excellent rate capability (with the highest specific power of 8000 W路kg^鈥? at a specific energy of 15 W路h路kg^鈥?) combined with long-term stability up to 2000 cycles.