Free-Standing T-Nb2O5/Graphene Composite Papers with Ultrahigh Gravimetric/Volumetric Capacitance for Li-Ion Intercalation Pseudocapacitor

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• 作者：Lingping Kong ; Chuanfang Zhang ; Jitong Wang ; Wenming Qiao ; Licheng Ling ; Donghui Long
• 刊名：ACS Nano
• 出版年：2015
• 出版时间：November 24, 2015
• 年：2015
• 卷：9
• 期：11
• 页码：11200-11208
• 全文大小：748K
• ISSN：1936-086X

文摘

Free-standing electrodes with high gravimetric/volumetric capacitance will open up potential applications in miniaturized consumer electronics. Herein, we report a simple synthesis technology of free-standing orthorhombic Nb₂O₅ (T-Nb₂O₅)/graphene composite papers for Li-intercalating pseudocapacitive electrodes. Through a facile polyol-mediated solvothermal reaction, the Nb₂O₅ nanodots are homogeneously decorated onto the surface of reduced graphite oxide (rGO), which can form a homogeneous Nb₂O₅/rGO colloidal suspension that can be easily fabricated into flexible composite papers. The heat-treated T-Nb₂O₅/graphene composite papers exhibit a nanoporous layer-stacked structure with good ionic鈥揺lectric conductive pathways, high T-Nb₂O₅ loading of 74.2%, and high bulk density of 1.55 g cm^鈥?. Such T-Nb₂O₅/graphene composite papers show a superior pseudocapacitor performance as free-standing electrodes, as evidenced by an ultrahigh gravimetric/volumetric capacitance (620.5 F g^鈥? and 961.8 F cm^鈥? at 1 mV s^鈥?) and excellent rate capability. Furthermore, an organic electrolyte-based asymmetric supercapacitor is assembled based on T-Nb₂O₅/graphene composite papers, which can deliver a high energy density of 47 W h kg^鈥? and power density of 18 kW kg^鈥?.