Mesoporous Hybrids of Reduced Graphene Oxide and Vanadium Pentoxide for Enhanced Performance in Lithium-Ion Batteries and Electrochemical Capacitors

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• 作者：Gaind P. Pandey ; Tao Liu ; Emery Brown ; Yiqun Yang ; Yonghui Li ; Xiuzhi Susan Sun ; Yueping Fang ; Jun Li
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：April 13, 2016
• 年：2016
• 卷：8
• 期：14
• 页码：9200-9210
• 全文大小：730K
• 年卷期：0
• ISSN：1944-8252

文摘

Mesoporous hybrids of V₂O₅ nanoparticles anchored on reduced graphene oxide (rGO) have been synthesized by slow hydrolysis of vanadium oxytriisopropoxide using a two-step solvothermal method followed by vacuum annealing. The hybrid material possesses a hierarchical structure with 20–30 nm V₂O₅ nanoparticles uniformly grown on rGO nanosheets, leading to a high surface area with mesoscale porosity. Such hybrid materials present significantly improved electronic conductivity and fast electrolyte ion diffusion, which synergistically enhance the electrical energy storage performance. Symmetrical electrochemical capacitors with two rGO–V₂O₅ hybrid electrodes show excellent cycling stability, good rate capability, and a high specific capacitance up to ∼466 F g^–1 (regarding the total mass of V₂O₅) in a neutral aqueous electrolyte (1.0 M Na₂SO₄). When used as the cathode in lithium-ion batteries, the rGO–V₂O₅ hybrid demonstrates excellent cycling stability and power capability, able to deliver a specific capacity of 295, 220, and 132 mAh g^–1 (regarding the mass of V₂O₅) at a rate of C/9, 1C, and 10C, respectively. The value at C/9 rate matches the full theoretical capacity of V₂O₅ for reversible 2 Li⁺ insertion/extraction between 4.0 and 2.0 V (vs Li/Li⁺). It retains ∼83% of the discharge capacity after 150 cycles at 1C rate, with only 0.12% decrease per cycle. The enhanced performance in electrical energy storage reveals the effectiveness of rGO as the structure template and more conductive electron pathway in the hybrid material to overcome the intrinsic limits of single-phase V₂O₅ materials.