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Fig. (a) SEM cross-section of a three-dimensional graphene/vanadium pentoxide positive electrode material (Vertical illustration of Advanced Materials); (b) SEM photograph of three-dimensional graphene; (c) Charge-discharge cycle curve (5C, 2000 times)
Liu Jinhua, Research Associate of the Institute of Intelligent Machinery, Hefei Institute of Physical Science, Chinese Academy of Sciences, and Liu Jinyun, Associate Researcher of the Huang Xingji Group, have achieved new results in the development of high-performance graphene lithium-ion batteries, and developed three-dimensional graphene nanocomposite lithium ions with high capacity and long lifetime. Battery material. The research results were published in the international journal Adv. Mater. 2016, 28, 7696-7702, and were selected as the first paper.
From portable electronic devices to new energy electric vehicles, there is an urgent need for high-performance lithium-ion batteries. As the core of lithium ion batteries, electrode active materials are generally required to have high capacity and energy density, long-term cycle stability, and safety. In order to obtain high capacity and energy density, the proportion of active material in the electrode should be maximized; cycle stability and safety require that the battery material have excellent electron transport and ion diffusion properties. Three-dimensional nanostructures are ideal materials to meet the above requirements, but general three-dimensional battery materials contain metal or other high-density materials as frame supports, greatly reducing the proportion of active materials, reducing the capacity of the full battery, and also becoming long-term cycle stability. The limiting factor.
Liu Jinyun and others collaborated with the University of Illinois at Urbana-Champaign and Hefei Research Institute of the Chinese Academy of Sciences to develop a three-dimensional graphene-based composite battery material with a high active material loading, a short ion electron transport path, and an electrode material assembled into a battery. Need to use any binder and conductive agent and other additives, the battery has high capacity and excellent cycle stability. Developed three-dimensional graphene/vanadium pentoxide battery cathode material, after 12 minutes of full charge/discharge conditions, the battery capacity is greater than 200 mAh/g after 2000 cycles (many reports less than 1000 times, the capacity is generally lower than 150 mAh/ g); and the capacity of one minute of charging, to a commercial and literature-reported close capacity of more than 5 minutes. In addition, the three-dimensional graphene composite battery material structure design can also be applied to lithium ion battery anode materials, such as the development of graphene/silicon composite anode, exhibiting good versatility.
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