基于三维石墨烯构建高能量密度锂电池钒基正极材料体系及其电化学性能研究

Because of their high specific capacity, good cycling performance and charge retention capability, lithium-ion batteries (LIBs) have been widely used in portable electronic devices. To date, due to restriction of the material structure design, organization control and technological optimization, the performance of the commercial LIBs still cannot meet the requirement of high energy density and power capability for electric vehicles and renewable energy storage. In order to improving the comprehensive performance of LIBs, it is an important topic in this research field to seek the new cathode material system. Due to their high porosity, large internal surface area, and outstanding electrical and mechanical properties, three-dimensional graphene networks (3DG) have received extensive attention. Based on our technology innovation, we choose the high-capacity vanadium-based cathode materials and 3DG to create the high-energy-density, non-conductive-additive and non-binder three-dimensional cathode material system. Taking the advantages of 3DG, controllable preparation of nanostructure materials, pre-lithiation and cations doping, we hope to get a new generation of lithium battery cathode materials system with superior performance and promote the new development of lithium ion batteries.

锂离子电池因为其较高的容量、良好的循环性能及荷电保持能力被广泛地应用在便捷式的电子器件中。但由于受材料结构设计、组织控制、工艺优化等问题的制约，目前商业化锂离子电池还不能很好地满足电动车、可再生能源储能对高能量、大功率的诸多要求。为了提高电池的综合性能，寻求新的电极材料体系成为本领域研究的重要课题。三维石墨烯网络由于具有独特的多孔结构，有很大的比表面积、优异电子传导特性和优越的机械性能，而受到广泛关注。本课题通过采用自有创新技术为基础，选择高容量的钒基正极材料与微纳结构可控的三维石墨烯网络复合为研究突破口，实现基于三维石墨烯来构建高能量密度、无导电添加剂和粘结剂的三维锂电池正极材料体系。通过集合三维石墨烯、纳米结构的可控制备、嵌锂或阳离子掺杂等技术，来提高钒基材料体系的电化学性能，获得新一代性能优越的锂电池正极材料体系，推进新型锂离子电池研发进程。

当前锂离子电池在移动电子等小型设备中具有广泛的应用。然而，由于商业化正极材料的性能限制，特别是比容量过低，目前锂离子电池还不能很好地满足电动汽车和规模化储能系统的使用要求。因此，寻找和开发新的电极材料体系成为重要的研究课题。钒基金属氧化物材料具有资源丰富，价态多变，易于规模化合成等优势，在先进储能材料领域具有广阔的应用前景。同时，三维基底（石墨烯，碳布等）具有丰富的孔结构，高比表面积和优异的电子传导特性，受到广泛关注。本项目通过制备钒基金属氧化物与三维基底的复合材料，优化其复合结构，得到了具有较高容量的电极材料。考虑到该类材料在规模化储能领域的应用，我们也调研了其在钠离子电池和水系锌离子电池等新兴二次电池领域的应用价值，同样得到了理想的实验结果。证明了钒基金属氧化物和三维导电基底的复合材料在规模化储能领域具有较高的实际应用价值。