新型TiO2(B)基复合材料的微纳结构调控与储锂机制研究

To develop large-scale energy-storage technologies with high efficiency and low cost is crucial to the utilization of renewable energy, and is one of the most important parts in China's Energy Strategy for the Future. Electrochemical energy storage has become the important research direction in the fields of grid-scale energy storage because of high energy densities, short response time, low-cost maintenance, and flexibility. This project aims to develop highly revisable anode materials in lithium-ion batteries (LIBs) for next-generation grid-scale energy storage. Rational synthesis, nano/micro-assembly, and surface modification of TiO2(B) nanocrystals and TiO2-based nanocomposites will be carried out. The controllable growth and formation mechanism of TiO2-based nanocomposites will be explored. The dependence of the electrochemical properties on the composition, structure, morphology, and 3D architecture will be investigated systematically. The relationship between the microstructure/nanostructure and the lithium-storage performance together with the evolution rule will be clarified. Furthermore, we will explore the processes of the electron conduction and Li-ion diffusion during electrochemical discharge/charge reactions, facilitating the controlled synthesis as well as the future use of the resulting high-performance anode materials in LIBs. It is expected that this research would not only provide beneficial guidance and help to next-generation long-life, high-capacity LIBs for grid-scale energy storage, but also lay the scientific foundations for large-scale electrochemical energy storage, thus promoting the discipline cross and fusion of materials, chemistry, energy, etc.

研究与开发高效、廉价的大规模储能技术是利用可再生能源的关键，是国家未来能源战略的重要组成部分。电化学储能具有能量密度高、响应时间快、维护成本低、灵活方便等优点，成为目前大规模储能技术的重要发展方向。本项目旨在研发一系列面向下一代用于电网储能的长寿命锂离子电池负极材料，主要研究TiO2(B)纳米晶及其复合物的可控制备与微/纳组装、表面改性，探索TiO2(B)基复合材料可控生长与形成机制，系统研究TiO2(B)基纳米复合物的化学组成、晶体结构、形态、三维组装对其电化学性能的影响，揭示微/纳米结构与储锂性能的构效关系、演变规律以及电子传导、锂离子扩散相关原理，实现高性能锂离子电池负极材料的可控制备与应用。为开发下一代长寿命高比容量的电网储能用锂离子电池负极材料提供有益的指导与帮助，为规模化电化学储能技术的发展奠定科学基础，促进材料、化学、能源等学科的交叉融合。

本项目通过原位自组装、微波化学等创新的材料制备方法，设计合成与可控构筑了基于TiO2的纳米复合结构电极材料，系统研究了晶相结构、表面键合、纳米复合等关键因素对储锂/储钠电化学性能的影响。结合第一性原理理论计算，揭示了快速锂离子传输的插层赝电容机制，提出了“表面键合强偶联”有利于提升电荷传输能力与储锂容量。在本项目研究内容的基础上，进一步拓展了TiO2储锂材料的应用，探索了纳米复合TiO2电极材料在混合锂离子电容器中的应用基础，研究了TiO2电极的储钠性能，为发展高性能长寿命大规模储锂器件提供理论模型与实验基础，对推动TiO2电极材料在电池中的产业化应用具有重要的意义。由于Nb2O5的电化学特性与TiO2材料类似，我们进一步探索了Nb2O5纳米结构材料的储锂特性。标注该项目资助的SCI学术论文38篇，主要发表在Nat. Commun.、Chem. Soc. Rev.、Adv. Mater.、Adv. Energy Mater.、Small, J. Mater. Chem. A、Chem. Eur. J.、ACS Appl. Energy Mater.等著名国际学术期刊上，受到了国内外同行的广泛关注。发表在Nat. Commun.的论文入选了ESI高被引论文与热点论文，并且入选2015年度“中国百篇最具影响国际学术论文”及“2015年度华中科技大学十大科技进展”。