多孔钒基锂离子电池电极材料的可控制备及性能

Rechargeable lithium ion batteries with merits, such as high energy and power densities, and long cycle lifetime, have been regarded as ideal energy storage devices for electric, hybrid electric vehicles, and intermittent renewable energy sources. One of the challenges for improving the performance of lithium ion batteries to meet increasingly demanding requirements for energy storage is the development of low-cost, high performance cathode materials. Due to high capacity, high output voltage, readily availability and low cost, vanadium-based cathode materials has been attracted considerable attention. However, the poor rate capability and cycleability restrict the practical application of vanadium-based cathode materials. This project will focus on the design and fabrication of new porous vanadium-based cathode materials, such as vanadium oxides and vanadates. New preparation strategies, including soft-template and hard-template methods will be developed to manipulate the porous structures and pore dimensions of these materials. The phase, crystallinity and stability of the porous vanadium-based materials will be well controlled through careful selection of the synthesis and post-treatment processes. The introduction of a porous structure is expected to facilitate the transport of the electrolyte and shorten the diffusion distance of lithium ions and electrons. The doping and surface coating are feasible to enhance the lithium ion and electron conductivities of the cathode materials. As a result, the rate capability and cycleability of these materials will be improved. In situ characterization techniques, such as in situ X-ray diffraction, will be employed to investigate the processes of lithium ion intercalation/de-intercalation to elucidate the key factors that impact the performance of the cathode materials. This research will shed some new light on the preparation and properties of porous cathode materials for high-performance lithium ion batteries.

锂离子电池和锂离子电池储能系统的开发对可再生能源的有效利用和新能源汽车的发展具有重要意义，而正极材料一直是制约锂离子电池发展的瓶颈。本项目拟以比容量高、廉价的钒基材料为突破口，设计合成出新型钒氧化合物和钒酸锂等多孔正极材料。开发软模板法和硬模板法等新的制备路线，优化制备和后处理条件，控制多孔骨架材料的晶相，提高其结晶度以及热稳定性，实现材料的可控制备；通过多孔结构的引入促进电解液的输运，加快材料内部的传质过程，通过离子掺杂和表面包覆等复合改性解决材料锂离子迁移率过低和导电性差的难题；利用原位X-射线衍射等在线检测手段研究材料的储锂机理，以期从本质上揭示影响锂离子电池性能的关键因素，为开发具有自主知识产权的、低成本、大容量、高倍率和高循环稳定性的锂离子电池电极材料进行积极探索。

锂离子电池和锂离子电池储能系统的开发对可再生能源的有效利用和新能源汽车的发展具有重要意义，而正极材料一直是制约锂离子电池发展的瓶颈。本项目以比容量高、廉价的钒基材料为突破口，设计合成了新型钒氧化合物和钒酸锂等多孔正极材料，并对制备和后处理条件进行了优化。通过开发新的制备路线和软模板法和硬模板法制备途径，控制多孔骨架材料组成和晶相，获得了一系列性能优异的锂离子电池、锂空气电池和超级电容器电极材料；多孔结构的引入推动电解液的输运，加快材料内部的传质过程，掺杂和表面包覆等复合改性解决材料锂离子迁移率过低和导电性差的难题。利用原位X-射线衍射等在线检测手段研究了多孔钒基和钼基电极材料的脱嵌锂离子的过程，揭示了其储锂机理。对开发具有自主知识产权的、低成本、大容量、高倍率和高循环稳定性的锂离子电池电极材料进行了积极探索。在Adv. Mater., Nano Lett. Adv. Funct. Mater.等国际知名学术期刊上共发表SCI收录论文20余篇，影响因子大于10的有6篇，申请了4项国家发明专利。