多孔LiFePO4正极材料的研究进展

Research progress of porous lithium iron phosphate

摘要:

锂离子电池是高效、清洁的储能装置，在便携式电子产品、储能设施和电动汽车等领域具有广泛的应用前景，对于缓解能源危机和环境污染具有重要意义。橄榄石型LiFePO4是最有前途的锂离子电池正极材料之一。然而，相对低的本征电子电导率与锂离子扩散速率限制了LiFePO4倍率性能的发挥，阻碍其在动力锂离子电池领域的大规模商业化应用。纳米化是一种能有效改善LiFePO4倍率性能的方法，但纳米粒子存在表面能高，易团聚结块，性能衰减较快等问题。近些年的研究表明，三维多孔结构的LiFePO4兼具纳米与微米级活性材料的优点，是LiFePO4正极材料的研究热点和重要的发展方向。本文从合成方法、形貌结构、电化学性能以及结构－性能关系等方面系统总结多孔LiFePO4材料的研究进展，并展望其发展前景。

Abstract:

Lithium-ion batteries (LIBs) are efficient and clean energy storage devices, and are promising for various applications such as consumer electronic products, energy storage facilities and electric vehicles, etc, which are significant to relieve the energy crisis and environmental pollution. Olivine lithium iron phosphate (LiFePO4) is one of the most promising positive electrode material for LIBs. However, the intrinsically low electronic conductivity and lithium ion diffusion velocity result in poor performance of LiFePO4 and block its large-scale commercialization application for power LIBs. Nano-structured morphology control is believed to be an effective modification method to improve the rate performance of LiFePO4, nevertheless, LiFePO4 nanoparticles display some disadvantages such as high surface energy, easy to agglomeration and fast specific capacity degradation, etc. Studies in recent years demonstrate that the three dimensional porous LiFePO4 combines both advantages of nano- and micro-sized active materials, which is the research hotspot and important development direction of LiFePO4 materials. In this review, we systematically summarize the reseach progress of porous LiFePO4 materials from the aspects of synthesis methods, morphologies and structure, electrochemical performances, and the relationship between structure and performance, and outlook the future developments of porous LiFePO4 materials.