聚阴离子型二次离子电池正极材料研究进展

Recent development of polyanionic cathodes for second ion batteries

二次离子电池作为诸多储能方式中的一种,具有循环性好、服役寿命长、安全性高、使用方便等优点,已广泛应用于便携式电子设备、电动汽车等领域。然而,随着锂、钴等资源的短缺以及可再生清洁能源的快速发展,亟需发展高效、低成本且环保的新型二次离子电池技术,但其发展受限于缺乏优异的正极材料。相比于其他二次离子电池正极材料,聚阴离子化合物具有种类丰富、结构多样、工作电压可调、循环稳定性好等优点,是发展低成本环保二次离子电池的理想正极材料。本文根据聚阴离子的种类,将其相应正极材料系统分为磷酸盐类、硫酸盐类、其他单一聚阴离子类和混合聚阴离子类,并以LiFePO_(4)、Na_(3)V_(2)(PO_(4))_(3)、NaVPO_(4)F、Na2Fe2(SO_(4))_(3)、KFeSO_(4)F、Li_(2)FeSiO_(4)等化合物为代表详细介绍了各类正极材料的晶体结构、电化学性能及储能机理。重点综述了各类聚阴离子型正极材料的研究进展,简要概述了对材料进行包覆、掺杂、纳米化等改性措施取得的研究成果。最后对聚阴离子型正极材料发展过程中的瓶颈(电子电导率低的问题)进行了论述,并提出了相应的解决策略。

Among various energy storage devices,rechargeable ion batteries(RIBs)have been commercialized in portable electronic devices,electric vehicles,etc.,thanks to their advantages of excellent reversibility,long lifespan,high safety and easy-to-operate property.With the shortage of lithium and cobalt resources and the promotion of renewable energy sources,high efficient RIBs with low-cost and environmental friendly merit are urgently required,whereas their developments are limited by the lack of suitable cathode materials.Compared with other candidates,polyanionic compounds have shown virtues of diversity,structural fruitfulness,adjustable working potential and great stability,and therefore are promising cathode materials for promoting the application of next-generation RIBs.In this paper,polyanion cathode materials are systematically classified into phosphate,sulfate,single polyanion and mixed polyanion,and the crystal structure and electrochemical properties of various cathode materials are introduced in detail with LiFePO_(4),Na_(3)V_(2)(PO_(4))_(3),NaVPO_(4)F,Na_(2)Fe_(2)(SO_(4))_(3),Li_(2)FeSiO_(4),etc.as the representative compounds.The research progress of various kinds of polyanionic cathode materials is reviewed,and the research achievements of coating,doping and nanocrystallization of the materials are briefly summarized.Finally,the bottleneck in the development of polyanionic cathode materials,i.e.,low electronic conductivity,is discussed,and the corresponding solutions are proposed.