可充电电池中具有空心结构的正极材料

Hollow structured cathode materials for rechargeable batteries

随着可充电电池应用的广泛应用,人们对可充电电池的性能(质量比容量、倍率性能和循环稳定性)提出了更高的要求.设计合成具有微纳米结构的电极材料是提升可充电电池电学性能的一个重要研究方向,其中空心结构设计因其有效性引起研究人员的重视.目前空心结构的应用主要集中在负极材料上,相比之下具有空心结构的正极材料因其较难的形貌控制以及较低的体积比容量,研究相对较少.本文总结了具有空心结构的正极材料在可充电电池,主要是在锂离子电池和钠离子电池中的应用,分析讨论了此类正极材料研究中取得的成绩以及存在的问题和挑战.由于空心结构具有更多的反应位点、利于电解液的渗透以及能缓解充放电过程中的体积变化,空心结构化能明显改进下一代高比容量正极材料(比如富锂层型材料、钒基氧化物、硅酸盐等)的电学性能.这些材料往往表现出较低的电子电导率、离子扩散系数和较高的体积变化率.我们相信通过精确控制空心结构的空间结构、开发低成本可放大的合成策略,空心结构能为未来的高性能正极材料提供较为实用化的解决方案.

Hollow structuring has been intensively studied as an effective strategy to improve the electrochemical performance of the electrode materials for rechargeable batteries in terms of specific capacity, rate capability, and cycling performance. To date, hollow structured anode materials have been extensively investigated, while hollow structured cathode materials(HSCMs) are relatively less explored because of the difficulties in morphological control as well as the concern of reduced volumetric capacities. In this paper, we provide an overview of the research advances in the synthesis and evolution of HSCMs for metal(Li, Na, etc.) ion batteries. Attributing to the advantages of hollow structures including high surface area, excellent accessibility to active sites, and enhanced mass transport and diffusion, hollow structuring can significantly improve the performance of high-capacity cathode materials with low kinetics, such as lithium rich layered oxides, silicates, and V2O5. It is anticipated that the precise and facile control of the spatial configuration can balance the electrochemical performance of HSCMs and the volumetric capacities of HSCMs, leading to practical high-performance batteries.