Gao Chao, Liu Haiping, Bi Sifu, Wang Yingnan, Wang Qiaoe, Fan Shanshan, Meng Xiaohuan
School of Marine Science and Technology, Harbin Institute of Technology, Weihai 264209, China.
School of Materials Science and Engineering, Harbin Institute of Technology, Weihai 264209, China.
ACS Appl Mater Interfaces. 2021 May 5;13(17):20014-20023. doi: 10.1021/acsami.1c01283. Epub 2021 Apr 14.
The solid-state method is extensively applied to the synthesis of electrode materials for its simplicity and low cost. However, particles obtained using the traditional solid-state method exhibited a large, uneven particle size and a severe aggregation phenomenon, leading to an unsatisfactory electrochemical performance. Here, spinel LiNiMnO (LNMO) with good dispersion was synthesized using the solid-state method with the addition of ,-dimethylpyrrolidone (NMP). During the LNMO preparation process, NMP is effective in refining and optimizing the particle size and suppressing the aggregation phenomenon. Meanwhile, the N element migration phenomenon was also observed in the bulk of LNMO, and it was beneficial for extending solid-solute reactions as demonstrated by in situ X-ray diffraction. LNMO prepared with NMP (LNMO-N-) exhibited a higher discharge voltage and capacity (115.3 mA h g at 2 C) compared with LNMO (105.8 mA h g). These results reveal the function of NMP in the preparation of LNMO and the effect of the physical characteristic changes on structure and phase transition in a working battery, and it can be easily incorporated into other electrode materials; if well engineered, it will contribute a lot to the further applications of lithium ion batteries.
固态法因其简单性和低成本而被广泛应用于电极材料的合成。然而，使用传统固态法获得的颗粒呈现出大的、不均匀的粒径以及严重的团聚现象，导致电化学性能不尽人意。在此，通过添加N-甲基吡咯烷酮（NMP）采用固态法合成了具有良好分散性的尖晶石LiNiMnO（LNMO）。在LNMO制备过程中，NMP在细化和优化粒径以及抑制团聚现象方面是有效的。同时，在LNMO本体中也观察到了N元素迁移现象，并且如原位X射线衍射所表明的，这有利于延长固溶体反应。与LNMO（105.8 mA h g）相比，用NMP制备的LNMO（LNMO-N-）表现出更高的放电电压和容量（在2 C时为115.3 mA h g）。这些结果揭示了NMP在LNMO制备中的作用以及物理特性变化对工作电池中结构和相变的影响，并且它可以很容易地应用于其他电极材料；如果设计得当，它将对锂离子电池的进一步应用有很大贡献。
