Unveiling the role of synthesis atmosphere in regulating phase transition and structural ordering of layered NCM622 cathodes
Unveiling the role of synthesis atmosphere in regulating phase transition and structural ordering of layered NCM622 cathodes
研究概述
比较空气与氧气气氛下NCM622正极的高温形成过程。XPS、XAFS及原位中子衍射表明氧气促进岩盐相向有序层状相转变，提高Ni平均价态及局域Ni—O有序度，减少缺陷。氧气煅烧样品循环100次后容量保持率92.23%–94.89%，倍率和离子扩散性能也得到改善。
谱图与表征信息
Fig. 2. Morphology, crystal structure, and local Ni coordination of NCM622 samples prepared under different calcination conditions. (a-d) SEM images of A-6h, A-12h, O-6h, and O-12h, respectively. (e-h) XRD Rietveld refinement plots of A-6h, A-12h, O-6h, and O-12h, respectively. (i, j) Ni K-edge XANES and Fouriertransformed EXAFS spectra. (k-n) WT-EXAFS maps of A-6h, A-12h, O-6h, and O-12h, respectively.