物理化学学报 >> 2016, Vol. 32 >> Issue (6): 1489-1494.doi: 10.3866/PKU.WHXB2016032802

论文 上一篇    下一篇

P2型钠离子电池正极材料Na0.66Mn0.675Ni0.1625Co0.1625O2的表面重构及其演变的电子显微表征

黄威,邬春阳,曾跃武,金传洪*(),张泽   

  • 收稿日期:2016-03-17 发布日期:2016-06-03
  • 通讯作者: 金传洪 E-mail:chhjin@zju.edu.cn
  • 基金资助:
    国家自然科学基金(51222202)

Electron Microscopy Study of Surface Reconstruction and Its Evolution in P2-Type Na0.66Mn0.675Ni0.1625Co0.1625O2 for Sodium-Ion Batteries

Wei HUANG,Chun-Yang WU,Yue-Wu ZENG,Chuan-Hong JIN*(),Ze ZHANG   

  • Received:2016-03-17 Published:2016-06-03
  • Contact: Chuan-Hong JIN E-mail:chhjin@zju.edu.cn
  • Supported by:
    The project was supported by the National Natural Science Foundation of China(51222202)

摘要:

采用球差校正扫描透射电子显微镜(STEM)、X射线能谱(EDS)等分析手段表征了高温固相法合成的Na0.66Mn0.675Ni0.1625Co0.1625O2钠离子过渡金属氧化物正极材料。X射线衍射(XRD)结果表明该材料为结晶性良好的P2型钠离子层状氧化物(P63/mmc)。原子尺度的结构与成分分析显示材料表面存在宽度约为1-2 nm的表面重构层,重构区域内存在大量晶格畸变与反位缺陷,并伴有一定程度的成分偏析——表面富钴(Co)、缺镍(Ni)。进一步研究表明这些表面重构区域在时效过程中会发生明显的“退化”,即初始表面重构层宽度会进一步扩展至5-10 nm,部分区域钠离子耗尽,由层状结构转变为尖晶石(Spinel,Fd3m)与岩盐相(rocksalt,Fm3m)共存的结构。

关键词: 钠离子电池, P2型层状正极材料, 表面重构, 扫描透射电子显微镜

Abstract:

We performed an aberration-corrected scanning transmission electron microscopy(STEM)andenergy-dispersive X-ray spectroscopy(EDS)study of Na0.66Mn0.675Ni0.1625Co0.1625O2,which was prepared via a solidstatereaction for sodium-ion battery applications.Powder X-ray diffraction(XRD)showed that the material hada well-crystallized P2-type layered structure(P63/mmc).Results from further STEM and EDS analyses showedthe presence of reconstructed surface layers of thickness about 1-2 nm,which contained a large amount ofantisite defects and obvious lattice distortions.Detailed chemical analysis showed an inhomogeneous elementaldistribution inside these reconstructed surface layers;they were cobalt rich and nickel deficient.These surfacelayers further evolved into thicker regions of width 5-10 nm,accompanied by a spinel(Fd3m)phase to rocksaltphase(Fm3m)transition.

Key words: Sodium ion battery, P2-type layer-structured cathode material, Surface reconstruction, Scanning transmission electron microscopy

MSC2000: 

  • O646