Gupta Disha, Muthiah Aravind, Do Minh Phuong, Sankar Gopinathan, Hyde Timothy I, Copley Mark Patrick, Baikie Tom, Du Yonghua, Xi Shibo, Srinivasan Madhavi, Dong ZhiLi
School of Materials Science and Engineering, Nanyang Technological University, 639798 Singapore.
Energy Research Institute@NTU (ERI@N) Nanyang Technological University Research Techno Plaza, 50 Nanyang Drive, 637553 Singapore.
ACS Omega. 2019 Jul 1;4(7):11338-11345. doi: 10.1021/acsomega.9b00356. eCollection 2019 Jul 31.
Here, we report the use of LiMn(SO) as a potential energy storage material and describe its route of synthesis and structural characterization over one electrochemical cycle. LiMn(SO) is synthesized by ball milling of MnSO·HO and LiSO·HO and characterized using a suite of techniques, in particular, ex situ X-ray diffraction, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy on the Mn and S K-edges to investigate the electronic and local geometry around the absorbing atoms. The prepared LiMn(SO) electrodes undergo electrochemical cycles to different potential points on the charge-discharge curve and are then extracted from the cells at these points for ex situ structural analysis. Analysis of X-ray absorption spectroscopy (both near and fine structure part of the data) data suggests that there are minimal changes to the oxidation state of Mn and S ions during charge-discharge cycles. However, X-ray photoelectron spectroscopy analysis suggests that there are changes in the oxidation state of Mn, which appears to be different from the conclusion drawn from X-ray absorption spectroscopy. This difference in results during cycling can thus be attributed to electrochemical reactions being dominant at the surface of the LiMn(SO) particles rather than in the bulk.
在此,我们报道了LiMn(SO)作为一种潜在储能材料的应用,并描述了其在一个电化学循环中的合成路线和结构表征。LiMn(SO)通过对MnSO·HO和LiSO·HO进行球磨合成,并使用一系列技术进行表征,特别是利用非原位X射线衍射、X射线光电子能谱以及Mn和S K边的X射线吸收光谱来研究吸收原子周围的电子结构和局部几何结构。制备的LiMn(SO)电极在充放电曲线上的不同电位点进行电化学循环,然后在这些点从电池中取出进行非原位结构分析。X射线吸收光谱(包括数据的近边和精细结构部分)分析表明,在充放电循环过程中,Mn和S离子的氧化态变化极小。然而,X射线光电子能谱分析表明Mn的氧化态存在变化,这似乎与X射线吸收光谱得出的结论不同。因此,循环过程中结果的这种差异可归因于LiMn(SO)颗粒表面而非整体中的电化学反应占主导。