Dear Enyuan,
as Wojciech said, you have certainly the effect of stacking faults. LiOH is a tetragonal structure and the layers are parallel with ab plane. It means that the faulting has an effect on the reflections with l-index non-zero. The faulting can be roughly understood as a size effect in the direction of c-axis. From your WH plot it is evident that the reflections 110 and 200 are not-affected while all the others with l non-zero are affected. With increasing l-index, the effect is stronger. You can easily refine this anisotropy with many Rietveld programs. Maybe somebody can provide a script for Topas for example or in Profex or Fullprof such models may be available. It stays to explain why the cycling of a battery introduce stacking faults in LiOH. Best regards Radovan Radovan Cerny Laboratoire de Cristallographie Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch<mailto:radovan.ce...@unige.ch> URL : http://www.unige.ch/sciences/crystal/cerny/rcerny.htm ________________________________ De : rietveld_l-requ...@ill.fr <rietveld_l-requ...@ill.fr> de la part de wslawin...@chem.uw.edu.pl <wslawin...@chem.uw.edu.pl> Envoyé : mercredi, 20 juillet 2022 11:16 À : rietveld_l-requ...@ill.fr Objet : Re: understanding peak width broadening during LiOH growth Dear Enyuan, LiOH is definitely a layered structure. In such kind of structures, it is likely that extra anisotropic broadening can be caused by “stacking faults”. In your case, peaks with mixed kh and l index are generally broader than those 00l or hk0. It would require a detailed study but you can also look at my paper https://pubs.acs.org/doi/full/10.1021/acs.inorgchem.6b02247 With best regards, Wojciech Slawinski wslawin...@chem.uw.edu.pl From: rietveld_l-requ...@ill.fr <> On Behalf Of Enyuan Hu Sent: Wednesday, July 20, 2022 5:41 AM To: RIETVELD_L Distribution List <rietveld_l@ill.fr> Subject: understanding peak width broadening during LiOH growth Hi all, I am seeking help on understanding why peak broadens during LiOH crystal development. Background: we have identified LiOH as a major component in the interphase of batteries and we are trying to understand how it evolves. We obtained the Williamson-Hall plot for the LiOH phase as shown below. Black: 1st cycle; Red: 5th cycle; Green: 30th cycle. So the green one has obvious anisotropic broadening and we found literature that suggests this is due to pallet-shaped LiOH. But going from 1st cycle to 30th cycle (black to green), the peak width is in general more broadened. We thought LiOH would grow in size so the peaks should become more sharp. So this is sort of against our expectations. Can such a phenomenon be explained by strain and if so, can anyone provide comments or suggestions? Thank you! Regards Enyuan [image.png]
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