Publication: First principles study of small hole polaron formation in doped olivine LiFe<inf>1−x</inf>Co<inf>x</inf>PO<inf>4</inf>: Effects of Li deficiency
Issued Date
2021-03-01
Resource Type
ISSN
23524928
Other identifier(s)
2-s2.0-85100389126
Rights
Mahidol University
Rights Holder(s)
SCOPUS
Bibliographic Citation
Materials Today Communications. Vol.26, (2021)
Suggested Citation
Chanaprom Cholsuk, Sujin Suwanna, Kritsanu Tivakornsasithorn First principles study of small hole polaron formation in doped olivine LiFe<inf>1−x</inf>Co<inf>x</inf>PO<inf>4</inf>: Effects of Li deficiency. Materials Today Communications. Vol.26, (2021). doi:10.1016/j.mtcomm.2021.102043 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/76956
Research Projects
Organizational Units
Authors
Journal Issue
Thesis
Title
First principles study of small hole polaron formation in doped olivine LiFe<inf>1−x</inf>Co<inf>x</inf>PO<inf>4</inf>: Effects of Li deficiency
Other Contributor(s)
Abstract
Small hole polarons, charge carriers for electronic conductivity, play crucial roles in the performance of olivine LiMPO4 (M = Fe, Co, Mn, Ni) batteries, yet their formation mechanism and effects have not been completely explored. This work is aimed to apply density functional theory with additional on-site Hubbard corrections (DFT+U) to investigate the formation mechanism and the effects of small hole polarons in olivine LiFe1−xCoxPO4. It is found that small hole polarons always localize first at the Fe sites and then at the Co sites only when the Fe sites are fully occupied. The results show that much less bond-length distortion of CoO6 than that of FeO6 is required to form a small hole polaron; hence, Co doping helps to create small hole polarons and to stabilize the structures, as indicated by lower formation energy. Moreover, Co doping enhances the electronic conductivity of LiFePO4 because of Co donor states and also increases the intercalation voltage due to the difference of 3d electron configurations between the Fe2+/Fe3+ states and the Co2+/Co3+ states.