Feng Shihao, Wang Zhixing, Zhang Guoshang, Yue Pengfei, Pan Wengao, Lu Qiongqiong, Guo Huajun, Li Xinhai, Yan Guochun, Wang Jiexi
Institute of Materials, Henan Academy of Sciences, Zhengzhou, 450046, P. R. China.
School of Metallurgy and Environment, Central South University, Changsha, 410083, P. R. China.
Phys Chem Chem Phys. 2024 Oct 17;26(40):25881-25889. doi: 10.1039/d4cp02375g.
Materials with Hexagonal Close Packed (HCP) anionic configuration contain promising lithium-ion conductors. In the HCP anionic structure, when the non-lithium cations occupy the octahedral sites (the important diffusion channels for lithium ions), it is not known whether the nature of fast lithium-ion diffusion will be retained. This work systematically studied the lithium-ion diffusion properties of LiNbO as well as its doped phases on the basis of first-principles calculations. The calculation results show that the lithium-ion conductivity of LiNbO is 0.008 mS cm at room temperature, while the doped phase LiNbWO with W doping at the Nb sites possesses a higher lithium-ion conductivity of 0.28 mS cm at room temperature and an activation energy of 0.34 eV. The lithium-ion diffusion mechanism in LiNbO and its doped phase involves concerted migration; besides, they are poor conductors of electrons regardless of whether doping is applied. In addition, W doping increases the reduction limit of the electrochemical window due to its strong oxidizing property; therefore, an artificial SEI film needs to be applied to reduce interfacial decomposition. The discovery and characterization of the new fast lithium-ion conductor LiNbWO provide theoretical guidance for the development of new solid electrolytes.
