中国物理B ›› 2023, Vol. 32 ›› Issue (6): 68201-068201.doi: 10.1088/1674-1056/acc05d

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Structural, electronic, and Li-ion mobility properties of garnet-type Li7La3Zr2O12 surface: An insight from first-principles calculations

Jing-Xuan Wang(王靖轩)1, Bao-Zhen Sun(孙宝珍)1,2,†, Mei Li(李梅)1, Mu-Sheng Wu(吴木生)1, and Bo Xu(徐波)1,‡   

  1. 1 Department of Physics, Laboratory of Computational Materials Physics, Jiangxi Normal University, Nanchang 330022, China;
    2 Institute of Advanced Scientific Research(iASR)&Key Laboratory of Functional Small Molecules for Ministry of Education, Jiangxi Normal University, Nanchang 330022, China
  • 收稿日期:2022-12-13 修回日期:2023-01-29 接受日期:2023-03-02 出版日期:2023-05-17 发布日期:2023-06-05
  • 通讯作者: Bao-Zhen Sun, Bo Xu E-mail:bzsun@jxnu.edu.cn;bxu4@mail.ustc.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 12064015 and 12064014).

Structural, electronic, and Li-ion mobility properties of garnet-type Li7La3Zr2O12 surface: An insight from first-principles calculations

Jing-Xuan Wang(王靖轩)1, Bao-Zhen Sun(孙宝珍)1,2,†, Mei Li(李梅)1, Mu-Sheng Wu(吴木生)1, and Bo Xu(徐波)1,‡   

  1. 1 Department of Physics, Laboratory of Computational Materials Physics, Jiangxi Normal University, Nanchang 330022, China;
    2 Institute of Advanced Scientific Research(iASR)&Key Laboratory of Functional Small Molecules for Ministry of Education, Jiangxi Normal University, Nanchang 330022, China
  • Received:2022-12-13 Revised:2023-01-29 Accepted:2023-03-02 Online:2023-05-17 Published:2023-06-05
  • Contact: Bao-Zhen Sun, Bo Xu E-mail:bzsun@jxnu.edu.cn;bxu4@mail.ustc.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 12064015 and 12064014).

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摘要： Garnet-type Li7La3Zr2O12 (LLZO) is a promising solid-state electrolyte for Li-ion batteries, but Li-dendrite's formation greatly limits the applications. In this paper, we systematically investigate the stability, electronic properties, and Li-ion mobility of the LLZO surface by the first-principles calculations. We consider the (110) and (001) slab structures with different terminations in the t- and c-LLZO. Our results indicate that both (110) and (001) surfaces prefer to form Li-rich termination due to their low surface energies for either t- or c-LLZO. Moreover, with the decrease of Li contents the stability of Li-rich surfaces is improved initially and degrades later. Unfortunately, the localized surface states at the Fermi level can induce the formation of metallic Li on the Li-rich surfaces. In comparison, Li/La-termination has a relatively low metallic Li formation tendency due to its rather low diffusion barrier. In fact, Li-ion can spontaneously migrate along path II (m Li3→Li2) on the Li/La-T(001) surface. In contrast, it is more difficult for Li-ion diffusion on the Li-T(001) surface, which has a minimum diffusion barrier of 0.50 eV. Interestingly, the minimum diffusion barrier decreases to 0.34 eV when removing four Li-ions from the Li-T(001) surface. Thus, our study suggests that by varying Li contents, the stability and Li-ion diffusion barrier of LLZO surfaces can be altered favorably. These advantages can inhibit the formation of metallic Li on the LLZO surfaces.

关键词: solid-state electrolyte, Li7La3Zr2O12 (LLZO) surface, Li-ion migration, first-principles calculations

Abstract: Garnet-type Li7La3Zr2O12 (LLZO) is a promising solid-state electrolyte for Li-ion batteries, but Li-dendrite's formation greatly limits the applications. In this paper, we systematically investigate the stability, electronic properties, and Li-ion mobility of the LLZO surface by the first-principles calculations. We consider the (110) and (001) slab structures with different terminations in the t- and c-LLZO. Our results indicate that both (110) and (001) surfaces prefer to form Li-rich termination due to their low surface energies for either t- or c-LLZO. Moreover, with the decrease of Li contents the stability of Li-rich surfaces is improved initially and degrades later. Unfortunately, the localized surface states at the Fermi level can induce the formation of metallic Li on the Li-rich surfaces. In comparison, Li/La-termination has a relatively low metallic Li formation tendency due to its rather low diffusion barrier. In fact, Li-ion can spontaneously migrate along path II (m Li3→Li2) on the Li/La-T(001) surface. In contrast, it is more difficult for Li-ion diffusion on the Li-T(001) surface, which has a minimum diffusion barrier of 0.50 eV. Interestingly, the minimum diffusion barrier decreases to 0.34 eV when removing four Li-ions from the Li-T(001) surface. Thus, our study suggests that by varying Li contents, the stability and Li-ion diffusion barrier of LLZO surfaces can be altered favorably. These advantages can inhibit the formation of metallic Li on the LLZO surfaces.

Key words: solid-state electrolyte, Li7La3Zr2O12 (LLZO) surface, Li-ion migration, first-principles calculations

中图分类号:  (Lithium-ion batteries)

  • 82.47.Aa
71.15.Mb (Density functional theory, local density approximation, gradient and other corrections) 61.66.Fn (Inorganic compounds) 68.35.Md (Surface thermodynamics, surface energies)