石榴石型Li7La3Zr2O12固态电解质的最优锂空位浓度

doi:10.15541/jim20260225

摘要/Abstract

摘要： 精准调控锂空位浓度对于最大化石榴石型Li₇La₃Zr₂O₁₂ (LLZO)固态电解质的离子电导率至关重要。然而,传统的高温合成方法不可避免地会引入寄生杂质(如来自氧化铝坩埚的Al³⁺),从而极大地扰乱其本征的缺陷化学。因此,锂空位与离子传输之间的基础构效关系一直未能得到明确的阐释。为了揭示真实的离子传输机制,本研究采用了一种严格无污染的烧结策略,通过引入定制的微观结构模型以解耦晶粒尺寸和晶界效应等形貌干扰,系统研究了一系列Nb⁵⁺掺杂(掺杂量为0.2~0.7 pfu)LLZO的结晶学演变与传输动力学。研究结果明确表明,在纯净、无杂质的晶格中,当锂空位浓度处于0.45 pfu的最优值时,室温离子电导率达到峰值。这项工作不仅确定了锂石榴石中实现超快离子传输所需的本征空位指标,也为设计高性能固态电解质奠定了严谨的晶体学基础。

关键词: 石榴石固态电解质, 锂空位浓度, Nb掺杂, 迁移动力学

Abstract: Precisely modulating the lithium vacancy concentration is critical for maximizing the ionic conductivity of garnet-type Li₇La₃Zr₂O₁₂ (LLZO) solid electrolytes. However, conventional high-temperature synthesis inevitably introduces parasitic impurities (e.g., Al³⁺ from alumina crucibles), which profoundly perturb the intrinsic defect chemistry. Consequently, the fundamental structure-property relationship between lithium vacancies and ionic transport remains obscured. To unveil the genuine ion-transport mechanism, we employ a strictly contamination-free sintering strategy. By integrating a tailored microstructural model to decouple morphological interferences such as grain size and boundary effects, we systematically investigate the crystallographic evolution and transport kinetics in a series of Nb⁵⁺-doped LLZO (0.2-0.7 per formula unit, pfu). Our findings unambiguously demonstrate that within a pristine, impurity-free lattice, the room-temperature ionic conductivity peaks at an optimal lithium vacancy concentration of exactly 0.45 pfu. This work not only identifies the intrinsic vacancy metric required for ultrafast ion transport in lithium garnets but also establishes a rigorous crystallographic foundation for the rational design of high-performance solid electrolytes.

Key words: garnet-type solid electrolyte, lithium vacancy concentration, Nb doping, transport kinetics

中图分类号:

TM912

唐佳文, 黄晓, 田冰冰. 石榴石型Li₇La₃Zr₂O₁₂固态电解质的最优锂空位浓度[J]. 无机材料学报, DOI: 10.15541/jim20260225.

TANG Jiawen, HUANG Xiao, TIAN Bingbing. Optimum Li-site Vacancy in Garnet-type Li₇La₃Zr₂O₁₂ Solid Electrolyte[J]. Journal of Inorganic Materials, DOI: 10.15541/jim20260225.

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石榴石型Li₇La₃Zr₂O₁₂固态电解质的最优锂空位浓度

Optimum Li-site Vacancy in Garnet-type Li₇La₃Zr₂O₁₂ Solid Electrolyte

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