硅酸盐学报

协同输运增强离子输运性能：以榍石型硅酸钽锂为例

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李燊 ¹ , 邹喆乂 ¹ , 何冰 ² , 施思齐 ³^,⁴

硅酸盐学报 | 电化学储能材料计算与设计专题—研究论文 2025,53(7): 1929-1937

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硅酸盐学报 |电化学储能材料计算与设计专题—研究论文 2025 , 53 (7) : 1929 -1937

协同输运增强离子输运性能：以榍石型硅酸钽锂为例

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李燊¹, 邹喆乂¹, 何冰², 施思齐³^,⁴

作者信息

^1．湘潭大学材料科学与工程学院，湖南湘潭 411105

^2．上海大学计算机工程与科学学院，上海 200444

^3．上海大学核电关键材料全国重点实验室&材料科学与工程学院，上海 200444

^4．上海大学材料基因组工程研究院，上海 200444

通讯作者:

邹喆乂（1990—），男，博士；

施思齐（1978—），男，博士，教授。

作者简介:

李燊（1999—），男，硕士研究生。

Boosting Ionic Transport Performance through Correlated Migration: A Case Study of Titanite-Type LiTaSiO₅

Shen LI¹, Zheyi ZOU¹, Bing HE², Siqi SHI³^,⁴

Affiliations

^1.School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105, Hunan, China

^2.School of Computer Engineering and Science, Shanghai University, Shanghai 200444, China

^3.State Key Laboratory of Materials for Advanced Nuclear Energy & School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China

^4.Materials Genome Institute, Shanghai University, Shanghai 200444, China

Corresponding Author:

ZOU Zheyi (1990-), male, Ph.D. E-mail: zyzou@xtu.edu.cn;

SHI Siqi (1978-), male, Ph.D, Professor. sqshi@shu.edu.cn

LI Shen (1999-), male, Master candidate. E-mail: 202221551497@smail.xtu.edu.cn

出版时间: 2025-07-20 doi: 10.14062/j.issn.0454-5648.20250350

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摘要

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固态锂电池因其高能量密度和安全性被视为传统锂离子电池的重要替代方案，而开发高离子电导率的固体电解质是实现其应用的关键。榍石型LiTaSiO₅是一种新型氧化物固体电解质，通过Ta⁵⁺位掺Zr⁴⁺可引入过量锂离子，促进协同输运，进而显著提升电导率。然而，其中的锂离子分布、协同输运与离子输运性能之间的关系仍需深入探究。本工作基于第一性原理分子动力学（AIMD）模拟，研究了Li₁₊_xTa_1-_xZr_xSiO₅（x = 0，0.125）体系的离子输运性质。结果表明，LiTaSiO₅中的锂离子传输呈现各向异性，主要沿［101］方向的It2-Li1/It4-It7-It3-It7-Li1/It4-It2通道进行传输。Zr掺杂后，锂离子浓度增加，锂离子在高能位（It2/It3）的占据率增加，锂离子分布更无序，构型熵增大。这种锂离子分布促进了低能垒协同跳跃，使体系协同跳跃率增加，总激活能降低，同时扩散系数明显增大。本工作从原子尺度揭示了锂离子分布、协同输运以及离子输运性能之间的关联规律，为具有高离子电导率的固体电解质设计提供了理论依据。

关键词

氧化物固体电解质 / 构型熵 / 协同输运 / 分子动力学

Abstract

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Introduction

Solid-state lithium batteries are regarded as a promising alternative to traditional lithium-ion batteries due to their high energy density and safety. The development of solid electrolytes with high ionic conductivity is key to their application. The lithium-ion transport mechanisms in solid electrolytes can be categorized into single-ion migration and multi-ion correlated migration. Generally, multi-ion correlated migration can significantly reduce energy barriers compared to single-ion migration, making the promotion of correlated migration a crucial principle in designing solid electrolyte materials with high ionic conductivity. Titanite-type LiTaSiO₅ is a new oxide solid electrolyte, in which Zr⁴⁺ doping at Ta⁵⁺ site introduces excess lithium ions, facilitating correlated migration and significantly improving ionic conductivity. However, the relationship between lithium-ion distribution, correlated migration, and ionic transport properties still require in-depth investigation. In this study, ab initio molecular dynamics (AIMD) simulations were employed to investigate the possible Li sites and migration channels in the monoclinic titanite-type Li₁₊_xTa_1-_xZr_xSiO₅(x = 0, 0.125) systems. The relationships between lithium-ion distribution, the degree of correlated migration, and ionic transport properties were also elucidated.

Methods

AIMD simulations were performed using the Vienna ab initio simulation package (VASP) with the plane wave projector augmented (PAW) method and the Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional. For the pristine LiTaSiO₅ (ICSD No. 39648, space group P2₁/c), a 2×2×2 supercell was constructed, containing 32 formula units (256 atoms total). For the Zr-doped system, four Ta⁵⁺ were substituted with Zr⁴⁺, with four additional Li⁺ ions incorporated to maintain charge neutrality. AIMD simulations were carried out for the canonical (NVT) ensemble using a Nosé-Hoover thermostat at four elevated temperatures (800, 1000, 1200, and 1400 K) with a time step of 2 fs. To enhance computational efficiency, the plane-wave basis set was determined with a cutoff energy of 400 eV and integration in reciprocal space was performed at the Γ-point only. All the structures were heated from 100 K to targeted temperatures by velocity scaling over 2 ps, and then equilibrated at the desired temperature for 20 ps. The analysis of possible Li sites, jump events, and diffusion properties based on AIMD data was performed using our in-house developed code, which is integrated into our group's computational platform for electrochemical energy storage materials design (bmaterials.cn).

Results and discussion

The framework structure of the monoclinic titanite-type LiTaSiO₅ consists of SiO₄ tetrahedra and TaO₆ octahedra. Through crystal structure analysis, we identified 11 distinct interstitial sites (It1-Itl1), where the It1 site corresponds to the Li1 lattice site while It2 and It3 sites align with two previously reported potential interstitial sites. Lithium ion migration exhibits strong preference for specific channels. At 800 K, 81.8% of jumps occur along the It2-Li1/It4-It7-It3-It7-Li1/It4-It2 channel ([101] direction) through elementary channels (Li1-It2, Li1-It7, It2-It4, It3-It7 and It4-It7), clearly identifying this as the optimal long-range migration channel. The non-unity occupation probabilities at all sites indicate Li⁺ disorder, with primary Li⁺ distribution at Li1, It2, It3, It4, and It7 sites. Previous studies confirm that Li1 is the lowest-energy stable site, while It2 and It3 serve as saddle points in the energy landscape. Zr doping significantly alters the Li⁺ distribution by increasing the Li⁺ concentration and promoting occupation of higher-energy sites. At 800 K, Li1 occupancy decreases from 41.8% to 33.1%, while It2 and It3 occupancies increase dramatically from 7.2% to 27.9% and from 7.4% to 24.3%, respectively. This redistribution, accompanied by increased configurational entropy, enhanced Li⁺ disorder and promotes low-energy-barrier correlated migration. As a result, the correlated migration percentage increases, the overall activation energy decreases, and the Li⁺ diffusion coefficient improves significantly.

Conclusions

The main conclusions of this study are summarized as following. The LiTaSiO₅ unit cell contains 11 distinct types of interstitial sites and shows anisotropic lithium-ion transport along the [101] direction through the It2-Li1/It4-It7-It3-It7-Li1/It4-It2 channel. After Zr doping, the lithium-ion concentration increases, leading to higher occupancy of lithium ions at high-energy sites (It2/It3), more disordered lithium-ion distribution, and an increase configurational entropy. This Li distribution enhances the probability of low-energy-barrier correlated migration, resulting in a higher correlated migration percentage, reduced overall activation energy, and significantly improved ionic transport performance.

The methodologies employed in this study are applicable to inorganic crystalline solid electrolytes with stable framework structures, which have been successfully applied in previous studies to several representative lithium/sodium solid electrolytes, such as LiTa₂PO₈ and Na₃Zr₂Si₂PO₁₂. However, these methods rely on the framework ions to identify the positions of lithium ions during the migration processes, making them unsuitable for certain specific solid electrolyte systems, such as amorphous solid electrolytes or those exhibiting the polyanion rotation effect.

Key words

oxide solid electrolyte / configurational entropy / correlated migration / molecular dynamics

引用本文

李燊, 邹喆乂, 何冰, 施思齐. 协同输运增强离子输运性能：以榍石型硅酸钽锂为例. 硅酸盐学报, 2025 , 53 (7) : 1929 -1937 . DOI: 10.14062/j.issn.0454-5648.20250350

Shen LI, Zheyi ZOU, Bing HE, Siqi SHI. Boosting Ionic Transport Performance through Correlated Migration: A Case Study of Titanite-Type LiTaSiO₅[J]. Journal of the Chinese Ceramic Society, 2025 , 53 (7) : 1929 -1937 . DOI: 10.14062/j.issn.0454-5648.20250350

基金

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国家自然科学基金(52102313; 92472207)
湖南省自然科学基金(2023JJ40635)
湖南省研究生科研创新项目(QL20230150)

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2025年第53卷第7期

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文章信息

doi: 10.14062/j.issn.0454-5648.20250350

接收时间：2025-04-30
首发时间：2026-10-21
出版时间：2025-07-20

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收稿日期：2025-04-30
修回日期：2025-05-15

基金

国家自然科学基金(52102313; 92472207)

湖南省自然科学基金(2023JJ40635)

湖南省研究生科研创新项目(QL20230150)

作者信息

^1．湘潭大学材料科学与工程学院，湖南湘潭 411105

^2．上海大学计算机工程与科学学院，上海 200444

^3．上海大学核电关键材料全国重点实验室&材料科学与工程学院，上海 200444

^4．上海大学材料基因组工程研究院，上海 200444

通讯作者:

邹喆乂（1990—），男，博士；

施思齐（1978—），男，博士，教授。

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https://castjournals.cast.org.cn/joweb/gsyxb/CN/10.14062/j.issn.0454-5648.20250350

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2种不同金属材料的力学参数

科 Family	属数 Number of genus	种数 Number of species	占总种数比例 Percentage of total species (%)	属 Genus	种数 Number of species	占总种数比例 Percentage of total species (%)
鹅膏菌科Amanitaceae	2	11	5.26	鹅膏菌属 Amanita	10	4.78
小菇科 Mycenaceae	2	12	5.74	丝盖伞属 Inocybe	5	2.39
多孔菌科 Polyporaceae	8	14	6.70	蜡蘑属 Laccaria	5	2.39
红菇科 Russulaceae	3	23	11.00	小皮伞属 Marasmius	6	2.87
				小菇属 Mycena	11	5.26
				光柄菇属 Pluteus	5	2.39
				红菇属 Russula	17	8.13
				栓菌属 Trametes	5	2.39

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