硅酸盐学报

固态聚合物电解质力学-电化学耦合特性与仿真设计

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李聪 ¹ , 张立发 ¹ , 孙豪 ¹ , 贺耀龙 ¹^,²^,³ , 胡宏玖 ¹^,²

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): 1912-1919

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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) : 1912 -1919

固态聚合物电解质力学-电化学耦合特性与仿真设计

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李聪¹, 张立发¹, 孙豪¹, 贺耀龙¹^,²^,³, 胡宏玖¹^,²

作者信息

^1．上海市应用数学和力学研究所，上海大学力学与工程科学学院，上海 200072

^2．上海市能源工程力学重点实验室，上海 200072

^3．上海市力学信息学前沿科学研究基地，上海 200072

通讯作者:

贺耀龙（1981—），男，博士，讲师。

胡宏玖（1969—），男，博士，教授。

作者简介:

李聪（2001—），男，硕士研究生。

Mechanical-Electrochemical Coupling Characteristics of Solid Polymer Electrolyte and Simulations for All-Solid-State Lithium Batteries

Cong LI¹, Lifa ZHANG¹, Hao SUN¹, Yaolong HE¹^,²^,³, Hongjiu HU¹^,²

Affiliations

^1.Shanghai Institute of Applied Mathematics and Mechanics, School of Mechanics and Engineering Science, Shanghai University, Shanghai 200072, China

^2.Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University, Shanghai 200072, China

^3.Shanghai Frontier Science Center of Mechanoinformatics, Shanghai University, Shanghai 200072, China

Corresponding Author:

HE Yaolong (1981-), male, Ph.D., Lecturer. E-mail: yaolonghe@shu.edu.cn;

HU Hongjiu (1969-), male, Ph.D., Professor. huhongjiu@shu.edu.cn

LI Cong (2001-), male, Master candidate. E-mail: lic2388@shu.edu.cn

出版时间: 2025-07-20 doi: 10.14062/j.issn.0454-5648.20250032

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摘要

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固态聚合物电解质的工程化应用面临室温离子电导率低、力学性能差的突出问题。本工作针对聚氧化乙烯-双氟磺酰亚胺锂（PEO-LiTFSI）体系系列电化学、力学实验，提出了不同温度和机械预变形下材料离子电导率和弹性模量的统一描述方法，并据此开展了含机械预变形处理聚合物电解质的全固态锂电池电化学、力学仿真模拟。结果表明，固态聚合物电解质存在显著的力学-电化学耦合特性。对固态聚合物电解质施加机械预变形，可显著提升材料的离子电导率、弹性模量和屈服强度，且预压缩更为有效，机械预变形下材料内部自由体积增加是其重要微观机制。同时，与未经机械预变形处理的工况相比，经10%~20%机械预压缩处理后的聚合物电解质，其在服役时电解质/电极界面附近的拉应力分布相对更均匀，可使得材料在更大的弹性范围工作，并在保障结构机械完整性的前提下显著提升聚合物基全固态锂电池可使用的倍率范围。

关键词

固态聚合物电解质 / 机械预变形 / 力学-电化学耦合 / 离子电导率 / 服役性能

Abstract

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Introduction

Solid polymer electrolytes (SPEs) are pivotal for advancing all-solid-state lithium batteries (ASSLBs) due to their flexibility, processability, and compatibility with existing manufacturing processes. However, their practical application is hindered due to their low ionic conductivity and insufficient mechanical strength at room temperature. The existing research focuses on enhancing ionic conductivity through lithium salt optimization, polymer modification, or nanoparticle incorporation, the interplay between mechanical deformation and electrochemical performance remains underexplored. Previous studies reported that the mechanical pre-deformation (e.g., stretching or compression) can alter the microstructure of SPEs, thereby affecting ion transport. A unified understanding of how mechanical pre-deformation synchronously improves both ionic conductivity and mechanical properties (i.e., critical for structural integrity during battery operation) is still lacking. This study was to address this gap via systematically investigating the mechanical-electrochemical coupling effects on poly(ethylene oxide)-lithium bis(trifluoromethanesulfonyl)imide (PEO-LiTFSI) SPEs under mechanical pre-deformation. This work was to establish a predictive model for SPE performance optimization and provide guidelines for designing high-performance ASSLBs.

Methods

PEO-LiTFSI membranes were synthesized by dissolving PEO (M_w=600 000) and LiTFSI (mass ratio 1.000∶0.404) in acetonitrile, followed by casting and drying under controlled humidity (H₂O≤0.1 mg/L). The samples were subjected to tensile or compressive pre-strain (i.e., 10%-20% compression, 50%-80% tension) at elevated temperatures (above melting point) by universal testing machines, followed by rapid cooling to room temperature. The ionic conductivity was determined by electrochemical impedance spectroscopy (EIS) in a CHI660E workstation. The elastic modulus and yield strength were measured via quasi-static tensile tests. The free volume changes were analyzed by positron annihilation lifetime spectroscopy (PALS). Then, a coupled electrochemical-mechanical model was proposed in COMSOL to simulate the stress distribution and lithium diffusion in ASSLBs. The model incorporated temperature- and strain-dependent material parameters derived from the related experimental data.

Results and discussion

This study reveals that the mechanical pre-deformation, particularly compression, significantly enhances both the ionic conductivity and mechanical properties of PEO-LiTFSI solid polymer electrolytes (SPEs). The results demonstrate that in the presence of 20% pre-compression, the ionic conductivity is increased by 4.4 times at 20 ℃, while the elastic modulus and yield strength can be enhanced by 1.60 times and 1.45 times, respectively. These enhancements are attributed to the microstructural changes induced by pre-deformation. The results by positron annihilation lifetime spectroscopy (PALS) confirm an 18% increase in normalized free volume (v_f/v_fo), which reduces Li⁺ migration barriers and facilitates ion transport. Polymer chain alignment under compression strengthens interchain interactions, countering a potential mechanical weakening from free volume expansion and improving stress distribution homogeneity. The simulations further validate these findings, showing that pre-compressed SPEs exhibit more uniform tensile stress near the electrolyte/electrode interface, thereby delaying the plastic deformation and extending the elastic working range. Despite a modest 7.7% increase in interfacial stress, the concurrent 17.5% increase in yield strength ensures a mechanical integrity during high-rate operation. In addition, a unified Arrhenius-based model incorporating temperature- and strain-dependent parameters accurately predicts the SPE behavior, with average relative errors of 8.4% for ionic conductivity and 3.6% for elastic modulus, confirming its utility for performance optimization. These results highlight the dual benefits of mechanical pre-compression, i.e., enhancing ion transport while fortifying structural robustness, and provide actionable insights for designing high-performance, durable all-solid-state lithium batteries.

Conclusions

This study demonstrated that the mechanical pre-compression (i.e., 10%-20% strain) could be an effective strategy to simultaneously enhance the ionic conductivity, elastic modulus, and yield strength of PEO-LiTFSI solid polymer electrolytes (SPEs), addressing critical challenges in their engineering application. The improvements could be attributed to the synergistic effects of increased free volume, facilitating Li⁺ ion transport and polymer chain orientation, which strengthening interchain interactions and homogenizes stress distribution. A unified Arrhenius-based model could capture the temperature- and strain-dependent evolution of SPE properties, enabling the predictive optimization for diverse operating conditions. The simulations further revealed that the pre-compressed SPEs exhibited more uniform interfacial stress profiles and higher mechanical resilience, expanding a usable rate capability of all-solid-state lithium batteries while maintaining structural integrity. These findings could establish mechanical pre-deformation as a viable pathway to design high-performance SPEs and advance the development of durable, high-energy-density solid-state batteries.

Key words

solid polymer electrolyte / mechanical pre-deformation / mechano-electrochemical coupling / ionic conductivity / service performance

引用本文

李聪, 张立发, 孙豪, 贺耀龙, 胡宏玖. 固态聚合物电解质力学-电化学耦合特性与仿真设计. 硅酸盐学报, 2025 , 53 (7) : 1912 -1919 . DOI: 10.14062/j.issn.0454-5648.20250032

Cong LI, Lifa ZHANG, Hao SUN, Yaolong HE, Hongjiu HU. Mechanical-Electrochemical Coupling Characteristics of Solid Polymer Electrolyte and Simulations for All-Solid-State Lithium Batteries[J]. Journal of the Chinese Ceramic Society, 2025 , 53 (7) : 1912 -1919 . DOI: 10.14062/j.issn.0454-5648.20250032

基金

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上海市自然科学基金面上项目(23ZR1421800)
国家自然科学基金面上项目(12272213)

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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.0454-5648.20250032

接收时间：2025-01-14
首发时间：2026-10-21
出版时间：2025-07-20

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出版历史

收稿日期：2025-01-14
修回日期：2025-03-02

基金

上海市自然科学基金面上项目(23ZR1421800)

国家自然科学基金面上项目(12272213)

作者信息

^1．上海市应用数学和力学研究所，上海大学力学与工程科学学院，上海 200072

^2．上海市能源工程力学重点实验室，上海 200072

^3．上海市力学信息学前沿科学研究基地，上海 200072

通讯作者:

贺耀龙（1981—），男，博士，讲师。

胡宏玖（1969—），男，博士，教授。

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https://castjournals.cast.org.cn/joweb/gsyxb/CN/10.14062/j.issn.0454-5648.20250032

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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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