近日，上海大学Bo Lu团队报道了从结构异质性到力学弱化：厚电极中的尺寸效应。相关论文发表在2026年3月24日出版的《理论与应用力学快报》杂志上。

通过厚锂离子电池电极追求更高的能量密度，从根本上挑战了它们在制造过程中增加的开裂易感性。研究表明，这种失败源于明显的尺寸效应。随着活性层变厚，干燥引起的粘结剂迁移导致孔隙度从上到下的梯度变大。这种放大的细观结构非均质性直接控制宏观力学弱化。

研究组开发了一种机器人方法，在软基板上制作无损伤、独立的厚有源层，用于精确的拉伸测试，证实了随着厚度的增加，模量和强度都有系统的降低。基于细观结构的有限元模拟建立了直接的耦合关系，表明孔隙度梯度升高了局部应力集中，降低了有效承载能力。通过建立细观结构与宏观性能之间的机制联系，该研究为设计高能量密度厚电极提供了重要的基础。

附：英文原文

Title: From structural heterogeneity to mechanical weakening: size effect in thick electrodes

Author: Jinyang Huang, Huadong Gao, Yicheng Song, Bo Lu, Junqian Zhang

Issue&Volume: 2026-03-24

Abstract: The pursuit of higher energy density through thick lithium-ion battery electrodes is fundamentally challenged by their increased susceptibility to cracking during fabrication. This work reveals that this failure stems from a pronounced size effect. As the active layer thickens, drying-induced binder migration creates a steeper gradient in porosity from top to bottom. This amplified mesostructural heterogeneity directly governs the macroscopic mechanical weakening. We developed a robust method using a soft substrate to fabricate damage-free, free-standing thick active layers for accurate tensile testing, which confirmed the systematic reduction in both modulus and strength with increasing thickness. Mesostructure-based finite element simulations establish a direct causal link, showing that the porosity gradient elevates local stress concentrations and reduces the effective load-bearing capacity. By establishing a mechanistic link between mesostructure and macroscopic performance, this study provides a critical foundation for designing high-energy-density thick electrodes.

DOI: 10.1016/j.taml.2026.100676

Source: http://taml.cstam.org.cn/article/doi/10.1016/j.taml.2026.100676pageType=en