Active Tensile/Compressive Stress-Regulated Electrochemical Behavior and Mechanism in Electrodes

作者：Xie, Haimei; Guo, Jiangang; Song, Haibin; Shi, Baoqin; Kang, Yilan^*

来源：Energy Technology, 2018, 6(9): 1788-1796.

DOI：10.1002/ente.201700900

• active stress
• cyclic performance
• kinetic performance
• coin-cell structures
• composite electrodes

Coupling of mechanical load and electrochemical behavior of an electrode determines its fading process. Here, active-stress-regulated electrochemical behavior is investigated experimentally. A coin-cell structure with curved spacers is designed to load active tensile/compressive stresses onto Si-composite electrodes to decouple the effect from coupled stress. Electrochemical tests are conducted to measure the cyclic and kinetic performance in electrodes. It is found that active tensile (compressive) stress enhances (inhibits) the electrochemical behavior of Si-composite electrodes, manifesting as improved (worsened) cyclic performance and faster (slower) diffusion and reaction. Furthermore, the extent of enhancement due to tensile stress is greater than the extent of inhibition induced by an equivalent compressive stress. Multi-scale analyses of the regulation mechanism of active stress on electrochemical behavior are performed and show that active tensile stress provides more channels for ion transport and electron migration. It also increases spaces for deformation to achieve multi-scale alleviation of compressive stress, including that originating from particle contact and that along the electrode thickness. Both diffusion and reaction are enhanced in particles and electrodes. Active tensile stress enhances cyclic performance and reduces energy dissipation, while the inhibition mechanism of active compressive stress is the opposite.

• 出版日期2018-9
• 单位天津大学