Feng Zhenhua, Qiu Xiangyun, Chen Xin, Wang Haiyu, Guo Xiangxin
Power & Energy Storage System Research Center, College of Mechanical and Electrical Engineering, Qingdao University, No. 308 Ningxia Road, Qingdao 266071, China.
National Engineering Research Center for Intelligent Electrical Vehicle Power System (Qingdao), No. 308 Ningxia Road, Qingdao 266071, China.
ACS Appl Mater Interfaces. 2024 Aug 14;16(32):42995-43005. doi: 10.1021/acsami.4c09122. Epub 2024 Aug 2.
The use of solid electrolytes (SE) in solid-state batteries holds the promise of achieving higher energy densities and enhancing safety. However, current solid-state batteries face significant interface impedance issues, mainly dealing with the effect of the evolution of the solid-solid interface on ion transport. Semi-solid-state batteries (SSB), containing a small amount of liquid electrolyte, serve as appropriate transitional products in the development process of solid-state batteries. More importantly, the clarity of the relevant interface dynamics can provide theoretical guidance for the subsequent all-solid-state batteries. Therefore, this paper investigates SSB through Electrochemical Impedance Spectroscopy (EIS), primarily employing a combination of theoretical modeling, simulation predictions, and experimental analyses to elucidate the complex electrochemical processes within these batteries. Based on detailed exploration of the complex electrochemical processes within SSB, we have discovered additional electrochemical processes beyond Li penetration through the solid-electrolyte interphase (SEI) film and charge transfer. We attribute the additional electrochemical reaction processes to the resistance present at the SE/SEI interface of SSB on account of numerical analysis and interface characterization. Furthermore, this interface resistance exhibits a trend of initial decrease followed by continuous increase, elucidating the attribution and numerical variations of various impedance components within the EIS. The application of EIS techniques to analyze ion transport processes in SSB serves as a suitable transition toward achieving all-solid-state batteries as well as provides guidance for subsequent interface optimization of solid-state batteries and propels their transition from laboratory experimentation to commercialization.
在固态电池中使用固体电解质（SE）有望实现更高的能量密度并提高安全性。然而，目前的固态电池面临着重大的界面阻抗问题，主要涉及固-固界面演变对离子传输的影响。半固态电池（SSB）含有少量液体电解质，是固态电池开发过程中合适的过渡产品。更重要的是，相关界面动力学的清晰性可为后续的全固态电池提供理论指导。因此，本文通过电化学阻抗谱（EIS）研究半固态电池，主要采用理论建模、模拟预测和实验分析相结合的方法来阐明这些电池内部复杂的电化学过程。基于对半固态电池内部复杂电化学过程的详细探索，我们发现了除锂穿过固体电解质界面（SEI）膜和电荷转移之外的其他电化学过程。基于数值分析和界面表征，我们将这些额外的电化学反应过程归因于半固态电池SE/SEI界面处存在的电阻。此外，这种界面电阻呈现出先减小后持续增加的趋势，阐明了EIS中各种阻抗成分的归属和数值变化。应用EIS技术分析半固态电池中的离子传输过程，是迈向全固态电池的合适过渡，也为固态电池后续的界面优化提供指导，并推动其从实验室实验向商业化转变。
