固体核磁共振技术解析固态电池离子输运机制研究进展

Progress of ion transport in solid-state battery research based on solid state nuclear magnetic resonance

固态电池具有高能量密度和高安全性的特点,是下一代高比能电池的重要发展方向。固态电解质的离子电导率和固态电池多尺度界面性质共同决定固态电池的电化学性能。相比之下,离子在固态电池界面的迁移相对缓慢,这也是提高电化学性能的关键所在。然而传统表征方法有其局限性,无法有效解析固态电池纳米尺度界面对离子传输的影响。固体核磁共振技术可以原位无损地分析局域结构,并对离子传输动力学进行定量分析。本文基于作者所在团队以及国内外先进研究成果,立足于固态电池的离子传输关键科学问题,从固态电解质的离子电导率以及电极电解质界面出发,介绍分析了固体核磁共振技术在研究离子传输方面取得的研究成果。本文首先对固态电池面临的问题进行总结,其次介绍电池研究中常见的固体核磁共振方法,重点介绍了如何通过固体核磁技术解析固态电解质的晶界、离子迁移路径、复合电解质两相界面对传输机制的影响,以及电极电解质界面接触、(电)化学反应和空间电荷层对界面离子传输机制的影响。最后展望了固体核磁共振技术在未来研究固态电池科学问题方面的重要作用。

Solid-state batteries are the most promising next-generation batteries due to their high-energy density and safety features.The ionic conductivity of solid electrolytes and the interface of solid-state batteries play crucial roles in determining their electrochemical performance.However,intrinsic ion migration across interfaces poses a challenge for achieving optimal electrochemical performance.Owing to the limitations of state-of-the-art characterization methods,it is difficult to analyze Li+transport across interfaces in solid-state batteries.Solid-state nuclear magnetic resonance(ssNMR)can be used to provide an invasive analysis of local structures and a quantitative study of ion transport,making it an important tool for solid-state battery research.This review summarizes recent studies by our team and other groups that have used ssNMR to study solid electrolytes and the electrodeelectrolyte interface.Starting with an overview of the current obstacles in the development of solid-state batteries,this review provides a concise summary of universal ssNMR methods used in battery research.The key factors affecting the ionic conductivity of the solid electrolyte were analyzed,focusing on the grain boundaries,interfacial structures,and ion-diffusion pathways.This review also focuses on understanding the failure process between solid electrolytes and electrodes,and summarizes some modification methods that can contribute to the development of stable interfaces in solid-state batteries.Furthermore,this review provides a comprehensive summary of the role of space charges at solid electrolyte-electrode interfaces,which are key factors affecting the electrochemical performance of solid-state batteries.Finally,this review discusses future challenges,perspectives,and potential for further studies using ssNMR in the field of solid-state batteries.