Advancing cryogenic electron microscopy towards the mechanistic understanding of metal electrodes and interphases

Since its introduction to battery research in 2017, cryogenic electron microscopy (cryo-EM) has emerged as a powerful tool for probing the delicate structures of Li metal electrodes and their interphases. It has recently expanded to post-Li (e.g., Na, K, Zn, Mg, Ca, and alloy) metal batteries and anode-free systems, offering new opportunities to understand complex interfacial phenomena. Despite these advances, significant challenges persist in fully leveraging cryo-EM across diverse battery chemistries and architectures. This perspective highlights the capabilities and inherent limitations of cryo-EM for elucidating the mechanisms of Li and post-Li metal deposition, as well as metal–electrolyte interphases in batteries with both liquid and solid electrolytes. Additionally, we present the most recent progress and key challenges in the application of cryo-EM to metal battery research. We also propose perspectives for further advancement, including standardizing workflows, upgrading instrumentation, developing new methodologies, and integrating cryo-EM with complementary characterization techniques to fully harness its potential in the development of next-generation metal batteries.