电化学阻抗谱(electrochemical impedance spectroscopy, EIS)已在电化学能源领域得到广泛的应用，如燃料电池、电池、超级电容器、电解水/二氧化碳等。为了更好地发挥EIS的诊断功能，文章系统地综述了EIS的基础理论、测量技术、发展趋势，以及在电化学能源技术中的应用，并着重阐明了如何理解以下四个核心问题：(1)什么是EIS(What)？(2)为什么需要EIS(Why)？(3)如何实现EIS诊断(How)？(4)EIS能力边界在哪里(Where)？为了用好EIS技术，必须清楚：EIS可以做什么，EIS不可以做什么，EIS擅长做什么。尽管EIS不是无所不能，但是如果能被合理运用，它的价值和潜力将会得到更好发挥，尤其在电化学能源技术领域。

Electrochemical impedance spectroscopy (EIS) has been widely used in the field of electrochemical energy technologies such as fuel cells, batteries, supercapacitors, electrolysis of H 2 O and CO 2 . This paper systematically reviews the basic theory of EIS, measurement technology, development trend, and application in electrochemical energy technology, and clarifies the accurate understanding of the following four core issues: (1) What is EIS? (2) Why do you need EIS? (3) How to implement EIS diagnosis?
(4) What are capability boundaries for EIS? In order to appropriately and accurately use EIS technique, it must be clear about its
capability boundaries: what EIS can do, what EIS can’t do, and what EIS is good at. EIS is obviously not omnipotent, however its
value and potential will be fully reflected if used correctly, especially for electrochemical energy technologies.