The aim of this book is to illustrate how various electron microscopy techniques can be applied in combination and how new techniques can be developed for specific needs. It provides a snapshot of the state-of-the-art methods used to characterize devices based on electrochemical cells such as solid oxide fuel cells, solid oxide electrolysis, and other energy conversion devices. It also illustrates in a coherent and pedagogical manner how electron microscopy and careful sample preparation can be used to decipher the chemical and physical processes that occur in these devices. These concepts and methodologies are illustrated in case studies, and are transferable to other closely related devices such as batteries and solar cells. With this in mind, this book also presents other upcoming related techniques.The book begins with three introductory chapters on electrochemical cells, electron microscopy and sample preparation providing useful references to comprehensive classic texts on these subjects. The relationship between electrochemical observations of performance and micro/nano-structures is then explored via a series of case studies on technologically relevant issues. With the international pressure to put renewable energy conversion devices on the global market, the material complexity and reducing microstructure scale is increasingly challenging to characterize. Therefore, new electron microscopy and related preparation techniques are in demand to access and understand the local electrocatalytic processes and the limitations to them. This book is intended for students and researchers of energy materials and electrochemistry, and researchers employed by solid oxide fuel cell (SOFC) companies. It is also a valuable resource for academic researchers of electron microscopy and energy conversion materials, and also battery researchers and solar cell researchers.