Digital Microscale Electrochemical Energy Storage Devices for a Fully Connected and Intelligent World

With the evolving digital era represented by 5G and Internet of Things technologies, microscale electronic terminals will enter every aspect of our daily lives. Meanwhile, they put forward all-around digital requirements for microscale electrochemical energy storage devices (MEESDs), including customizable implementation and precise description, to accurately match these terminals in various scenarios. In this Focus Review, we summarize the current status and latest progress of MEESDs from diverse aspects of key materials, device structures, fabrication processes, functional properties, and system integration in detail. On this basis, existing challenges and future research directions for MEESDs, including evaluation standards, analysis methods, and machine learning, are discussed in brief, through which we can expect to accelerate the development of digital MEESDs as an underlying energy foundation for a fully connected and intelligent world.