Advances in micro lithium-ion batteries for on-chip and wearable applications

Abstract Miniature power sources have gained widespread attention and accelerated progress with portable, wearable, and integrated electronic technologies. Micro lithium-ion batteries ( μ LIBs) featured small size, lightweight, high capacity, and long cycle life, which also offer stability, safety, and compatibility with microfabrication, make them the ideal choice for energy storage. Researchers have engaged in the performance optimization and application expansion of μ LIBs, especially in the on-chip μ LIBs with compatible integration for microdevices and flexible μ LIBs for wearable applications. This paper reviews the working principles, performance metrics, and design methodologies of μ LIBs, highlighting the advantages of the architecture design. Typical materials and fabrication methods are introduced, and their effects on the device performance and system integration are analyzed. The developments of μ LIBs are summarized from the perspective of 3D architecture design to the on-chip and wearable applications. At last, the challenges and the prospects that inspire further research and development of μ LIBs are concluded.