Toward Soft Skin-Like Wearable and Implantable Energy Devices

The development of ultra-compliant power sources is crucial for their seamless integration with next-generation skin-like wearable and implantable biomedical systems for long-term health monitoring. Toward this goal, stretchable energy storage and conversion devices (ESCDs), including supercapacitors, lithium-ion batteries (LIBs), solar cells, and generators are now attracting intensive worldwide research efforts. The purpose of this review is to discuss the latest achievements in the development of such stretchable energy devices in the context of biomedical applications. We first review the viable strategies and methodologies of fabricating stretchable energy storage and conversion devices. Then, we focus on description of various types of soft energy devices from a materials point of view. Furthermore, we discuss the challenges and opportunities in the design of truly conformal soft energy systems, including various key parameters, such as energy density, stability, and scalability.