Recent progress in biocompatible miniature supercapacitors

With the advancement of wearable and implantable health and medical electronics, biocompatible miniature energy storage devices were developed rapidly. In particular, biocompatible miniature supercapacitors (BMSCs) have the advantages of conventional supercapacitors, such as high-power density, fast charging/discharging rate, and long operating lifetime, as well as strong selectivity of biocompatible materials. They are expected to play an important role in personalized electronic integration systems. Biocompatibility involves the biosafety of materials and relates to the mechanics and geometrical forms. For example, BMSCs should be thin and compact, ensuring ease of portability and comfort for users. They should also be flexible and stretchable to conform to the skin or tissue, providing stable power to electronics even under deformation. Furthermore, biodegradability/ bioabsorbability ensures they are both body- and environment-friendly. This review summarizes the recent research progress of BMSCs as wearable and implantable energy storage devices, including the basic requirements and the selection of the components. Additionally, the advanced applications of BMSCs in multifunctional integration systems for real-time health monitoring and medical treatment are introduced, along with the associated challenges and prospects.