Supercapacitors in Bioelectronics: Materials, Biocompatibility, and In Vivo Applications

Supercapacitors are increasingly being explored for bioelectronic systems due to their high power density, rapid charge–discharge capability, and excellent biocompatibility, making them promising for tissue–device interfaces. This review summarizes recent advances in supercapacitor materials and device architectures, with particular emphasis on their electrochemical performance, biocompatibility, and multifunctionality in biological applications. To meet diverse application requirements, various one-dimensional fibers, two-dimensional planar structures, and three-dimensional materials have been developed. These supercapacitors can also be integrated with bioelectronic devices such as biofuel cells, enabling combined bioelectrochemical energy conversion and capacitive energy storage. Importantly, many supercapacitors designed for biomedical use exhibit excellent biocompatibility, and some are even biodegradable, thereby providing a solid foundation for in vivo applications. In addition, supercapacitor-based platforms have been engineered to simultaneously deliver energy and provide electrical stimulation to cells, tissues, and in vivo environments. Consequently, supercapacitor-driven bioelectronics are steadily advancing toward wearable and implantable biomedical devices.