Biocompatible carbon nanotube fibers for implantable supercapacitors

The rapid advances in implantable electronic medical devices make supercapacitors highly desirable as power sources. These supercapacitors should be biocompatible, lightweight, miniature and stable without the need for packaging, which unfortunately remains unavailable yet. Here a new family of biocompatible carbon nanotube fibers were synthesized as electrodes to fabricate new supercapacitors that could directly work in physiological fluids including phosphate buffer saline, serum and blood with high energy storage capabilities. For instance, the specific capacitance reached 10.4 F/cm³ or 20.8 F/g that could be maintained by 98.3% after 10,000 cycles in phosphate buffer saline.