Epidermal Supercapacitor with High Performance

Recent development in epidermal and bionic electronics systems has promoted the increasing demand for supercapcacitors with micrometer‐thickness and good compatibility. Here, a highly flexible free‐standing epidermal supercapacitor (SC‐E) with merely 1 μm thickness and high performance is developed. Single‐walled carbon nanotube/poly(3,4‐ethylenedioxythiophene) hybrid films with unique inner‐connected reticulation are adopted as electrodes for ultrathin structure and high electric conductivity. Then, based on two substrates with different surface energies, a stepwise lift‐off method is presented to peel off the ultrathin integrated supercapacitor from the substrates nondestructively. As a result of the high conductive hybrid electrodes and the thin electrolyte layer, the as‐designed supercapacitors (based on the total mass of two electrodes) achieve a good capacitance of 56 F g⁻¹ and a superhigh power density of 332 kW kg⁻¹, which manifest superior performance in contrast to the other devices fabricated by traditional electrodes. Meanwhile, the ultrashort response time of 11.5 ms enables the epidermal supercapacitor (SC‐E) work for high‐power units. More importantly, the free‐standing structure and outstanding flexibility (10⁵ times bending) endow the SC‐E with excellent compatibility to be integrated and work in the next generation of smart and epidermal systems.