Direct printing of SWCNT/MnO₂ films for robust ultra-stretchable supercapacitors

The escalating demand for wearable electronics has become a driving force behind the surge in research on energy storage systems capable of powering these novel devices. The increased desire for flexible and elastic electronic devices has amplified demand to overcome the challenges associated with developing high-performance electrical energy sources that maintain electrochemical and mechanical stability under significant strain deformation. In this study, we present a novel approach to fabricate highly flexible supercapacitors composed of single-walled carbon nanotubes (SWCNT) and manganese dioxide (MnO₂), showcasing an impressive areal capacitance of 249 mF/cm². The even distribution of MnO₂ within the SWCNT matrix results in supercapacitors with exceptional electrochemical and mechanical properties. Notably, these supercapacitors can undergo a 400% stretch while retaining 95% of their original capacitance. Moreover, they exhibit stability during electrochemical and mechanical cycling, maintaining 88% capacitance after 10, 000 charging cycles and 85% after 4000 mechanical stretching cycles.