Stretchable fiber-shaped asymmetric supercapacitors with ultrahigh energy density

Fiber-shaped asymmetric supercapacitors (FASCs) have attracted considerable attention due to their potential application in portable and wearable electronics. Although high stretchability have been achieved in fiber-shaped supercapacitors, low energy density severely restricts their practical applications. This study develops a simple and cost-effective method to synthesize highly capacitive hierarchically-structured MnO2@PEDOT:PSS@oxidized carbon nanotube fibers (MnO2@PEDOT:PSS@OCNTF) positive electrode and flower-like MoS2 nanosheets@CNTF (MoS2@CNTF) negative electrode. Their intriguing structural features allowed us to successfully fabricate a prototype stretchable FASC with a maximum operating voltage of 1.8 V. Due to the synergy of the MnO2@PEDOT:PSS@OCNTF and MoS2@CNTF, the optimized stretchable FASC device exhibits a remarkable specific capacitance of 278.6 mF/cm(2) and a superior energy density of 125.37 mu Wh/cm(2), which are higher than those of any reported state-of-the-art fiber-shaped supercapacitors. In addition, the device possesses outstanding stretchability, as it maintains a capacitance retention of 92% after stretching at a strain of 100% for 3000 cycles. These stretchable FASCs have great potential as power sources for next-generation portable and wearable electronics.