A novel stretchable supercapacitor electrode with high linear capacitance

Conventional flexible supercapacitors that can work under consecutive bending, folding and even twisting without performance degradation have been widely reported. Nevertheless, these devices can hardly be used under large tensile strain due to limited stretchability. In this regard, the application field of flexible supercapacitors can be remarkably broaden if they are designed as stretchable power supplies for wearable electronic devices. Herein, we report a stretchable supercapacitor electrode through in situ synthesis of hierarchical carbon tubular nanostructures (hCTNs) and conducing polyaniline (PANI) onto stainless steel spring (SSS) which features both excellent conductivity and high stretchability. The as-prepared helical electrode exhibits considerable specific capacitance of 277.8 F g(-1) at 1 A g(-1) and unprecedented linear capacitance of 402.8 mF cm (-1) at the current density of 1 mA cm(-1) , which is much higher than most previously reported literatures. Besides, electrochemical performance of this electrode can be maintained under various mechanical loading such as compressing and bending. Additionally, 100% tensile strain of electrode is successfully demonstrated without sacrificing its electrochemical performance.