“Integrated Interlocking” architecture improving cycle stability of supercapacitors based on Self-Supporting electrodes

Abstract

Flexible supercapacitors (FSCs) are promising energy storage devices for emerging wearable electronics. However, the design of a reasonable architecture at the device level is still lacking, which restricts the comprehensive improvement of the performance of FSCs. Here, an FSC with “integrated interlocking” architecture has been created. For such an architecture, two metal-oxide-based self-supporting electrodes sandwich a polyolefin elastic skeleton, and the zwitterionic gel (ZIG) electrolyte is simultaneously polymerized inside this skeleton and the self-supporting electrodes to in-situ assemble an asymmetric FSC. This elastic skeleton solves the problem of the mechanical properties degradation of ZIG under high swelling ratio, resulting in 60 times increase in tensile strength and 4.8 times increase in elongation at break. In addition, the ZIG is fully contacted with the nanosized active materials to form an ionomer encapsulation structure, which comprehensively improves the electrochemical performance of the device, especially the cycle stability (86.4% capacitance retention after 12,000 charge–discharge cycles).