Biaxial Stretchability in High-Performance, All-Solid-State Supercapacitor with a Double-Layer Anode and a Faradic Cathode Based on Graphitic-2200 Knitted Carbon Fiber

Large reversible biaxial ( xy ) stretching in energy storage devices is now an urgent requirement for the field of stretchable electronics to enable reliability in practical applications. Here, a fascinating stretching machine is designed and used for xy -stretching of a high-performance supercapacitor device without performance degradation. A trimetallic metal organic framework (MOF)-derived ternary metal oxide on graphitic-2200 knitted carbon fiber (MOF-ZNCO@g-KCF), activated carbon loaded onto drilled knitted carbon fiber (AC@g-KCF-d), and a poly-vinyl alcohol, poly-ethylene oxide, and potassium hydroxide (PVA/PEO/KOH) based hydrogel polymer film are used as a faradic cathode, a double layer anode, and an electrolyte, respectively, to integrate the biaxially stretchable asymmetric supercapacitor (BSASC) device. The fabricated MOF-ZNCO@g-KCF//AC@g-KCF-d BSASC maintains an outstanding performance consistency at different xy -stretched conditions, even after repeated deformations. Notably, after 10 000 galvanostatic charge–discharge cycles, the BSASC in the xy -biaxial stretched condition is retained at 93.7%, and after 100 successive stretch–relax cycles for the same stretching dimension it still retains a 92.48% capacity, demonstrating excellent mechanical and electrochemical stability. The exceptional performance consistency in the xy -stretched position, demonstrates that the BSASC is one of the best performers among the stretchable supercapacitors reported to date.