Coaxial Ni-Ag nanowires network with high stability for stretchable supercapacitors

Despite their excellent electrical and mechanical properties, silver nanowires (AgNWs) are often limited by electrochemical corrosion when used directly in stretchable and wearable energy storage. On the other hand, the electrodes of stretchable energy storage devices are mostly conductive energy storage materials designed as stretchable structures or combined with elastic substrates or relied on conductive polymers. The complex structural design often leads to low specific capacity. Herewith, we designed a coaxial Ni-AgNWs embedded into thermoplastic polyurethane (Ni-AgNWs@TPU) as a stretchable current collector, which effectively protects the AgNWs network by electrodeposition of a nickel layer. We demonstrated a simple activated carbon (A.C.) slurry loading on Ni-AgNWs@TPU stretchable collector, stretchable electrodes with a loading of 25 mg·cm^–2 can be obtained with triethyl phosphate (TEP) as the solvent for A.C. preparation. The stretchable supercapacitors assembled with the gel electrolyte have a high areal capacitance of 489 mF·cm^–2 and are cycled 5000 times at 5 mA·cm^–2 with a capacity retention rate of 92.96%. An excellent capacity retention of 92.77% at a maximum strain of 80% and almost no capacity degradation at 60% strain for 6000 stretch/release cycles evidenced superior mechanical stability.