Dispersed nickel-cobalt double metal hydroxide self-assembled with polystyrene sulfonic acid polyelectrolyte for the preparation of carbon solid solid supercapacitors with wide temperature range and long cycle stability

Although polyelectrolytes with good electrochemical compatibility have been widely used in all solid-state supercapacitors, the random dispersion of polymer chains results in a narrow operating temperature range, which limits its further application. Herein, through the electrostatic attraction assembly strategy, the negatively charged polystyrene sulfonic acid (PSS) and the positively charged layered nickel-cobalt double hydroxide (NiCoLDH) nanosheets are synthesized into PSS/NiCo-LDH composite electrolyte. Meanwhile, the polyelectrolyte shows a wide temperature application range (20-80 degrees C) and excellent electrochemical cycle stability in solid supercapacitor (capacitance retention rate reaches 96.2% after 5000 cycles) based on activated-carbon electrodes. The remarkable thermal stability and electrochemical performance are mainly attributed to the addition of NiCo-LDH, which is not only limit the thermal decomposition of PSS molecular chains, but also accelerate the migration rate of electrolyte ions. This work opens a way for the preparation of polyelectrolyte with wide temperature range and long cycle stability for application in solid-state supercapacitors.