Interstratification-assembled 2D montmorillonite and layered double metal hydroxide heterostructure as all-solid-state polyelectrolyte for wide temperature and long-cycling stability supercapacitors

Although polymerelectrolyte with strong preparation convenience and good electrochemical compatibility has been extensively studied in solid supercapacitors, their narrow operating temperature and poor cycling stability still remain elusive due to the random dispersion of polymer chains. Herein, we report negatively charged sodium-based montmorillonite (Na-MMT) and positively charged layered double metal hydroxide (NiCo-LDHs) nanosheets as raw materials, using simple hydrothermal method and interstratification-assembled strategy to prepare PDADMAC-PSS polyelectrolyte with cross-linking system; the cross-linking points between chains can effectively inhibit the sliding between polymer chains and improve the heat resistance of molecular chains. As a result, the polyelectrolyte possesses a remarkably long cycling stability after 7000 cycles (capacitance retention of 97.4%, 98.5% and 94.8%, respectively) with three [AC, NiCo(OH)2, and PPy] electrodes and achieves a wide operating range of temperature (− 10–90 °C).