Constructing two dimensional composite nanosheets with montmorillonite and graphene-like carbon: Towards high-rate-performance PVA based gel polymer electrolytes for quasi-solid-state supercapacitors

A novel functional montmorillonite@graphene-like carbon nanosheets (P-MMT@C) has been synthesized via mutual template method. The P-MMT@C has a special structure, which is composed of porous MMT and graphene-like carbon doped with heteroatoms (N-, S-and O-). The P-MMT@C/PVA gel polymer electrolytes prepared by P-MMT@C as inorganic filler exhibit superior mechanical properties (tensile strength of 0.38 MPa, break elongation of 509.56%) and impressive ionic conductivity (0.133 S cm(-1)). Both the directional channels that formed by the layered structure of MMT and the H-bonding networks that formed by doped heteroatoms of graphene-like carbon layers are able to provide the new ion transportation pathways. Additionally, the assembled supercapacitor with P-MMT@C/PVA gel polymer electrolytes has outstanding rate performance (60.42%, 1-10 A g(-1)) and cycle performance at a high current density. The strategy of constructing two dimensional composite fillers with multiple ion transportation pathways in this work has great potential in improving the performance of gel polymer electrolytes for quasi-solid-state energy storage devices.