Eco-Degradable and Flexible Solid-State Ionic Conductors by Clay-Nanoconfined DMSO Composites

Abstract

Solid-state electrolytes can alleviate the safety issues of electrochemical energy systems related to chemical and thermal instabilities of liquid electrolytes. While a liquid provides seamless ionic transport with almost perfect wettability between electrodes, a solid-state electrolyte needs to demonstrate at least comparable electrochemical performance to liquid electrolytes as well as mechanical robustness and flexibility. Here, the facile preparation of montmorillonite (MMT)/dimethyl sulfoxide (DMSO) nanocomposites is reported, which show high ionic conductivities, mechanical strengths, and thermal stabilities by forming nacre-mimetic "brick-and-mortar" structures. The molecularly confined structures of DMSO are confirmed by X-ray diffraction peaks with d-spacings of interplanar spacing that are slightly larger than MMTs. The MMT/DMSO composites have mechanical strengths and toughnesses of 55.3 +/- 4.8 MPa and 210.2 +/- 32.6 kJ m(-2), respectively. The ionic conductivity is approximate to 2 x 10(-4) S cm(-1) at room temperature, and their thermal stability is in the range of -100 to 120 degrees C. The optical translucency, on-demand eco-degradability, and solution processability together make the MMT/DMSO composites unique materials with a wide range of solid-state electrochemical applications including batteries.