Flexible supramolecular polymer proton conductors with high mechanical-conductive decoupling ability

Abstract

Achieving the decoupling of ion transport and mechanical relaxation, also known as superionic conduction, is a crucial goal for electrolyte materials in energy and electronics technologies. However, constructing highly efficient ionic conductive pathways to overcome the trade-off that restrained segments reduce ionic conduction in polymer electrolytes still remains challenging. Given the non-covalent binding nature of supramolecular polymers, which offers advantages such as dynamic segments and easy integration of ionophilic units, here we present the creation of supramolecular polymer proton conductors (SPPCs) based on deep eutectic solvents (DESs) and polyoxometalate (POM) nanoclusters as hybrid monomers. By innovatively incorporating glycosyl and zwitterionic groups into DES precursor, the resulting glycosyl zwitterionic DESs can be non-covalently crosslinked by POM nanoclusters through synergistic hydrogen bonding and electrostatic interactions, leading to the solidification of DESs. The dense supramolecular networks formed within SPPCs serve as mechanical support and proton-conducting pathways. This gives SPPCs significant adhesive strength, high viscosity, excellent proton conductivity, and high mechanical-conductive decoupling ability. Furthermore, vanadium-substituted POM nanoclusters in SPPCs exhibit an additional pseudocapacitance for flexible supercapacitors, achieving an impressive increase in specific capacitance compared to tungsten-containing POM nanoclusters. This work highlights the immense potential of using functional supramolecular polymers to boost the development of innovative electrolyte materials.