Solvent-free mechanochemical synthesis of organic proton conducting salts incorporating imidazole and dicarboxylic acids

Solventless mechanochemical synthesis by manual grinding was applied to grow organic proton conducting salts, imidazole-succinic acid (C3H4N2-HOOC(CH2)2COOH) and imidazole-glutaric acid (C3H4N2-HOOC(CH2)3COOH). This synthesis method induces crystallization and provides the phase-pure compounds. The compounds exhibit different electric conducting behavior and activation energies Ea compared with the reported single crystals obtained from the solution method. The difference in conducting property can be related to intrinsic defects and structural disorder introduced by mechanochemical grinding, indicating that the mechanochemical method bears strong capability for tuning conductivities. Moreover, complete deuteration of the organic salts is achieved by the method. The mechanochemical synthesis of organic salts also holds high potential for the actual industrialized large-scale production.