A water cluster (H2O)12 guested coordination polymer as proton conducting solid electrolytes

A coordination polymer with ordered and non-acidic water-cluster guest molecules, [Zn(cis-chdc)(bpp)]·6H2O (denoted as Zn2-(H2O)12, H2chdc = 1,4-cyclohexanedicarboxylic acid; bpp = 1,3-bis(4-pyridyl)propane), which captures a kind of (H2O)12 cluster inside the cavity, is found to be an efficient proton conducting solid electrolyte. Zn2-(H2O)12 has a high conductivity of 0.241 mS·cm−1 at 318 K and 95% RH (relative humidity), which is higher than the other kinds of water-only guested coordination polymers (CPs). The configuration of the water clusters has been described and the role it plays in the process of proton transportation has been investigated preliminarily.