Proton-conducting materials are a key component of proton exchange membrane fuel cells (PEMFCs) and the advantage of clear structural information in crystal materials offers a pathway for the investigation of the proton-conducting mechanism and pathway. In this work, a new Cd²⁺ coordination polymer material (compound 1) with the formula {[Cd₃(bipy)₃(H₂O)₄][Fe(CN)₆]₂·2H₂O·2(bipy)}_n was successfully synthesized by a solution diffusion method and its proton conduction ability was further determined. Crystal structure analysis confirms the coordination of [Fe(CN)₆]^3–, 4,4′-bipyridine, and H₂O molecules to Cd²⁺ in the three dimensional structure of compound 1. Also, we confirmed that compound 1 of 500–800 nm particle size could be synthesized on a large scale by a facile stirring method. Proton-conductivity analyses revealed that compound 1 shows a water-mediated proton conduction behaviour because the conductivity increased apparently with the increase of relative humidity. Further investigation shows that the highest proton-conductivity of 8.36 × 10⁻⁴ S cm⁻¹ was observed at 60°C and 95 % relative humidity, and the mechanism analysis suggests a Vehicle mechanism exists in the proton conduction process of compound 1.

质子传导材料是质子交换膜燃料电池（PEMFC）的关键组成部分，晶体材料中清晰的结构信息的优势为研究质子传导机理和途径提供了一条途径。在这项工作中，一种新型的Cd ²⁺配位聚合物材料（化合物1）具有式{[Cd ₃（bipy）₃（H ₂ O）₄ ] [Fe（CN）₆ ] ₂ ·2H ₂ O·2（bipy ）} _n通过溶液扩散法成功合成，并进一步确定了其质子传导能力。晶体结构分析证实了[Fe（CN）₆] ^3-，4,4'-联吡啶，和H ₂水分子对Cd ²⁺在化合物的三维结构1。此外，我们证实，可以通过简便的搅拌方法大规模合成500-800 nm粒径的化合物1。质子传导性分析表明，化合物1显示出水介导的质子传导行为，因为电导率随相对湿度的增加而明显增加。进一步的研究表明，最高的质子电导率为8.36×10 ^-4 S cm ^-1在60°C和95％相对湿度下观察到碳氢化合物，其机理分析表明，化合物1的质子传导过程中存在媒介物机理。