泡沫镍@氮掺杂碳/二氧化锰一体化电极的制备及其在直接甲醇燃料电池中的应用

Preparation of Ni-foam@Nitrogen doped carbon/MnO_(2) integrated electrode and its application in direct methanol fuel cell

通过水热法和沉淀法两种方法制备出了泡沫镍@氮掺杂碳/二氧化锰一体化电极(泡沫镍@NC/MnO_(2)),使用XRD、XPS、SEM对材料的组成及微观形貌进行了分析.对比了两种方法制备的泡沫镍@NC/MnO_(2)作为直接甲醇燃料电池(DMFC)阴极、PtRu/C作为阳极催化剂、聚合物纤维膜作为电解质膜的单电池的放电性能.室温性能测试表明,两种方法制备的一体化电极的放电性能比较接近,在10 mA·cm^(-2)电流密度下可以稳定放电18 h,没有明显的衰减.在60℃高温测试中,采用沉淀法得到的泡沫镍@NC/MnO2一体化电极组装电池,其最大功率密度为9.14 mW·cm^(-2),而采用水热法得到的泡沫镍@NC/MnO_(2)一体化电极组装电池,其最大功率密度为16.67 mW·cm^(-2).水热法得到的泡沫镍@NC/MnO2电极具有更好的氧还原催化性能,其主要原因是水热合成在缺氧条件下完成,使得制备的催化剂中含有较多的氧空位,可以加速氧气的吸附以及电荷传输.

Ni-foam@Nitrogen doped carbon/MnO_(2)(Ni-foam@NC/MnO_(2))integrated electrode was synthesized by hydrothermal method and precipitation method,respectively.The phase structure and micro morphology of the composite materials were analyzed by XRD,XPS and SEM.In this work,the direct methanol fuel cell(DMFC)was assembled by Ni-foam@NC/MnO_(2) as cathode,PtRu/C as the anode catalyst,and polymer fiber membrane as the electrolyte membrane.The integrated electrodes synthesized by the two methods showed relatively closed discharge performances at room temperature.The DMFCs could discharge stably for 18 hours at a current density of 10 mA·cm^(-2) without significant attenuation.However,in the 60℃tests,the maximum power density of the foamed Ni-foam@NC/MnO_(2) integrated electrode synthesized by hydrothermal method was 16.67 mW·cm^(-2),while the maximum power density of the electrode synthesized by precipitation method was 9.14 mW·cm^(-2).This is because the decrease of oxygen concentration in hydrothermal synthesis promoted the presence of more oxygen vacancies,and accelerated the oxygen adsorption and electron transfer.