不同活性炭对锌溴液流电池正极性能的影响

Influence of different active carbons on performance of positive electrode in Zn-Bromine flow battery

选取了椰壳类、生物质类及酚醛树脂类3种不同的活性炭,以导电塑料为基体,通过热压工艺制备了表面涂层。采用比表面积测试法(BET)及气体吸附法-密度函数理论(DFT)测试并计算了不同活性炭的比表面积及孔径分布;在扫描电镜下(SEM)观察了不同涂层的表面形貌,通过循环伏安曲线(CV)分析,线性极化曲线(LSV)分析及电化学阻抗谱(EIS)分析等一系列电化学方法,得到了涂层的比电容、峰电流、极化过电位及反应电阻等电化学参数,研究了不同活性炭涂层作为锌溴液流电池正极材料其涂层结构、比表面积对其电化学性能的影响。结果表明:生物质类活性炭涂层较椰壳和酚醛树脂类涂层具有更大的比表面积,酚醛树脂类活性炭制备的涂层较椰壳及生物质类活性炭具有更小的反应电阻,综合来看,生物质类活性炭涂层表现出更优的电化学活性。

Three different types of active carbons including coconut shell, biomass and phenolic resin were used as raw materials to prepare the surface coating on the substrate of conductive plastics by hot pressing. The specific surface areas and pore diameter distributions of the different active carbons were tested and calculated using BET and DFT methods. The surface morphology of the different coatings was observed by scanning electron microscopy （SEM） , and the electrochemical parameters in ZnBr2 electrolytes were studied by CV, LSV and EIS methods, and the relationships between properties of the different active carbons and the electrochemical performances as the positive el.corrode in Zn-Br flow battery were investigated. The results show that the coating with biomass active carbon has a higher specific surface area than that of others and the coating with phenolic resin active carbon has the smallest reactive resistance. In general, the biomass active carbon coating shows the best electrochemical activity among the three kinds of coatings.