聚苯胺/膨胀石墨电极的制备及其用于聚合物半电池的研究

Fabrication of Polyaniline/Expanded Graphite Electrode and Its Application in Polymer Half-cell

以膨胀石墨作为基底电极,采用恒电位法合成了聚苯胺(PAn),并探讨了在膨胀石墨基底电极上电聚合生成PAn的电化学条件.结果表明:聚合电位为0.8 V,苯胺和硫酸的浓度分别为0.2和0.3 mol/L的条件下电聚合得到的PAn具有最佳的电化学活性.分别以PAn/膨胀石墨和金属Mg为工作电极,铂片为辅助电极,饱和甘汞电极为参比电极组成三电极体系,测定PAn/膨胀石墨和Mg在0.1 mol/L的NaNO2,MgCl2,Mg(NO3)2及磷酸盐缓冲液(PBS)等不同电解质溶液中的极化曲线,实验结果表明电解液的种类对PAn的稳定性影响不大,而Mg在0.1 mol/L NaNO2溶液中的稳定性最高.以PAn/膨胀石墨作为阴极,金属Mg为阳极,0.1 mol/L NaNO2为电解液组装成Mg│NaNO2│PAn电池,并考察了基于该聚合物电极的电池在电流密度为30 mA g-1时的恒电流放电行为.相比于其它电解液,该电池在0.1 mol/L NaNO2电解液中具有较高的开路电位(1.84 V)和放电比容量(0.19 Ah g-1).

Polyaniline（PAn） films were deposited on an expanded graphite electrode by potentiostatic method.The electrochemical synthesis conditions of PAn were discussed in detail in this paper.The results showed that PAn with high electrochemical activity was obtained by electropolymerization of aniline in a solution containing 0.2 mol/L aniline and 0.3 mol/L sulfuric acid at 0.8 V.A three-electrode system composed of PAn/expanded graphite or magnesium which served as the working electrode,platinum sheet as the counter electrode and saturated calomel electrode（SCE） as the reference electrode was used for testing of the polarization curves of PAn and magnesium in 0.1 mol/L sodium nitrite,magnesium chloride,magnesium nitrate,zinc nitrate and phosphate buffer.The results indicated that the type of electrolyte had little effect on the stability of PAn,however,magnesium presented the best stability in 0.1 mol/L sodium nitrite.Mg│NaNO2│PAn battery was fabricated in which PAn and magnesium were taken as cathode and anode,respectively.This battery was discharged by a galvanostatic method,and the current density was set as 30 mAog-1 in the discharge process.Compared with other electrolytes,this battery showed higher open circuit potential and specific discharge capacity in 0.1 mol/L NaNO2.