高氯酸掺杂聚苯胺复合阴极的制备及性能研究

Preparation and Properties of Perchloric Acid Doped Polyaniline Composite Cathode

目的为提高聚苯胺海水电池正极的导电性和放电性能,研究各种制备工艺条件对电极性能的影响。方法采用电化学的方法,以石墨纸为载体,在高氯酸体系中制备聚苯胺(PANI)/二氧化锰(MnO_(2))/氧化石墨烯(GO)复合电极,研究复合电极制备的最优条件。采用X射线衍射仪、红外光谱仪和扫描电镜表征复合电极,采用交流阻抗法、循环伏安法和极化曲线研究电极的电化学性能。结果石墨纸在室温下经30 mA/cm^(2)的电流密度氧化60 min后,在磺基水杨酸(SSA)质量浓度为15 g/L,硫酸锰浓度为0.2 mol/L的苯胺-高氯酸溶液里以电流密度18 mA/cm^(2)聚合20 min,可制备出较优的PMGO复合电极,它与镁合金组成海水电池,以200 mA/g恒流放电至1 V,其比能量可达600 W·h/kg。PMGO复合电极的表面微观形貌是由纳米线组成的三维立体网状结构,聚苯胺与二氧化锰成功复合到氧化石墨烯表面。结论高氯酸体系掺杂的聚苯胺导电性增强,氧化使石墨纸表面形成大量的氧化石墨烯,为苯胺聚合、复合提供大量活性点,复合后电极比表面积增大,与电解液充分接触,使电极活性物质利用率提高,并降低了电极的极化,电化学性能也远优于AgCl电极。

The work aims to study the effect of various preparation technologies on properties of electrode so as to improve the conductivity and discharge property of positive electrode of polyaniline seawater battery.The polyaniline(PANI)/manganese dioxide(MnO_(2))/graphene oxide(GO)composite electrode was synthesized by electrochemical method on graphite paper and the optimum synthesis condition of the composite electrode was studied.The XRD,SEM and FT-IR were used to characterize the composite electrode.The electrochemical property of the composite electrode was measured by the AC impedance method,cyclic voltammetry and polarization curve.After the graphite paper was oxidized at room temperature for 60 minutes under the oxidation current density of 30 mA/cm^(2),the optimal PMGO composite electrode was synthesized at the polymerization current density of 18 mA/cm^(2) in HClO_(4)-aniline solution containing sulfosalicylic acid(SSA)of 15 g/L and 0.2 mol/L MnSO_(4) for 20 minutes of polymerization.The seawater battery composed of composite electrode and magnesium alloy discharged to 1 V at a constant current of 200 mA/g,and the specific energy reached 600 W·h/kg.The surface microstructure of the PMGO composite electrode showed a complex 3D network structure constructed by nanowires on graphite paper.Polyaniline and manganese dioxide were successfully compounded on the surface of graphene oxide.The conductivity of polyaniline doped with perchloric acid has been enhanced.A large amount of GO is formed on the surface of graphite paper by oxidation,providing numerous active sites for the polymerization of PANI.Thus,specific surface area of electrode prepared increases and fully contacts electrolyte,which improves the utilization of active material and reduces the composite electrode polarization.The electrochemical property of PMGO is much better than that of AgCl electrode.