石墨烯/硫酸铅复合材料的制备及其在铅酸电池中的电化学性能

利用简单的浸渍法制备了石墨烯/硫酸铅复合材料,使得硫酸铅可以直接用作铅酸电池负极材料。该复合材料分别以100 mA·g^-1、200 mA·g^-1和300 mA·g^-1电流密度放电时,平均放电比容量分别可达到110、94和69 mAh·g^-1,而硫酸铅仅为49、5和0.5 mAh·g^-1,显示出复合材料在高倍率充放电下更好的比容量和再接受充电能力。循环伏安测试表明石墨烯的电容效应随扫描速率增大而增强,同时析氢也变得严重,使得复合材料在充放电过程中充电效率比纯硫酸铅低20%。在充放电过程中,石墨烯能够提高硫酸铅1倍以上的放电容量,并将充电电压提高0.1 V。XRD和SEM结果显示硫酸铅均匀分布在石墨烯片层上,没有出现团聚现象。

Synthesis and Characterization of Lead Sulfate/Graphene Nano Sheets Composites as Anode Materials for Lead Acid Battery

Lead sulfate/graphene nano sheets (GNS) composites were fabricated by using a simple impregnation method. The composite was used as a negative active material for lead acid battery. Compared with pure lead sulfate electrodes, the composite electrodes display higher specific capacity and rechargeable performance under high charge and discharge rates. An average discharging specific capacity of PbSO₄/GNS composites reaches 110, 94 and 69 mAh·g^-1 at current density of 100 mA·g^-1, 200 mA·g^-1 and 300 mA·g^-1, respectively. However, the average discharging capacity of PbSO₄ only reaches 49, 5 and 0.5 mAh·g^-1 at the same condition. The electrochemical characteristic of the composites electrode was studied by cyclic voltammetry (CV) and battery tests. The cyclic voltammetry results show that capacitive effect and the hydrogen evolution of graphene nano sheets become more obvious with the increase in scanning rateresulting in 20% lower charging efficiency of PbSO₄/GNS composites compared to lead sulfate. The battery charge-discharge curves confirm that graphene nano sheets improve the charging voltage about 0.1 V and can also help double the capacity of lead sulfate. The XRD and SEM results show that lead sulfate particles are well dispersed on the surface of graphene nano sheets instead of agglomerating.