Effects Of Electrolyte Additives And Alloy Compositions On The Electrochemical Behaviors Of The Grid Of Lead-acid Battery

Lead acid battery is an important chemical power source with a wide range of applications in the national economy and our daily life. It’s research has made some progress in all aspects in recent years. As the connect bridge of the positive and negative of the lead acid battery system, the electrolytes not only conduct the current, but also take part in the electrode reactions, playing a significant impact on the battery performance. For a long time, a lot of researches have been taken at home and abroad on the performance of the lead acid battery by adding some additives into the sulfuric acid electrolyte. By using the electrolyte additives, it has the advantages of not changing the production process of the lead acid battery industry, low additional cost, good effect, easy to promotion, etc. Therefore, choosing a suitable electrolyte additive has been an important method to enhance the lead acid batteries capacitor and improve their deep cycle charge-discharge performance.In this thesis, by adding different concentrations of HNO3and Na2SO4into the H2SO4solution to change the electrolyte composition of the experiment system, a comparative study about the effects of electrolyte additives on the electrochemical behaviors of the Pb, Pb-Ca and Pb-Sb series of alloy electrodes which are most commonly used as the lead acid battery plate materials is carried out with the electrochemical techniques such as cyclic voltammetry, linear sweep voltammetry and electrochemical impedance.By the further comparative study of the Pb-based alloys in electrolytes with different additives in terms of the hydrogen and oxygen evolution over potential and the corrosion resistance, we can provide a theoretical basis in order to increase the cycle life and capacitors of the lead acid battery system as well as improve it’s deep cycle charge-discharge performance.The main work is as follows:1. Electrochemical reactions of Pb electrode in H2SO4with HNO3, Na2SO4additivesThe electrochemical methods of Linear Sweep Voltammetry (LSV) and Electrochemical Impedance (EIS) are used to compare the hydrogen and oxygen evolution reaction and anodic oxidation reaction of Pb electrode in3.5M H2SO4,3.5M H2SO4+0.05M HNO3and3.5M H2SO4+0.05M Na2SO4. It is found that H2SO4with Na2SO4additive solution can inhibit the evolution of H2and O2on the Pb electrode, and the inhibition of the lower Na2SO4concentration is more obvious. And it can inhibit the formation of PbO which has a high impedance. The effect of the PbO2film formed on the Pb electrode in Na2SO4+H2SO4is also compared by the additive concentration, oxidation time and oxidation potential.2. Redox behavior of the Pb-Ca and Pb-Sb electrode in H2SO4with HNO3, Na2SO4additivesThrough the study of the redox process as well as the hydrogen and oxygen evolution of the Pb-Ca and Pb-Sb electrode in different additive solutions, it is found that high concentration of HNO3and low concentration of Na2SO4additives can inhibit the formation of the PbO2film on the Pb-Ca electrode. And the hydrogen and oxygen evolution reaction on the Pb-Sb electrode are inhibited more obviously, which plays a positive role in the maintenance-free performance of the lead acid battery.3. Corrosion behavior of the series of Pb-Ca electrode in3.5M H2SO4+O.O5M Na2SO4Under the same conditions, the current of hydrogen evolution on Pb-Ca-Sn-Al is the minimum after the research of the reactions on Pb-Ca, Pb-Ca-Sn and Pb-Ca-Sn-Al electrodes, which is good for the maintenance-free performance of the battery. On the other hand, the study shows that Pb-Ca-Sn is tend to generate loose PbSO4film, the PbSO4film formed on Pb-Ca-Sn-Al is relatively compact, and the PbO film resistor of Pb-Ca is the biggest.4. Anodic polarization behavior of the series of Pb-Sb electrode in3.5M H2SO4+0.05M Na2SO4The study of the two kinds of Pb-Sb and Pb-Sb-Sn electrodes in3.5M H2SO4+0.05M Na2SO4demonstrates that the content of Sn in Pb-Sb continued to inhibit the formation of the oxygen, it slows down the evolution of oxygen of the battery to some extent. Besides, the Pb-Sb-Sn electrode can be a good inhibition for the growth of the anodic oxide film on the electrode, therefore, it can increase the conductivity of the corrosion film, reduce the loss of the battery current, improve the corrosion resistance of the grid and help to curb the self-discharge of the battery.