# Renewal of Lead Battery Electrodes Using a Plasma--Chemical Processing Method
## 3 The Results and Discussion  
The surface morphology of the battery's lead electrodes was analyzed using a scanning electron microscope. The studies of the surface morphology of Pb electrodes are presented in Figure 1. In Figure 1a, we can see the surface morphology of the new (unused) Pb electrode of the battery. As can be seen in this case, the surface is uneven, composed of irregularly shaped microstructures. In this case, the dimensions of the microstructures vary in a wide range of 10-50 \(\upmu\)m. Figure 1b shows the surface morphology of the Pb electrode when the battery was charged/discharged for 500 cycles, which is considered completely worn out. In this case, the visible surface is more uniform than the electrodes of a new battery. This is because chemical reactions occur on the surface of the electrodes during the charging/discharging process. At the same time, the process of surface etching takes place, during which, part of the microstructures are destroyed, or their geometric dimensions are reduced. In the picture Figure 1c, we see the surface of the Pb electrodes of a worn battery that has been exposed to an Ar gas plasma [1; 3]. As SEM analysis shows, the surface morphology in this case is similar to Figure 1b. This is because the Ar gas is inert, and chemical etching does not take place when the surface is exposed to it (the surface is only bombarded with Ar ions and molecules), so it is unlikely that new microstructures will form. However, the Ar gas exposure process can be useful to renew the structure of Pb electrodes in batteries. Figure 1d shows the surface of a Pb electrode after being etched in O\({}_{2}\) plasma. In this case, the visible surface is uneven and consists of microstructures of fine structure and irregular shape. Since, in this case, the surface etching with reactive gas takes place, some microstructures are destroyed, but, at the same time, new microstructures are formed on the surface of the Pb electrode. The distribution of elements on the surface of Pb electrodes was studied using the EDS method. Elemental composition studies are presented in Figure 2. The investigations of the elemental composition of the Pb electrode of the new battery are presented in Figure 2a. As we can see in this case, the predominant elements are Pb, Si, C, O, and Al. Observing only the color difference in the picture, it is difficult to assess which element has the largest amount. The elements Al and C are likely to appear during the electrode manufacturing process, while S and O are likely to be a component of the battery electrolyte, with small amounts deposited on the surface of the electrodes. Figure 2b shows the elemental composition of the surface when the battery is considered worn out. As can be seen, the predominant elements are the same as in the case of a new battery. It can also be noted that Ca, Fe, Na, and Mg elements are visible in the case of a worn-out battery, but as further EDS analysis showed, their amount is negligible, probably due to measurement error. The percentage composition of elements on the surface of Pb electrodes was measured using the EDS method. The results of the percentage elemental composition studies are presented in Table 1.  
Analyzing the results of the EDS measurements, it can be observed that, in the case of a new battery, the largest content of the electrode material is lead--about 80%, while the remaining elements are oxygen, carbon, and sulfur, the percentages of which are 11%, 5% and 2.6%, respectively. In the case of a worn out battery, and the percentage of Pb is about 68.2%, while the percentage of oxygen is about 21%.