关键词: 铅酸蓄电池, 硫酸盐化, 活化, 碳材料, 二氧化碳资源化

Abstract:

Serious sulfation of the negative plate is one of the most popular reasons of the early failure of lead-acid battery. Addition of nano-carbon was proved to be effective for recovering the sulfated electrode and the property of the carbon material always plays an important role. In this work, a new kind of nano-carbon material with high electrical conductivity and good adsorption capability for heavy metal cations, which is electrochemically prepared from CO₂ in molten carbonates, was tested as activation additive for the sulfated lead electrode by cyclic voltammetry and SEM measurements. The results showed that the as-prepared carbon can effectively enhance the activity of the sulphated lead electrode, super to acid-treated acetylene black and carbon nanotubes at the same concentration. No serious hydrogen evolution took place when the concentration of carbon was not higher than 1 g•L^-1. It was also found that its activation effect is strongly dependent of its concentration in the solution. Based on the test results and SEM analysis, a possible activation mechanism of the carbon was proposed. The adsorption of the carbon powder at the surface and interface of the PbSO₄ particles can enhance the conductivity of the electrode, promote the dissolution of the sulfate crystals through its capacity of the absorption of plumbous ions and provide more active site for reduction and oxidation. However, too much adsorbed carbon will block the pathway of ions transportation within the porous electrode. The results suggest that the carbon powder derived from CO₂ could be a new kind of activator for the electrode of lead acid battery.