CO₂资源化转化纳米碳材料对硫酸盐化铅盘电极的活化性能研究
Activation Effect of Nano-Carbon Derived from CO₂ on Lead Electrode in Sulfuric Aqueous Solution

摘要 负极板硫酸盐化是铅酸蓄电池早期容量下降、提前失效的主要原因之一. 利用碳材料制备活化剂加入电池电解液中，可以有效减少或修复不可逆硫酸盐化现象. 本文研究了一种新型高导电纳米碳材料—CO2高温熔盐电化学转化制备碳粉，对硫酸盐化铅盘电极的活化效果，结果表明，新型碳粉对于铅盘电极电量和电流效率的提升效果比乙炔黑和碳纳米管更显著，在一定浓度范围内对析氢无影响，碳粉的存在提高了电极活性物质间的导电性，并可在其表面吸附富集铅离子和提供还原位点，从而促进硫酸铅的溶解、抑制大颗粒硫酸盐晶体的产生，表明CO2高温熔盐资源化转化制备的碳粉作为一种新的铅蓄电池碳材料活化剂具有较好的发展潜力.
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