稀土添加剂对铅电极气体析出行为的影响

Effect of rare earth additive on gassing behaviour of lead electrode

研究了活性物质中稀土添加剂对铅酸蓄电池正、负电极在充电时的气体析出行为、活性物质利用率及化成效率等方面的影响。对含稀土添加剂的铅电极在恒压 4h连续充电条件下测量其气体析出量 ,并分析了化成时电极中PbO2 含量的变化。结果表明 ,在 2 .40V连续恒压充电 4h过程中 ,含有稀土添加剂的正极气体析出量为 3 .5mL。不含稀土添加剂同样条件下的结果为 4.8mL。在更高的恒压充电条件下 ,其差别更加明显 (恒压 2 .5 0V时含有稀土添加剂为 10 .2mL ,不含稀土添加剂为 15mL)。含有稀土添加剂的负极在 2 .40V恒压充电 4h的气体析出量为 10 .8mL。不含稀土添加剂的负极同样条件下为 5mL。PbO2 含量测定表明 ,含有稀土添加剂的正极化成 3 2h即可达到PbO2 含量 85 %以上 ,不含稀土添加剂的电极则在化成 65h时达到同样的数据。活性物质中加入稀土添加剂可明显降低正极充电时氧气析出量 ,并对提高正极活性物质利用率有一定作用 ,但在负极中可使氢气析出量增加 。

The effects of rare earth additives in active materials on gassing behavior, utilization of active materials and formation efficiency during charge were studied. The gassing volume of lead electrode with rare earth additives was determined during 4 h continuous charge, and the change of PbO 2 content in electrode during formation was analyzed. The results show that during 4 h continuous charge at 2.4 V constant voltage, the gassing volume of the positive with rare earth additives is 3.5 mL while that of the lead electrode without additives is 4 8 mL.When the constant voltage is increased to 2.5 V, the difference of gassing volume is significant (10.2 mL of that with additives compared with 15 mL of that without additives).During 4 h continuous charge at 2 4 V constant voltage, the gassing volume of the negative with rare earth additives is 10.8 mL while that of the lead electrode without additives is 5 mL. The determination result of PbO 2 content shows that PbO 2 content in the positive with rare earth additives is 85% after 32 h formation, while the positive without rare earth additives needs 64 h formation to obtain the same PbO 2 content. Therefore, adding rare earth additives in positive active material can decrease O 2 gassing volume significantly during charge and improve the utilization of positive active material. However, adding rare earth additives in negative active material causes H 2 gassing volume increase, which is adverse to sealed lead acid battery.