摘要
采用化学法制备纳米β-PbO2对MnO2电极进行掺杂改性。X射线衍射光谱法(XRD)、透射电子显微镜法(TEM)分析表征结果表明,以含Pb2+的偏酸性溶液[Pb(NO3)2水溶液或Pb(Ac)2水溶液]为铅源,以过量的高浓度碱性NaClO溶液为氧化剂,在5~10℃强力搅拌反应2h生成可溶性铅酸盐溶液,再加稀硝酸将溶液pH值调低至7.0左右即可制得粒径30nm左右、晶型完整的β-PbO2粒子。对用纳米β-PbO2掺杂改性的MnO2电极进行放电性能测试的结果表明,将5%~10%的纳米β-PbO2掺入到MnO2中制成的掺杂电极的放电容量较纯MnO2电极可提高60%以上,放电过程电位升高200mV以上。循环伏安测试结果表明,β-PbO2与MnO2的放电产物形成复合产物,改变了反应历程,在一定程度上抑制了电化学惰性物质Mn3O4的生成和积累,从而使MnO2电极的可逆性得到了改善。
The preparation of nano-β-PbO2 and its doping modification to MnO2 electrodes were studied. The preparation procedure was as follows: Pb(NO3)2 or Pb(Ac)2solutions was used as lead source and alkaline NaCIO was used as oxidant. After agitating at 5-10 ℃ for 2 h, followed by adjusting pH to around 7.0, the product of β-PbO2 particles was obtained. XRD and TEM examinations show that the β-PbO2 particles have complete crystal-type and grain size of 30 nm. The modified MnO2 electrodes were fabricated by doping the prepared nanosize /3-PbO2 to MnO2 and their electrochemical properties were studied by constant current discharge and CV testing. The constant current discharge result shows that when 5%--10% β-PbO2 is added, the nanosize β-PbO2 modified MnO2 electrodes provide around 200 mV discharge voltage and 60% discharge capacity higher than that of pure manganese dioxide electrodes. The result of CV indicates that the reaction mechanism is changed through interaction of β-PbO2 and MnO2 so that the formation of electrochemically inactive Mn3O4 is restrained and the reversibility of the MnO2 electrode is improved.
出处
《电源技术》
CAS
CSCD
北大核心
2008年第4期228-232,共5页
Chinese Journal of Power Sources