摘要
把羟丙基甲基纤维素(HPMC)与聚四氟乙烯(PTFE)联用、羧甲基纤维素(CMC)与PTFE联用和单独使用HPMC三种粘结剂使用方法进行比较,并对它们的添加量做了研究。通过对不同状态的充放电性能的比较,并结合扫描电子显微镜(SEM)和能量散射光谱(EDS)对极片表面进行分析,单独使用HPMC作为粘结剂的电极有较好的充放电性能,且随着添加量的增加,电极的充放电性能下降;使用HPMC+PTFE作为粘结剂的电极容量有所提高,但是大电流和高温放电性能不如单独使用HPMC作为粘结剂的极片,随着PTFE添加量的增加电极的容量减少。通过对充放电以后极片的SEM和EDS分析,我们发现单独添加HPMC和CMC+PTFE作为粘结剂的极片表面掉粉现象严重,添加HPMC+PTEF的极片表面形成了一层致密的三维网状结构,它能够抑制充放电过程中极板的膨胀,并且可以减少活性物质的脱落,提高电极的循环寿命。经过对比发现添加0.4%HPMC+0.4%PTFE时电极的综合性能最好。
CMC＋PTFE, HPMC and HPMC＋PTFE were used as binders and the effects of the binders on the positive electrodes properties of Ni-MH were investigated by the electrochemical measurement, SEM and EDS methods, individually. For the single added HPMC electrodes, the discharge capacity are increased, the high rate discharge and high temperature performance are improved compared to the binder with the composition of CMC＋PTFE. With the increase of the HPMC concentration, the discharge capacity increases, and the addition concentration has little influence on the high rate charge-discharge performance. For the binder as a mixture of HPMC＋ PTFE, all the sample have the higher discharge capacity, lower high rate and high temperature charge-discharge efficiencies as well as lower medium value voltage than those of the single addition of HPMC. It can be seen from SEM that a film is formed on the surface of positive electrodes and no nickel hydroxide powders detach from the surface after the charge-discharge test, which indicates that the addition of PTFE to the HPMC can greatly inhibit the nickel hydroxide powders pull-off from the surface of the electrodes, which can benefit to the service life of the Ni-MH battery. Finally, the conclusion was given that the sample using HPMC （0.4%）＋PTFE （0.4%） as binder exhibited excellent electrochemical properties.
出处
《电源技术》
CAS
CSCD
北大核心
2009年第2期134-137,共4页
Chinese Journal of Power Sources
