PMMA/MWCNTs复合膜包覆Mg_3MnNi_2合金电极的电化学性能研究

Electrochemical hydrogen storage properties of Mg_3MnNi_2 electrode coated by PMMA/MWCNTs composite film

采用手工铸膜的方式把PMMA/MWCNTs复合膜包覆在Mg_3MnNi_2电极片表面。利用扫描电子显微镜(SEM)观察分析聚合物包覆后电极片表面形貌以及电极片的截断面,结果表明厚度为20 mm的PMMA/MWCNTs复合膜均匀包覆在Mg_3MnNi_2电极片的表面。恒电流充放电结果表明,经过PMMA/MWCNTs复合膜包覆后,电极片在电解液中的循环稳定性得到较大改善,10个循环的容量保持率从45.0%提高到72.7%。Tafel极化测试结果表明,PMMA/MWCNTs复合膜能够有效提高电极片的抗腐蚀性能。电极动力学测试结果表明PMMA/MWCNTs复合膜包覆降低了电极表面的电荷转移速率,但不影响合金中氢的扩散能力。

Mg3MnNi2 electrode was coated by PMMA/MWCNTs through manual casting films.Scanning electron microscopy(SEM)was used to observe the surface morphology of the prepared electrodes and the fractured surface of the coated electrode.The results show that PMMA/MWCNTs composite film of about 20μm of the thickness is successfully coated on the surface of Mg3MnNi2 electrode.The galvanostatic charge-discharge test show that the discharge capacity retention rate at the tenth cycle(S10)increases from 45.0%to 72.7%,indicating that the PMMA/MWCNTs composite film can significantly improve the cycling stability.The results of Tafel polarization test indicate that the PMMA/MWCNTs composite film can enhance the anti-corrosion ability.Potentiostatic discharge,linear polarization and EIS were tested to investigate the kinetic properties of the prepared electrodes and the results show that the PMMA/MWCNTs composite film has no effect on the diffusion of hydrogen,and the hydrogen diffusion ability in the alloy is not affected.