Surface modification for La1-xCex(NiCoMnAl)5hydride electrode by
hot charging in potassium borohydride solution①
hot charging in potassium borohydride solution①
(1. Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110015, P.R.China;
2. College of Materials and Metallurgy, Northeastern University, Shenyang 110006, P.R.China)
2. College of Materials and Metallurgy, Northeastern University, Shenyang 110006, P.R.China)
Abstract: The La1-xCex(NiCoMnAl)5alloy electrodes were treated by hot charging in alkaline aqueous solution containing KBH4. The activation behavior, hydrogen diffusion coefficient and maximum discharging capacity, high rate discharging capability of alloy electrodes were tested. The surface morphology and element content were observed by scanning electron microscope. The results show that the alloy electrode is fully activated after the second charging-discharging cycle and has a high rate discharging capability of 85% at 900mA/g. The surface has a lot of micro-cracks and hydrogen diffusion coefficient is about (2~3)×10-9cm2/s . Therefore, this method can markedly improve activation behavior and high rate charging capacity of the alloy electrode. The mechanism of this surface modification of the alloy electrode is also discussed.
Key words: hydrogen storage alloy; surface modification; KBH4alkaline aqueous solution; hot charging treatment