掺杂金属氧化物贮氢电极的电化学性能

研究了掺杂金属氧化物Fe3O4和Cr2O3贮氢电极MmNi3.5Mn0.4Co0.7Al 0.4(Mm: 混合稀土)的电化学性能.结果表明,Fe3O4和Cr2O3的掺杂均使贮氢电极的放电容量增大和充电效率提高,且活化性能得到改善,活化次数减少到3～5次.Cr2O3的掺杂可使贮氢电极的放电过电位减少3.0 mV、快速放电能力(放电电流密度为500 mA*g-1)提高8.1%,同时改善了电极的循环稳定性;在同样条件下,Fe3O4的掺杂使电极过电位增大50.2 mV、快速放电能力降低11.6%,并导致电极的电荷保持能力下降.从MmNi3.5Mn0.4Co0.7Al 0.4电极的综合性能考虑,Cr2O3的掺杂对改善贮氢电极的电化学性能是有利的.

Electrochemical Properties of Hydrogen Storage Electrode Modified with Metal Oxides

The performances of the hydrogen storage electrode MmNi3.5Mn0.4Co0.7Al 0.4(Mm: mischmetal) modified by mixing it with Fe3O4 and Cr2O3 were studied. The discharge capacity, charge efficiency of the modified electrodes were increased, activation numbers of the electrodes were reduced to 3～5 cycle. The discharge overpotential of modified negative electrodes were decreased 3.0 mV for Cr2O3 and heightened 50.2 mV for Fe3O4. The high-rate dischargeability of the modified electrode was enhanced 8.1% for Cr2O3 and reduced 11.6% for Fe3O4 at 500 mA*g-1, respectively. The cycling stability of the modified negative electrode was improved by addition of Cr2O3. The wicked charge retention of the electrode containing Fe3O4 was measured. Considering the global effect of metal oxides addition on the overall performance of MmNi3.5Mn0.4Co0.7Al 0.4 alloy electrode, Cr2O3 was an appropriate additive.