Effect of surface modification of metal hydride electrode
on performance of MH/Ni batteries
on performance of MH/Ni batteries
(School of Chemical Engineering and Environmental Science, Beijing Institute of Technology, Beijing 100081, China;
National Development Center of Hi-Tech Green Materials, Beijing 100081, China)
National Development Center of Hi-Tech Green Materials, Beijing 100081, China)
Abstract: A novel method was applied to the surface modification of the metal hydride(MH) electrode of MH/Ni batteries. Both sides of the electrode were plated with a thin silver film about 0.1μm thick using vacuum evaporation plating technology, and the effect of the electrode on the performance of MH/Ni batteries was examined. It is found that the surface modification can enhance the electrode conductivity and decrease the battery ohimic resistance. After surface modification, the discharge capacity at 5C (7.5A) is increased by 212 mA∙h and the discharge voltage is increased by 0.11 V, the resistance of the batteries is also decreased by 32%. The batteries with modified electrode exhibit satisfactory durability. The remaining capacity of the modified batteries is 89% of the initial capacity even after 500 cycles. The inner pressure of the batteries during overcharging is lowered and the charging efficiency of the batteries is improved.
Key words: surface modification; vacuum evaporation plating technology; electrode; MH/Ni batteries