| MH-Ni battery is the most promising power used in EV and HEV in the futureyears because of its advantages such as high special capacity, high special power,cleanliness and no pollution. So far, the manufacture technology of small singleMH-Ni battery has been fledged, but power typical MH-Ni battery package still hasmany problems such as bad over-discharge resist ability, high-rate discharge abilityand high internal-pressure that need to be solved soon. This paper tries out to solvethese problems by adding several kinds of additive to negative electrode. Negative electrode was made with Co or Co oxide additive, then it was executedcharge-discharge test, polarization test and Cyclic voltammograms test in threeelectrode system. The results are: after adding Co or Co oxide additive, anotherdischarge plateau was found at –772mV(VS. Hg/HgO) because of Co oxidizationreaction, so that MH-Ni battery package improved the over-discharge resist ability;Co added in negative electrode can improve its electronic catalysis, so that thedischarge special capacity was improved from 274.5mAh/g to 307.2mAh/g, but CoOadded in negative had no function on negative electrode; Co added in negativeelectrode can improve its high-rate ability, but CoO could not do so; the exchangecurrent density of the negative without additives, with Co additive and with CoO was77mA/g, 321mA/g and 81mA/g, which was known by polarization test, thatillustrated adding Co can make the negative electrode reaction been more active thanCoO; CV test showed that the negative electrode charge reaction took place at–1.0V(VS. Hg/HgO) and discharge reaction took place at –0.87 V(VS. Hg/HgO);during charging hydrogen atom was adsorbed and adsorbed hydrogen was transferredabsorbed hydrogen then it diffused into alloys. The Perovskite-type oxygen reduce catalyst was synthesized by sol-gel methodand was added in the negative electrodes, then batteries were made with them. Thenegative electrodes were executed polarization test in three electrodes system and thebatteries were executed internal-pressure test and temperature test during charging.The results were: the special surface dimension of the catalyst was improved byaddition of Co, while catalyst was synthesized, but after the quantity of Co reachsome proper value, it will do inversely; the electrocatalytic activity of LaNi1-yCoyO3(y=0～1.0) first increase and then decreased with the increase of Co; theinternal-pressure of the batteries with Perovskite-type oxygen reduce catalyst waslower than that without catalyst during charging, and when the DOC was over 100%,the difference between them was larger; the temperature of the batteries with catalystwas increased more slowly than that without catalyst because of their low polarizationthermal utility; the cycle life of the batteries with catalyst can be improved becausethe catalyst make alloys been corrupted fewer; and the catalyst being added tonegative electrode have few influence on discharge capacity and high rate dischargeability of the batteries. |
