负极添加剂对镍氢电池性能的影响

Effect of Anode Additives on Performance of Nickel Metal Hydride Batteries

以市售A_(2)B_(7)型La-Mg-Ni系储氢合金作为负极材料,并分别以Y_(2)O_(3)、La_(2)O_(3)、ZnO和MgO作为添加剂制作AA1500型镍氢电池,并对其放电容量、充电态内阻、自放电、循环寿命和过充性能进行测试与分析。结果表明:添加Y_(2)O_(3)和La_(2)O_(3)的电池在0.2 C倍率下的放电容量与未添加电池基本一致,而以MgO和ZnO作为添加剂制作的电池容量比未添加的分别低7.2 mAh和17.1 mAh;不同负极添加剂的加入均导致电池的内阻升高;但加入添加剂制作的电池自放电性能均有不同程度的提高,添加MgO制作的电池55℃储存7 d后荷电保持率最好,达到80.1%;添加Y_(2)O_(3)和La_(2)O_(3)与未添加制作的电池具有较好的耐过充性能;添加Y_(2)O_(3)制作的电池的循环寿命得到明显提高,循环200次后容量保持率提高至86.19%。

AA1500 type nickel metal hydride batteries were prepared by using A_(2)B_(7) type La-Mg-Ni hydrogen storage alloy as anode material and Y_(2)O_(3),La_(2)O_(3),ZnO,MgO were added as additives.The discharge capacity,internal resistance of charging state,self-discharge,cycle life and overcharge performance of the battery were tested and analyzed.The results show that the discharge capacity of the batteries with Y_(2)O_(3) and La_(2)O_(3) at 0.2 C is almost the same as that of the batteries without addition,while the capacity of batteries with MgO and ZnO as additives is 7.2 mAh and 17.1 mAh respectively lower than that without addition.The addition of negative electrode additive increases the internal resistance of the battery in different degrees.However,the self-discharge performance of the battery made by adding additives was improved to varying degrees.The battery made by adding MgO has a best charge retention rate which is 80.1%after being stored at 55℃for 7 days.The battery with added Y_(2)O_(3) and La_(2)O_(3) and without added has better overcharge resistance;cycle life of the battery made by adding Y_(2)O_(3) is obviously improved,and the capacity retention rate is increased to 86.19%after 200 cycles.