AB5-BASED HYDROGEN STORAGE ALLOY, ELECTRODE FOR NICKEL-METAL HYDRIDE BATTERY, SECONDARY BATTERY AND PREPARATION METHOD FOR HYDROGEN STORAGE ALLOY THEREOF

摘要

The present invention relates to a hydrogen storage alloy, an electrode for a nickel-metal hydride battery, a secondary battery and a preparation method for a hydrogen storage alloy thereof. The chemical composition of the hydrogen storage alloy thereof is represented by the general formula La_{(3.0 - 3.2)x}Ce_xZr_ySm_{(1-(4.0 - 4.2)x-y)}Ni_zCo_uMn_vAl_w, in which x, y, z, u, v, and w are molar ratios, and 0.14≤x≤0.17; 0.02≤y≤0.03; 4.60≤z+u+v+w≤5.33; 0.10≤u≤0.20; 0.25≤v≤0.30; 0.30≤w≤0.40. The overcharge performance of the electrode material is satisfied by fixing the ratio of lanthanum (La) to cerium (Ce) to be 3.0-3.2; a large amount of metal samarium (Sm) element is substituted on the A side, namely, the Sm atom ratio accounts for 25.6-42% of the A side, so as to overcome the problem of life reduction caused by low cobalt (Co); the equilibrium pressure is adjusted by changing the ratio of Sm to La and Ce to meet the charging and discharging dynamic performance of the electrode material; and zirconium (Zr) with an atomic ratio of 2-3% relative to the A side element is added to the A side element to improve the nucleation rate during solidification. The negative electrode material of the nickel-metal hydride battery obtained by using the hydrogen storage alloy thereof has a high overcharge resistance, a high rate discharge performance and a good cycle stability.