EFFECT OF Ni/La RATIO ON PHASE STRUCTURE AND ELECTROCHEMICAL PROPERTIES OF A ₅ B ₁₉ -TYPE La ₄ MgNi ₁₉ HYDROGEN STORAGE ALLOY

A vacuum sintering method in a silica tube furnace was used to prepare La 4 MgNi[Formula: see text] alloys with LaNi[Formula: see text] and Mg 2 Ni in different nickel (Ni)/Lanthanum (La) ratios (Ni/La[Formula: see text] [Formula: see text] [Formula: see text]3.6–4.4), and the phase structure and electrochemical properties of the alloys were studied. XRD analysis shows that the increase of Ni/La ratio in this range promotes the formation of La 4 MgNi[Formula: see text] (Pr 5 Co[Formula: see text] type) phase from 3.79% (Ni/La[Formula: see text] [Formula: see text] [Formula: see text]3.6) to 47.98% (Ni/La[Formula: see text] [Formula: see text] [Formula: see text]4.4). The electrochemical testing results show that with the increase of Ni/La ratio, the maximum discharge capacity increases from 140.32[Formula: see text]mAh/g (Ni/La[Formula: see text] [Formula: see text] [Formula: see text]3.6) to 195.75[Formula: see text]mAh/g (Ni/La[Formula: see text] [Formula: see text] [Formula: see text]4.4). Each alloy shows good cycling stability, and their cycling capacity retention (S[Formula: see text]) is higher than 82%. It is found that the HRD[Formula: see text] of alloys with a higher Ni/La ratio exhibits better high-rate discharge ability due to the increasing amount of La 4 MgNi[Formula: see text] phase (Pr 5 Co[Formula: see text] type), which has excellent high-rate discharge ability.