Microstructure and electrochemical properties of La1 − xCaxNi3.2Co0.3Al0.3 hydrogen storage electrode alloys

A new low cobalt hydrogen storage electrode alloys La1 − xCaxNi3.2Co0.3Al0.3 (0 ≤ x ≤ 0.4) was developed. The microstructure and electrochemical properties were investigated and the results showed that the prepared alloys were basically composed of LaNi5 as matrix phase and LaNi3 as second phase (x ≤ 0.1). The second phase LaNi3 is substituted by a new phase Al(NiCo)3 gradually with increasing Ca content, and cycle stability is improved correspondingly. The highest discharge capacity can reach to 295 mAh g−1 (x = 0.2) and it can remain 82.5% (x = 0.2) after 300 charge/discharge cycles.