Abstract：La0.3Y0.7Ni3.25-xCoxMn0.15Al0.1（x=0~1.5）alloys of La-Y-Ni based A2B7-type were prepared by vacuum arc melting method and annealed at 1023k and 24h under the 0.2MPa high purity Ar atmosphere. The effect of Co element replacing Ni on the microstructure, phase structure and electrochemical properties of La-Y-Ni based A2B7-type alloys were systematically investigated via XRD, SEM, EDS and electrochemical test methods. The structure analysis showed that the alloy had a multiphase structure after annealing, including the following phases: Ce2Ni7-type, Gd2Co7-type, Ce5Co19-type, Pr5Co19-type and CeNi5-type, among which the Ce2Ni7-type andGd2Co7-type were the main phases. With the gradual increase of Co content, the abundance of Ce2Ni7-type main phase increased first and then decreased and the unit cell volume also gradually increased. With the increase of Co element, the charge-discharge cycle stability and discharge capacity of the alloy electrode increased first and then decreased. The maximum discharge capacity and the optimal cycle stability of the alloy electrode were 385.9mAh/g (x = 0.2) and 82.3% (x = 1.0) respectively.
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2021, Vol. 28 