Authors: Yanghuan Zhang Zeming Yuan Hongwei Shang Yaqin Li Yan Qi Dongliang Zhao
Publish Date: 2017/03/10
Volume: 48, Issue: 5, Pages: 2472-2482
Abstract
In this paper the La08−x Ce02Y x MgNi35Co04Al01 x = 0 005 01 015 02 alloys were synthesized via smelting and melt spinning The effect of Y content on the structure and electrochemical hydrogen storage characteristics of the ascast and spun alloys was investigated The identifications of XRD and SEM demonstrate that the experimental alloys possess a major phase LaMgNi4 and a minor phase LaNi5 The variation of Y content results in an obvious transformation of the phase abundance rather than phase composition in the alloys namely LaMgNi4 phase increases while LaNi5 phase decreases with Y content growing Furthermore the replacement of Y for La causes the lattice constants and cell volume to clearly decrease and markedly refines the alloy grains The electrochemical tests reveal that these alloys can obtain the maximum values of discharge capacity at the first cycling without any activation needed With Y content growing the discharge capacity of the alloys obviously declines but its cycle stability remarkably improves Moreover the electrochemical dynamics of the alloys involving the highrate discharge ability hydrogen diffusion coefficient D limiting current density I L and charge transfer rate initially augment and then decrease with rising Y content
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