Wang Yi, Wang Xin
Division of Chemical and Biomolecular Engineering, School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore.
Dalton Trans. 2008 Oct 28(40):5495-500. doi: 10.1039/b801213j. Epub 2008 May 7.
The Ce(5)Mg(41) hydrogen storage alloy was ball-milled with Ni powder, leading to the formation of a structure of inlaid metallic Ni nanocrystallites dispersed throughout a Ce-Mg amorphous alloy matrix. This structure was identified to have a positive effect on improving electrochemical hydrogen storage capacity. The ball-milled Ce(5)Mg(41) + 200 wt% Ni composite shows the highest initial discharge capacity (1046 mA h g(-1)) and high-rate dischargeability (HRD). Electrochemical impedance spectra, cyclic voltammograms and anodic polarization measurements show that the high discharge capacity and HRD was due to high hydrogen diffusivity and low reaction resistance. With a further increase in Ni content, the discharge capacity and HRD decreases, as a result of the excessively high reaction resistance due to the presence of an excessive oxide film of Ni(OH)(2). However, the cycling stability improves with the increase of Ni content in the nanocomposite.
将Ce(5)Mg(41)储氢合金与镍粉进行球磨，形成了镶嵌在Ce-Mg非晶合金基体中的金属镍纳米微晶结构。该结构被确定对提高电化学储氢容量有积极作用。球磨后的Ce(5)Mg(41)+200 wt% Ni复合材料表现出最高的初始放电容量(1046 mA h g(-1))和高倍率放电性能(HRD)。电化学阻抗谱、循环伏安图和阳极极化测量表明，高放电容量和HRD归因于高氢扩散率和低反应电阻。随着镍含量的进一步增加，放电容量和HRD降低，这是由于Ni(OH)(2)过量氧化膜的存在导致反应电阻过高。然而，纳米复合材料的循环稳定性随着镍含量的增加而提高。
