Ni-5％RExOy复合添加剂对Mg2Ni电化学储氢性能的影响

摘要

The Ni-5％ RExOy (CeO2,La2O3,Eu2O3) as composite additives,Mg2Ni-Ni-5 ％ RExOy composites were prepared by the ball milling method.The effects of different additives on the structure,morphology,electrochemistry and kinetic properties of Mg2 Ni alloy were studied systematically.The results show that composite additives can improve the proportion of amorphous and nanocrystalline structure of Mg2Ni alloy.The particle size is homogeneous but the agglomeration is observed in the sample with Ni-5％ CeO2 additives.The composites with additives show higher maximum discharge capacity and better cycle stabilities.All of these three kinds of composite additives can improve the kinetic properties of the composites effectively,including optimizing the charge-transfer ability,the reversibility of the electrochemical reaction on the alloy surface,and enhancing the diffusion coefficients of H atoms in the bulk of alloy.Among these three kinds of additives,Ni-5％CeO2 additive shows the best catalysis effect on promoting the kinetic properties of the composites.%以Ni-5％RExOy(CeO2,La2O3,Eu2O3)为复合添加剂,研究添加剂对球磨Mg2Ni合金的微观结构及电化学储氢性能的影响.结果表明:添加剂能够改变材料非晶与纳米晶结构的比例,复合材料的粒度分布均匀,但添加Ni-5％CeO2的样品存在少量团聚现象.含有添加剂的样品具有更高的最大放电容量及更好的循环稳定性;添加剂均可有效提高复合材料的充放氢动力学性能,改善材料表面电荷转移能力及电化学反应的可逆性,提高合金内部H原子的扩散速率.其中Ni-5％CeO2添加剂对提高复合材料动力学性能的催化效果最好.