表面纳米化处理对Nd-Mg-Ni系A2B7型合金大电流放电能力的影响

项目名称： 表面纳米化处理对Nd-Mg-Ni系A2B7型合金大电流放电能力的影响

项目编号： No.21303157

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 李媛

作者单位： 燕山大学

项目金额： 25万元

中文摘要： Nd-Mg-Ni系A2B7型合金有望成为高容量Ni/MH电池负极材料，然而其合金化元素选取受限，大电流放电能力改善程度受到影响。为了提高合金的大电流放电能力，本项目提出采用合金镀覆与高分子聚合物修饰的方法对合金进行表面纳米化处理。采用XRD、SEM、TEM、IR等方法研究处理条件对修饰层厚度、尺寸、形状、连续性等的影响。在不同处理时间下采样，分析合金表面修饰层的生长规律，为高效稳定修饰层的制备提供理论指导。测试未处理与经过表面纳米化处理的合金电极的电化学性能与电极过程动力学性能，总结修饰层对合金电极性能的影响规律。表征修饰层在合金充放电不同阶段与充放电循环中稳定性、连续性、微观结构与化学状态等的变化，从而揭示不同修饰层对合金大电流放电能力的影响机理，为选择高效稳定的修饰层、提高合金的大电流放电能力提供理论指导与基础数据。

中文关键词： A2B7型储氢合金；表面修饰；纳米化处理；电化学性能；大电流放电能力

英文摘要： Nd-Mg-Ni-based A2B7-type alloys are promising negative electrode materials for high capacity Ni/MH batteries. However, modification of their dischargeability at high current density has been limited owing to scale-limited alloying elements. In order to improve the dischargeability at high current density, in this project we intend to perform alloy coating and polymer modification, both with nano-scale on alloy surface. We study microstructure, thickness, size, shape and continuity of the modification layer by XRD, SEM, TEM and IR methods. We analyze specimens with different treating time to get forming mechanism of the modification layer, providing theoretical guidance for obtaining high catalytic activity and high stability modification layer. We test the electrochemical properties and electrochemical kinetics with and without nano-scaled modification layer, to investigate influence of modification layer. We characterize stability, continuity, microstructure and chemical state of modification layer to reveal influence and mechanism of modification layer on dischargeability at high current density of Nd-Mg-Ni-based A2B7-type alloys. The influence and mechanism will provide theoretical guidance and basic data for selecting high catalytic activity and high stability modification layer, and improve dischargeability

英文关键词： A2B7-type hydrogen storage alloys；surface modification；nano-scaled surface treatment；electrochemical properties；high rate dischargeability