【作者】 杭州明；

【导师】 赵敏寿；

【作者基本信息】 燕山大学 ， 材料学， 2006， 硕士

【摘要】 本文以改善V基固溶体合金的电化学性能为目的,在对贮氢合金研究现状进行了深入分析的基础上,从Ti-Zr-V-Mn合金入手,进行了一系列组分优化的研究工作。 利用XRD、SEM-EDS分析手段,研究了合金Ti_0.4Zr_0.1V_1.1Mn_0.5Cr_0.1Ni_x、Ti_0.4Zr_0.1V_1.1Mn_0.5Ni_0.4Cr_x、Ti_0.4Zr_0.1V_xMn_0.5Ni_0.3Cr_0.1和Ti_0.4Zr_0.1V_1.1Mn_xNi_0.4-Cr_0.2的结构、表面形貌及组成,研究结果表明这些合金均由BCC主相和C14 Laves第二相组成,且第二相沿着主相晶界析出,形成网状结构,起到了电催化相和微集流体的作用。 通过测定放电容量、荷电保持率、高倍率放电、容量保持率,研究了不同元素含量对合金电化学性能的影响。结果表明,Ni的添加促进了第二相的生成,改善了合金电极的电催化活性,20℃下,随Ni含量的增加,合金电极的各项电化学性能均得到改善,x=0.4时,最高放电容量为398.2mAh/g,x=0.8时,容量保持率S₉₀高达84.3%;Cr的添加虽延长了合金的循环寿命,但却使合金的放电电压曲线由两个平台减为一个平台,降低了最大放电容量;Mn含量的增加,改善了合会的高倍率放电性能;V含量的增加,提高了合金的荷电保持率。更多还原

【Abstract】 The purpose of this work is to improve electrochemical performance of V-based solid solution alloy. In this paper, compositon optimizing on Ti-Zr-V-Mn alloy has been done, based on deeply analysis on current situation of research on hydrogen storage alloy.The structure, surface morphology and composition of the Ti_0.4Zr_0.1V_1.1Mn_0.5Cr_0.1Ni_x, Ti_0.4Zr_0.1V_1.1Mn_0.5Ni_0.4Cr_x , Ti_0.4Zr_0.1V_xMn_0.5Ni_0.3-Cr_0.1 and Ti_0.4Zr_0.1V_1.1Mn_xNi_0.4Cr_0.2 alloys were investigated by means of XRD and SEM-EDS analyses. It is shown that these alloys all consist of BCC main phase and C14 Laves secondary phase. And the secondary phase precipitates along the grain boundary in the form of a network, which serves as a electrocatalyst and micro-current collector.The Influence of different element content on electrochemical performance of the alloy is also investigated by measuring discharge capacity, charge retention, high-rate dischargeability and capacity retention. Addition of Ni improves electrocatalytical activity of the alloy. At 20°C, the electrochemical performance of the alloy is improved when the Ni content is increased. And the maxium discharge capacity is 398.2mAh/g at x=0.4, the capacity retention S₉₀ is up to 84.3% at x=0.8. Addition of Cr raises cycle life with decreasing maximum discharge capacity owing to the decrease of two voltage plateaus to one voltage plateau on the discharge voltage curve, and the increase in Mn and V leads to the improvements of high-rate dischargeability and charge retention respectively.更多还原