镁在Zr-Ti-Mg-Ni-Mn-V-Fe高熵合金中的原子占位及对储氢性能的影响  

Atomic Occupation of Mg in Zr-Ti-Mg-Ni-Mn-V-Fe High-entropy Alloy and Its Effect on Hydrogen Storage Property

作　　者：陈治中 尹福虎 胡泊涛 斯庭智[1] CHEN Zhizhong;YIN Fuhu;HU Botao;SI Tingzhi*(School of Materials Science and Engineering,Anhui University of Technology,Maanshan 243002,China)

机构地区：[1]安徽工业大学材料科学与工程学院,马鞍山243002

出　　处：《高等学校化学学报》2025年第3期144-151,共8页Chemical Journal of Chinese Universities

基　　金：安徽省高校自然科学研究重大项目(批准号:KJ2020ZD26)资助。

摘　　要：通过Mg的添加,设计制备了3种A原子过计量的AB_(2)型Zr_(0.85)Ti_(0.15)Mg_(x)Ni_(1.20)Mn_(0.56)V_(0.12)Fe_(0.12)(x=0.20,0.25,0.30)高熵合金,探究了Mg添加量及其原子占位对储氢性能的影响.结果表明,所有合金均为C15 Laves单相结构,当x从0.20增至0.30时,合金的储氢量由0.35%(质量分数)显著提升至1.03%;合金具有优良的热力学性能,其中,Mg_(0.30)合金的放氢焓变(ΔH_(d))仅为28.93 kJ/mol;Mg_(0.30)合金的放电容量为167.0 mA·h/g,30次充放电循环后容量保持率为80.9%,展现了较好的电化学储氢性能.Rietveld全谱拟合结果揭示,Mg原子既占据Laves相A原子的8a位置,又占据B原子的16d位置;随着x的增加,8a位置的占位因子(g)保持恒定,而16d位置的g增加.这一结果不仅导致合金四面体间隙的增大,还促进了对氢强亲和力的四面体间隙的形成,从而显著提高了合金的储氢能力.In this study,A atom overstoichiometric AB_(2)-type high-entropy alloys of the composition Zr_(0.85)Ti_(0.15)Mg_(x)Ni_(1.20)Mn_(0.56)V_(0.120)Fe_(0.12)(x=0.20,0.25,0.30)were designed and synthesized by adding magnesium(Mg).The impact of Mg atomic occupation on the hydrogen storage properties was investigated.The results showed that all the alloys formed a single C15 Laves phase.Notably,the hydrogen storage capacity increased significantly,from0.35%(mass fraction)for the alloy with x=0.20 to 1.03%for the alloy with x=0.30.The alloys also exhibited excellent thermodynamic properties,with the Mg_(0.30)alloy achieving a low hydrogen desorption enthalpy(ΔH_(d)=28.93 kJ/mol).Furthermore,the Mg_(0.30)alloy demonstrated good electrochemical performance,with a discharge capacity of167.0 mA·h/g and a capacity retention of 80.9%after 30 charge-discharge cycles.X-ray diffraction(XRD)Rietveld refinement revealed that Mg atoms occupy the 8a and 16d sites in the Laves phase.As x increased,the occupation factor(g)at the 8a site remained constant,while g at the 16d site increased,leading to an expansion of the tetrahedral volume in the alloys.This structural change promoted the formation of tetrahedral interstitials with a strong affinity for hydrogen,which significantly enhanced the hydrogen storage capacity.

关 键 词：高熵合金 LAVES相 原子占位 储氢性能 四面体间隙 

分 类 号：O646[理学—物理化学] TG139.7[理学—化学]