Efficient,safe,and economical hydrogen storage technology is vital for hydrogen’s broad use as an energy carrier,with V-based BCC alloys standing out for their high theoretical storage capacity.However,the high cost ...Efficient,safe,and economical hydrogen storage technology is vital for hydrogen’s broad use as an energy carrier,with V-based BCC alloys standing out for their high theoretical storage capacity.However,the high cost of V has restricted their practical application.In this work,a cost-effective Ti–Cr–(Fe V80)alloy was successfully synthesized through a pre-refinement process involving the addition of Y/Zr to the Fe V80 alloy.The resulting Ti_(27)Cr_(27)(Fe V80+Y)_(46)alloy exhibited an effective dehydriding capacity of 2.3 wt%,with a capacity retention rate of 97.2%after 200 cycles.Through the analysis of HSC Chemistry 6.0 software and backscattered electron(BSE),it has been discovered that the prerefinement process significantly reduces the presence of Al,Si,and O impurities,leading to improved compositional uniformity.After the re-refinement,the formation of the Ti–rich phases had been notably curbed.This,along with a marked decrease in the pressure–composition–temperature(PCT)curve’s slope factor from 1.58 to 0.36,results in enhanced hydriding capacity(from 3.2 wt%to 3.7 wt%),reversible dehydriding capacity(from 2.0 wt%to 2.3 wt%),and a remarkable increase in the capacity retention rate(from 75.8%to 97.2%).The kinetics and thermodynamic properties of the alloys were calculated using the Arrhenius and Van’t Hoff equations,providing insights into their performance characteristics.The mechanism behind the alloy’s improved cyclic stability has been elucidated through an analysis of lattice distortion and X-ray photoelectron spectroscopy(XPS).These findings open new routes for the development of cost-effective Fe V80-based hydrogen storage materials.展开更多
基金financially supported by the National Key R&D Program of China(No.2022YFB3504700)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA0400304)the Research Fund of Key Laboratory of Rare Earth,Chinese Academy of Sciences(No.E32PF00116)。
文摘Efficient,safe,and economical hydrogen storage technology is vital for hydrogen’s broad use as an energy carrier,with V-based BCC alloys standing out for their high theoretical storage capacity.However,the high cost of V has restricted their practical application.In this work,a cost-effective Ti–Cr–(Fe V80)alloy was successfully synthesized through a pre-refinement process involving the addition of Y/Zr to the Fe V80 alloy.The resulting Ti_(27)Cr_(27)(Fe V80+Y)_(46)alloy exhibited an effective dehydriding capacity of 2.3 wt%,with a capacity retention rate of 97.2%after 200 cycles.Through the analysis of HSC Chemistry 6.0 software and backscattered electron(BSE),it has been discovered that the prerefinement process significantly reduces the presence of Al,Si,and O impurities,leading to improved compositional uniformity.After the re-refinement,the formation of the Ti–rich phases had been notably curbed.This,along with a marked decrease in the pressure–composition–temperature(PCT)curve’s slope factor from 1.58 to 0.36,results in enhanced hydriding capacity(from 3.2 wt%to 3.7 wt%),reversible dehydriding capacity(from 2.0 wt%to 2.3 wt%),and a remarkable increase in the capacity retention rate(from 75.8%to 97.2%).The kinetics and thermodynamic properties of the alloys were calculated using the Arrhenius and Van’t Hoff equations,providing insights into their performance characteristics.The mechanism behind the alloy’s improved cyclic stability has been elucidated through an analysis of lattice distortion and X-ray photoelectron spectroscopy(XPS).These findings open new routes for the development of cost-effective Fe V80-based hydrogen storage materials.
文摘分析了Al,Si,C热还原制备FeV50合金的热力学可行性及铝热还原过程渣金钒铝平衡,采用分期梯度配铝的方式,考察了原料配比、反应温度、加料制度和多期配铝系数对渣中TV含量及合金成分的影响。通过不同还原剂热还原的热力学分析表明:1500 K时,常压条件下碳热还原过程优先生成VC,只有当体系真空度高于76.8 Pa才能得到稳定钒基合金产品;硅热反应仅适用于高价钒氧化物的还原,配加CaO有利于反应的进行以及钒氧化物的还原效率;铝热还原V_2O_5和V_2O_3的单位反应热分别为368.4和221.0 k J·mol^(-1),基本能够满足密闭系统维持自发反应的热量需求。铝热还原渣金热力学平衡分析结果表明FeV50渣中TV含量随合金Al含量的升高而降低,当合金Al含量为2.0%时,渣中理论TV含量为0.27%;若要使渣中理论TV含量降低到0.15%,合金Al含量需达18.8%以上。基于此,采用"梯度配铝"工艺试验,在三期加料制度4-3-1,配铝系数1.30-1.00-0.30,原料配比3∶1,体系温度1850℃的条件下,渣中平均TV含量由均匀配铝的1.85%降低到0.69%,合金Al含量从1.6%降低到0.4%。
