TY - JOUR
T1 - Tailoring the equilibrium hydrogen pressure of TiFe via vanadium substitution
AU - Jung, Jee Yun
AU - Lee, Young Su
AU - Suh, Jin Yoo
AU - Huh, Joo Youl
AU - Cho, Young Whan
N1 - Funding Information:
This study was supported by the Korea Institute of Science and Technology (grant number 2E30201 ).
Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2021/2/15
Y1 - 2021/2/15
N2 - We present that the equilibrium hydrogen pressure of titanium iron (TiFe) alloy, a room-temperature hydrogen storage material, can be tailored via vanadium alloying. While many 3d transition metal alloying elements (e.g., Mn, Cr, Co, and Ni) typically replace the Fe sublattice in TiFe, vanadium can replace both the Ti and Fe sublattices. Density functional theory calculation predicts that the substitution of Ti with V yields a unique effect: the equilibrium pressures of TiFe/TiFeH (P1) and TiFeH/TiFeH2 (P2) are closer, resulting in a decreased P2/P1 ratio. Experimental pressure-composition isotherms confirm this theoretical prediction. The lower P2/P1 is beneficial because the two-step TiFe hydrogenation reactions can be contained within a narrow pressure range. In contrast, the substitution of V for Fe lowers both P1 and P2, but lowers P1 more, resulting in a higher P2/P1 ratio. The contrasting effects contingent on the substitution site is a crucial factor in alloy design. It highlights the significance of vanadium as a versatile alloying element that modifies the hydrogen storage property of TiFe.
AB - We present that the equilibrium hydrogen pressure of titanium iron (TiFe) alloy, a room-temperature hydrogen storage material, can be tailored via vanadium alloying. While many 3d transition metal alloying elements (e.g., Mn, Cr, Co, and Ni) typically replace the Fe sublattice in TiFe, vanadium can replace both the Ti and Fe sublattices. Density functional theory calculation predicts that the substitution of Ti with V yields a unique effect: the equilibrium pressures of TiFe/TiFeH (P1) and TiFeH/TiFeH2 (P2) are closer, resulting in a decreased P2/P1 ratio. Experimental pressure-composition isotherms confirm this theoretical prediction. The lower P2/P1 is beneficial because the two-step TiFe hydrogenation reactions can be contained within a narrow pressure range. In contrast, the substitution of V for Fe lowers both P1 and P2, but lowers P1 more, resulting in a higher P2/P1 ratio. The contrasting effects contingent on the substitution site is a crucial factor in alloy design. It highlights the significance of vanadium as a versatile alloying element that modifies the hydrogen storage property of TiFe.
KW - Computer simulations
KW - Hydrogen absorbing materials
KW - Metals and alloys
KW - Thermodynamic properties
UR - http://www.scopus.com/inward/record.url?scp=85091785446&partnerID=8YFLogxK
U2 - 10.1016/j.jallcom.2020.157263
DO - 10.1016/j.jallcom.2020.157263
M3 - Article
AN - SCOPUS:85091785446
SN - 0925-8388
VL - 854
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
M1 - 157263
ER -