A first experimental and theoretical modelling of thermodynamic properties of pseudo-ternary LiBH4-NaBH4-KBH4 system Erika M. Dematteis,a)b) Eugenio R. Pinatel,b) Marta Corno,b) Torben R. Jensena) and Marcello Bariccob) DEPARTMENT OF CHEMISTRY a) AARHUS UNIVERSITY
Data: Experimental Ab initio literature
DEPARTMENT OF CHEMISTRY
Motivation
b) UNIVERSITY OF TURIN
Borohydrides for solid-state H2 storage
1.
Infiltration of eutectic mixtures to improve release and uptake of H2 Full evaluation of thermodynamic properties fundamental for tailoring
Investigation of pure compounds 2.
Investigation of binary systems and their interaction parameters
3. Extrapolation of ternary system 4.
Thermodynamic database with assessed functions
SR-PXD data (λ=0.8259, heating and cooling ΔT/Δt=5°C/min) of extrapolated ternary eutectic (LIQΩTER=0 kJ/mol)
DSC data (cooling ramp ΔT/Δt=2°C/min) of extrapolated ternary eutectic (LIQΩTER=0 kJ/mol and LIQΩTER= -14 kJ/mol)
LiBH4-NaBH4-KBH4 LiBH4-NaBH4
Calphad approach to assess phase diagrams: 𝑒𝑥𝑐 𝐺𝑚 = 𝑥1 𝑥2 0 𝐿12 + 1 𝐿12 (𝑥1 − 𝑥2 ) if k=0 : Regular solution if k≥1 : Redlich-kister Ternary : Muggianu’s rule
Experimental : Calculated : ΔHmelt = 6990 J/mol ΔHmelt = 7070 J/mol 70.0 mol% LiBH4 71.0 mol% LiBH4 T = 489 K T = 492 K
Ternary : Literature : T = 369 K 69 mol% LiBH4 - 7 mol% NaBH4 - 24 mol% KBH4
Calculated LIQΩTER=0 kJ/mol : 65 mol% LiBH4 - 8 mol% NaBH4 - 27 mol% KBH4 T = 384 K Calculated LIQΩTER=-14 kJ/mol : 66 mol% LiBH4 - 11 mol% NaBH4 - 23 mol% KBH4 T = 375 K
NaBH4-KBH4 LiBH4-KBH4
Conclusions Assessment of binary systems and good agreement with experimental data
Experimental : ΔHmelt = 12645 J/mol 68.2 mol% NaBH4 T = 741 K
Calculated : ΔHmelt = 15331 J/mol 68.2 mol% NaBH4 T = 741 K
assessment of ternary system based on new experiments Experimental : ΔHmelt = 11025 J/mol 72.5 mol% LiBH4 T = 377 K
Calculated : ΔHmelt = 9828 J/mol 72.3 mol% LiBH4 T = 382 K
References Y.M. Muggianu, M. Gambino, J.P. Bros, J. de Chimie Physique, 1975, 72, 83-88. E.M. Dematteis, E. Roedern, E.R. Pinatel, M. Corno, T.R. Jensen, M. Baricco, RSC Adv., 2016, 6, 60101–60108. R.M. Adams, Borax to boranes, Advances in Chemistry, 1961, 32. K.N. Semenenko, A.P. Chavgun, V.N. Surov, Russ. Jour. of Inorg. Chem., 1971, 16, 271–273. M.B. Ley, E. Roedern, T.R. Jensen, Phys. Chem. Chem. Phys., 2014, 16, 24194–24199. S.R.H. Jensen, L.H. Jepsen, J. Skibsted, T.R. Jensen, J. Phys. Chem. C, 2015, 119, 27919–27929. Huff, G. F. US 2,935,428, 1960.
Negative enthalpies of mixing suggest attractive interaction in the liquid state
Contact Erika Michela Dematteis
[email protected]
Acknowledgements
