Electrowinning of Lithium from Molten Salt Containing LiOH
O. Takeda a, M. Li a, M. Hoshi a and Y. Sato a
a Department of Metallurgy, Graduate School of Engineering, Tohoku University
6-6-02, Aramaki-Aza-Aoba, Aoba-ku, Sendai 980-8579, Japan
Abstract
Investigation on electrowinning of Li from molten salt containing LiOH was conducted in order to develop a system of storage and transportation for hydrogen by using LiH as a storage medium in this study. Electrolysis of LiOH in molten LiOH–42 mol% LiCl was tried, but Li metal was not obtained. A chemical potential diagram for Li-O-H was then constructed from thermochemical data for the analysis of side reactions, and a possibility of side reaction between Li metal and LiOH in the bath was revealed. Electrolysis of LiOH in molten LiCl–42 mol% KCl bath was tried by charging LiOH in an anode chamber shrouded……….
Introduction
Hydrogen is expected to contribute in energy saving by the improvement of energy efficiency with use of fuel cell and to contribute in reduction of environment burden matters such as CO2 and NOx. However, an effective supply system of hydrogen in a large scale has not yet been established at this stage. Based on the background, the authors have investigated the system for storage and transportation of hydrogen by using lithium hydride (LiH) as a storage medium…..
Experimental
Electrolysis of LiOH in LiOH-LiCl Bath
LiOH•H2O (>95%, Kanto Chemical Co. Inc.) was heated and held at 343 K in air for dehydration. Formation of LiOH was confirmed by using gravimetry and powder X-ray diffraction analysis (XRD). Anhydrous LiCl (>99%, Kanto Chemical Co. Inc.) was heated and held at 623 K under argon flow for 12 hours, and it was then fused under HCl gas flow in a quartz container….
Electrolytic Conditions The representative experimental apparatus is shown in Figure 3. Nickel rod (3 mm diameter) or tungsten wire (1 mm diameter) was used as a working electrode (cathode). Nickel rod (3 mm diameter) and graphite rod (6 mm) were used as a quasi-reference electrode and as a counter electrode (anode), respectively. LiCl–KCl prepared in advance was charged in a high purity alumina crucible. The tip of anode was shrouded with porous magnesia…..
Results and Discussion
Electrolysis of LiOH in LiOH-LiCl Bath
A redox wave corresponding to the deposition of lithium metal and an oxidation wave corresponding to the evolution of oxygen and water were observed in the cyclic voltammetry. Some redox waves unidentified were also observed. The peak of oxidation wave of lithium metal in a reverse scan was smaller than the peak of reduction wave for lithium deposition, which implied that lithium was consumed by a non-electrochemical cause….
Conclusions
Investigation on electrowinning of lithium from molten salt containing LiOH was conducted in order to develop a system of storage and transportation for hydrogen by using LiH as a storage medium in this study. Electrolysis of LiOH in molten LiOH–42 mol% LiCl was tried, but lithium metal…………..
Acknowledgement
References
1) I. Barin: Thermochemical Data of Pure Substances (1989, VCH Verlagsgesellschaft mbH, Weinheim, Germany).
2) G.J. Kipouros and D.R. Sadoway: JOM, 5 (May) (1998), 24-26.
3) T. Laude, T. Kobayashi and Y. Sato: International Journal of Hydrogen Energy, 35 (2010), 585-588.
4) M. Li, O. Takeda, M. Hoshi and Y. Sato: Abstracts of the 60th Annual Meeting of the International Society of Electrochemistry (2009).
5) A.W. McClaine, R.W. Breault, C. Larsen, R. Konduri, J. Rolfe, F. Becker and G. Miskolczy: Proceedings of the 2000 U.S. DOE Hydrogen Program Review, NREL/CP-570-28890 (2000).
6) O. Takeda, M. Li, M. Hoshi and Y. Sato: Abstracts of 41th Symposium Molten Salt Chemistry, Japan, 41 (2009), 41-42.
7) N.A. Reshetnikov, G.M. Unzhakov: Zhur. Neorg. Khim., 3 (1958), 1435.
8) T. Willace: Chemistry and Industry, 22 (1953), 876-.881.