Our innovation is an electrochemical method that employs lithium insertion battery type electrodes in a two-step selective process that applies an electrical current through a lithium selective electrode and a chloride selective electrode immersed in natural brine from salt flats:. Lithium chloride is then released by reversing the electrical polarity with the electrodes immersed in a recovery electrolyte. We have achieved the proof of concept, filed patents and at present we are developing the scale up electrochemical engineering for its industrial application. The electrochemical process has several advantages: short times (hours rather than months), low energy consumption using solar panels, high selectivity of lithium over sodium needed for battery grade lithium salts, and is environmentally friendly. A filter press type electrochemical reactor with a stack of alternating lithium manganese oxide cathodes reversible to lithium ions and polypyrrole anodes reversible to chloride ions, both supported on 3D carbon electrodes is being scaled up. Lithium-containing brine is flown perpendicular to the electrical current direction. Since the lithium ion capture is a spontaneous battery process generating energy, electricity from solar panels is converted into recovered lithium chloride in a second electrolysis step.
How it benefits society
This is a sustainable energy storage project from renewable energy sources (solar and wind) for remote electrification, environmentally friendly electric vehicles and widespread portable electronics. South America has 65% of the world lithium reserves and 80% of lithium containing brines at high altitude salt flats: Bolivia (Uyuni), Chile (Atacama) and Argentina (Puna). In south America 30 million people do not have access to electricity, i.e., a 7.5 GWh market for remote electrification based on renewable solar energy which will require batteries for off peak energy storage with a life time as long as the solar panels (15 years or more). Lithium ion batteries are well suited for this. The emergence of electric vehicles requires lithium, the lightest battery metal with high energy density, for replacing fossil fuels emitting CO, particulate matter and contributing to CO2 global warming. The present evaporation lithium extraction process from natural brines is very slow, losses millions of gallons of water per ton of lithium carbonate produced and releases sodium chloride and magnesium sulfate waste to the environment. Local communities, local governments and companies extracting lithium, manufacturing and using lithium batteries will benefit from our solution. Also local scientific and technology activities at the new lithium research center in Jujuy, Argentina will attract PhD students and young researchers worldwide.
What's unique about it
Solar energy is converted in extracted lithium chloride from brine to build lithium batteries and store intermittent renewable energy. The proposed solution is a clean, selective and environmentally friendly process that will employ solar energy to produce lithium salts from natural brine. Since lithium is extracted selectively with respect to sodium or magnesium in a two-step electrochemical process high quality battery grade lithium chloride is produced without altering the water balance of brine returned to the salt flat. The method does not release chemical waste to the environment. The energy consumption of our electrochemical method is low, some 0.7 kWh/Kg of lithium extracted which can be compared to 1 kWh per year to power a single iphone once a day. For a ton of lithium the energy needed, 700 kWh, can be compared to the charge required to power 10 laptops in a year (data from EPRI). The electricity needed for the novel extraction process comes from solar panels (at 2000$ per kW) and the capital cost per ton of lithium extracted is only 35 dollars in a 30 year long exploitation. Taking a cost of electricity of 10 cents of dollar per kWh, it will cost 70$ to produce a ton of lithium salt at a world market value of 12,000$ per ton. This novel solution, with patent applications does not alter the water balance or release waste to the environment, unlike the present evaporation soda-lime method and would enable establishing lithium mining service business.
Opportunity to scale
We have achieved the proof of concept of our solution to extract lithium from salt flats brine from electrochemical basic research to small scale reactor prototypes and have secured IP protection. The next challenge is to reach a self-contained mobile pilot plant with solar panel electricity supply, electrochemical reactors and pumping systems that can be taken to the high altitude salt flats for an industrial large scale demonstration. The challenge is to develop at large scale a completely new industrial process. For the scaling up we need to optimise mass transport of lithium and chloride ions, current distribution, electrical potential gradients and heat management. A major challenge to compete with the present industrial evaporation process to extract several thousand tons of lithium salts from natural brine is to carefully design reactors with large surface area 3 dimensional electrodes with optimum mass transport and using low cost materials. Since lithium is the lightest metal, a large electrical charge (27 Ampere.hour) is required every 7 grams, therefore very large electrodes surface area in multiple stack reactors is imperative. The battery type electrode material should also exhibit mechanical and chemical stability over many operation cycles in large scale operation. Therefore, funding is required for capital investment for equipment, supplies and engineering to reach an industrial pilot plant prototype in 1-2 years’ time.
INQUIMAE (CONICET) and University of Buenos Aires, School of Science, Prof. Dr. Ernesto Julio Calvo, Buenos Aires City and Jujuy Province (Argentina)
The Project team under direction of Prof. Ernesto J. Calvo at INQUIMAE and Buenos Aires University and the cooperation of Dr. Victoria Flexer at CIT-Jujuy and University of Jujuy has several research fellows, posdocts and PhD students funded by CONICET: MSc. Chemistry Florencia Marchini (Buenos Aires) studies the processes for lithium extraction and Chem. Eng. Valeria Romero (Jujuy) develops the engineering of electrochemical reactors for the extraction of lithium. The Institute of Chemical Physics for Materials, Environment and Energy (INQUIMAE) is jointly funded by the University of Buenos Aires (UBA) and the Argentine National Science and Technology Research Council (CONICET). Prof. Calvo is a specialist in electrochemistry with more than 160 publications (h = 35), holds a degree in Chemistry (UBA 1975) and a PhD in Chemistry (University of La Plata, Argentina 1979). After a postdoctoral fellowships at the Imperial College, UK (1979-1982) and a Senior Research Associate appointment at Case Western Reserve University Cleveland, US (1983-1984), he became Professor of Physical Chemistry at UBA and Senior Research Fellow of CONICET. At present he is Director of INQUIMAE and has been Vice-president of the International Society for Electrochemistry (2009-2011), Fellow of the RSC as well as Guggenheim Fellow 2000. In 2012 he started research in lithium electrochemistry. Dr. Victoria Flexer, after a PhD in chemistry (2007) at UBA, postdoctoral fellowships in France (2008-2010), Australia (2011-2012), and Belgium (2013-2016), has started as research leader in electrochemical research in a newly created Lithium Research Center in Jujuy, Argentina. The construction of Aa new building to host the Lithium Center is under way and expected to be completed by mid 2017. See http://www.inquimae.fcen.uba.ar/home.htm.