How To Break Up With Your Toxic Acid
Recently, Oxford spinout FluoRok raised £7.7 million in an oversubscribed funding round that included investments from our friends at Volta. The investment will fund the expansion of their team and facilities that make LiPF6 without using HF.
Issy takes us through fluorine in batteries and the problem with HF featuring a special interview from Fluorok CEO and founder Dr Gabriele Pupo.
Fluorine is all around us. Its main natural reserve, fluorite (or fluorspar) critical mineral in the EU and US. Fluoride ions are put in water supplies for healthy teeth, fluorine is used to produce Teflon, aluminium, pharmaceuticals and agrochemicals, and it’s even a key part of uranium purification in power plants.
Fluorinating building blocks
Fluorine atoms are derived mostly from Fluorspar ore, around 55%-65% of which is produced in China. Industrially fluorinating something relies on the energy intensive treatment of fluorspar with sulfuric acid at high temperatures to generate hydrogen fluoride, which is stored as liquified gas. Hydrogen fluoride (HF) can be dissolved in water to form hydrofluoric acid. It is mostly used to make refrigerants, fluoropolymers and aluminium.
Hydrogen fluoride goes easily and quickly through the skin and into tissues in the body, and the F- ions can bind to intracellular calcium and magnesium, resulting in cell destruction and necrosis. Skin contact can cause severe burns that develop after several hours due to the H+ ions. Breathing it in case irritates the eyes, nose, and respiratory tract. LiPF6 forms HF in contact with water, such as in the air or on the skin, so electrolyte is particularly dangerous.
Any contact or breathing of HF is life-threatening at ppm levels of exposure, which is a completely different toxicity risk compared to other acids.
Fluorine in lithium-ion batteries
There are two key uses for fluorine in lithium-ion batteries: LiPF6 electrolyte salt and PVDF binder in the cathode.
Fluorine is also sometimes found elsewhere in a lithium ion battery, such as in a fluorinated additive to improve battery performance, or different emerging electrolyte salts such as LiFSI or TFSI.
PVDF is electrochemically stable, has good mechanical strength, and is used as a standard ‘glue’ for cathode materials. It requires NMP, a nasty solvent, to dissolve it which does make cathode slurries much more toxic than water based anode slurry.
LiPF6 is the dominant solute lithium salt in lithium ion batteries due to its low cost ($8/kg in our September battery component price report). The PF6- anion is very inert towards reducing agents, such as lithium metal, and also can passivate the aluminum current collector.
Interestingly, the price of LiPF6 has also dropped off a cliff in the last few years, more so than famously cheap LFP.
Making Electrolyte Salt
There are several different ways to produce LiPF6 at scale, and it’s almost entirely done in Asia Pacific using HF. Which exact route is used depends on the company, but the common ones via LiF and PF5, as shown below.
Fluorok: pairing fluorine without HF
Fluorok was spun out of the University of Oxford in 2022 by Professor Véronique Gouverneur and Dr Gabriele Pupo. Based at Arc Oxford, they are hoping to create a safer and more sustainable fluorination process to disrupt the entire industry. Their CEO, Dr Gabriele Pupo, answered our questions.
What’s your background and where did the idea for Fluorok come from?
I’m a chemist by training, I got my degree from the University of Torino, Italy back in 2012, then moved to Germany at the Max Planck Institut (Kohlenforschung) for my PhD where I had the pleasure of being trained in the field of catalysis in the group of Nobel laureate Benjamin List.
In 2017, I joined Veronique Gouverneur’s group at the University of Oxford; she leads one of the most respected groups in fluorination chemistry. Building on many years of research, in 2021 we discovered a solution to what has been a centuries-old academic and industrial problem, accessing fluorochemicals without relying on the intermediacy of hydrogen fluoride, one of the most toxic, hazardous, and difficult-to-handle chemicals.
From that first discovery, everything moved quickly, Veronique and I founded FluoRok in 2022, we spunout of the University of Oxford and secured a £3m ($3.9m) pre-seed round in 2022 led by Oxford Science Enterprises. Very recently we closed an oversubscribed £7.7m ($10m) seed round supported by an investor syndicate which included BGF, Green Generation Fund, battery and energy storage experts Volta Energy Technologies, and our current investors.
How is scaling up your process going and how will the investment round drive this forward?
We have a team of dedicated scientists and engineers who have transformed a gram-scale academic process into a kg+ industrial process. Progress has been fast thanks to our outstanding team with deep scientific, commercial, and industrial expertise and significant support from our investors and the UK government. This investment round will play a crucial role in further expanding the team, operations, and pilot facilities towards the first supply of our fluorinating reagents and LiPF6.
Your website talks about a paradigm shift for industrial processes around fluorination - do you have a vision for the bigger picture on how these industries need to change and evolve and what would you like to see?
At FluoRok, we believe 21st century (fluoro)chemical manufacturing should focus on five key pillars: sustainability, safety, supply localisation, cost-reduction, and circularity. Some of these aspects have been overlooked but growing geopolitical tensions and increased pressure on reducing our impact on the planet are changing this.
We aim to lead a shift in the sector through partnerships with major industrial players to develop solutions that are cost-effective but also safer and more sustainable. By building robust localised supply chains for key materials that we all depend on (such as LiPF6), we aim to reduce the reliance on foreign countries and showcase that innovation can unlock solutions that are both price-competitive and positive for the planet.
How do you see Fluorok’s future amid the increasing pressure and plans from the EU to ban PFAs - is sustainable fluorination the missing piece (particularly in batteries) or do you foresee fluorinated molecules eventually being replaced everywhere? What’s the solution here?
In general, there is a lot of confusion about fluorinated materials, polyfluorinated materials, and PFAS as the world has still not yet agreed on what PFAS are. We believe any incoming PFAS regulations should take a science-based approach and focus on subclasses of fluorinated materials that are known to pose a risk to humans or the environment.
In a broader context, fluorine occupies a very specific position in the periodic table (top-right), so most fluorine-containing chemicals have properties that make them irreplaceable except in very specific areas. Often these materials are high cost - due to the issues FluoRok’s technology addresses - so extensive efforts have already taken place to find replacements. The solution therefore comes from safe, efficient and sustainable production of fluorochemicals, and enhanced recycling of fluorinated materials (circular economy), all aspects that are central to FluoRok’s mission.
What’s your take on the price collapse of LiPF6: where do you see that going and how does that affect your business plans?
The EV market has indeed slowed down, but we also believe that electrification of the world is now well underway and will continue progressing. The LiPF6 price drop appears to be a consequence of temporary effects such as over-supply, and partially also due to the post-covid phase. In all scenarios, FluoRok will offer a highly competitive product with significant upsides such as supply localisation, increased sustainability and safer manufacturing.
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