1984 was quite a year: it saw the birth of commercial giants Virgin Atlantic and Vodafone and Bob Geldof made us empty our wallets while Band Aid’s ‘Do they know it’s Christmas…?’ blasted out from car radios. But, most significantly in our line of work, chemical engineer Maria Skyllas-Kazacos conducted her first experiments on the Vanadium Redox Flow Battery (VRFB) at the University of New South Wales in Australia (UNSW).
Together in electric dreams
Back in the 1980s, the world was a very different place. In terms of energy and sustainability we were very much at the beginning of our green journey. Having recently contributed to a symposium marking the 40th anniversary of the invention of VRFB technology, I was reminded how far we have come – but crucially, what vanadium – and how we source it – means for our future.
Going with the flow
Put simply, a VRFB is an electrochemical energy storage system, consisting of two electrochemical half cells, separated by an ion exchange membrane. The batteries use vanadium ions as charge carriers, making the most of vanadium’s capacity to exist in four different oxidation states. Over the course of the past 40 years, from the first single 1kw battery built at UNSW, VRFBs have seen remarkable advancements in their technology and commercialisation, and multiple energy storage systems of different power levels have since been built worldwide.
From the Earth, with love
Identified as an element in its own right in 1831 after it was separated from a sample of cast iron by Swedish scientist Nils Gabriel Sefström, vanadium was named after the Nordic goddess of love, Vanadis. It is highly abundant and found in more than 60 minerals as well as phosphate rock, certain iron ores and some crude oils, with the largest established sources located in China, Russia, South Africa, Australia and Brazil.
As a material it is malleable, ductile and corrosion resistant – and used in a large majority of flow batteries – giving them a number of highly desirable properties, including:
Energy efficient – compared to alternative technologies, such as lithium-ion batteries, vanadium flow batteries (VRFB) offer a larger-scale, long-term energy storage option, much needed to enable green transition.
Long life span – more than 20,000 charge-discharge cycles over a lifetime of 15 to 20 years, with little or no risk of overcharging.
Safety – they are non-flammable and have a safe, aqueous electrolyte composed of vanadium-ions.
Eco friendly – mining vanadium is not as detrimental to the environment as other options, CO2 emissions are relatively low; vanadium electrolyte can be recycled.
Facing the future
The biggest challenge for safe and stable supply of vanadium is the fact that more than 80% of the global supply comes from Russia and China. In Europe, the situation is even more challenging – with no domestic extraction, Europe is fully dependent on imports, almost entirely from the two above countries. This is also why the EU has recognised vanadium as a Critical Raw Material (CRM), which are raw materials of high economic importance for the EU, yet with a high risk of supply disruption. Improvements are also required in the manufacture of VRFBs as many are still assembled by hand. Although reliable, there’s no doubt – as reiterated by my symposium colleague Dr. Thomas Lüth from CellCube – that automation would streamline production, boost efficiency and reduce costs.
Planning ahead However, there is some hope on the horizon. Through its 32 extraction licences for minerals in southwestern Norway, Norge Mineraler estimates that there are around 4.5 billion tonnes of resources of magmatic origin, which could, for decades to come, help secure a future supply of critical minerals and meet the requirements of society’s transition from fossil fuel to green energy. The company is making significant progress in its CRM exploration and aims to, among others, produce magnetite concentrate, a precursor to vanadium oxide, by 2029.
