bi-ION – Energy of the Future

The nanoFlowcell® works according to the principle of a redox flow battery (RFB) or flow cell and is often also referred to as a liquid battery. This definition points to an important characteristic of the nanoFlowcell® - it produces electricity from liquids. When paired with flow cells, these liquids are known as electrolyte solutions.

In the case of bi-ION, this electrolyte solution consists of a conductive liquid - organic and inorganic salts dissolved in water - and the electrolytes themselves, a molecule developed in the Digilab run by nanoFlowcell Holdings Ltd, modified on a nano-technical level. Or, to put it another way - nano-particles.

Dissolved redox salts are responsible for the energy transfer in conventional redox flow batteries. In bi-ION, the energy storage medium is suspended nano-particles that permit a considerably higher energy density than regular redox electrolyte liquids.

The composition of this molecule (electrolyte) and its concentration within the solution permits an energy density that is exceptionally high for electrolyte solutions (> 600 Wh/l). The electrolyte stores electrical energy in chemical bonds. It contains the ions that are crucial for the reaction process and is the chemical compound in bi-ION that dissociates ions. The precise molecular structure is a proprietary secret belonging to nanoFlowcell Holdings and the subject of ongoing flow cell research being carried out by the company.

In contrast to other research institutes, the work done by nanoFlowcell Holdings is entirely privately financed. For this reason, the company also does not wish to apply for patent protection for the chemical composition of the bi-ION electrolytes and the membrane structure of nanoFlowcell® prior to the start of commercialisation, nor reveal details of its production process. Other research institutes are working feverishly on mobile flow batteries, but the company estimates that it still maintains a comfortable technological lead over competing redox flow cell systems.

bi-ION^® electrolyte solutions. Coloured here to differentiate between positively and negatively charged solutions

The special electrolyte solution used in the nanoFlowcell® is not called bi-ION for nothing. The word bi-ION stands for "bi", as in two, and "ION", as in ions. Although we consistently speak of the bi-ION electrolyte liquid (singular), it is in fact two electrolyte liquids - one positively charged electrolyte and one negatively charged electrolyte. Despite this charge, the conductive liquid itself is electrically neutral.

The two energy-storing electrolytes circulate in two separate circuits, between which an exchange of positive and negative ions occurs across a special membrane in the nanoFlowcell's® voltaic cell. Inside the cell, the chemical reaction itself takes place in the form of reduction or oxidation, releasing electrical energy. In short, chemical energy is converted into electrical energy.

This process neutralises the electrolytes. In contrast to conventional redox flow cells, in which the discharging process is reversible, i.e. the electrolytes can be "recharged", the process in the nanoFlowcell® is irreversible. Following discharge, bi-ION cannot be recharged.

The nanoFlowcell® system is flexible in its design and can be adapted to the requirements of different applications. In the case of mobile applications, an open system was chosen. The energy-storing electrolytes are kept outside the cell in separate tanks. To avoid having to carry spent electrolyte around unnecessarily and thus empty the tanks, the spent electrolyte solution in an electric car powered by a nanoFlowcell® is released while driving. This means the used electrolyte solutions are filtered, the small quantities of solids stored in the filter and the remaining liquid released into the atmosphere as pure water. The filter has to be renewed after a distance of around 10,000 kilometres or a volumetric throughput of around 1,500 to 2,000 litres of bi-ION. Depending on the application requirements, the filter can be designed to be 100 percent recyclable.

The tanks can be refilled at fuel stations and the accumulator thus "recharged" with fresh bi-ION. There is no onerous changeover procedure for the electrolyte liquids, let alone a requirement to swap the entire accumulator with its transformer technology and casing.

One special feature of the nanoFlowcell® (also known as tertiary cells) compared with primary cells (batteries) and secondary cells (accumulators) is not only that the chemical energy carrier is stored outside the cell, but also that an external supply of it can be continuously maintained. The free and independently adjustable scalability of energy volume and power output makes it possible to deliver a constant supply of electrolyte solution, which permits continual operation of the nanoFlowcell® with no theoretical time limit, and likewise, a flow of energy with no theoretical time limit - a characteristic that makes the nanoFlowcell® increasingly interesting for terrestrial applications (keyword: small grid).

And on top of that, the nanoFlowcell® system has extremely low self-discharge and a high shelf life. The latter is based on the fact that the membrane itself is not subject to any chemical reaction during the electrolyte reaction and therefore does not degenerate. The company provides a hardware guarantee for the nanoFlowcell® of 50,000 operating hours. In an electric vehicle at an average speed of 45 km/h, this equates to a distance of 2.25 million kilometres.

The production of bi-ION involves a highly complex procedure with several production stages. Although currently made in laboratory quantities, there are no limits to manufacturing bi-ION on an industrial scale. An initial prototype facility has a production capacity capable of filling more than 40 tankers with bi-ION - every day. All chemical substances are neutralised in terms of their health and environmental impact in the course of the production process. There are no toxic or hazardous by-products or waste materials in this process. Instead, production residuals are recycled back into the production cycle.

The production of bi-ION requires energy. The precise energy values are dependent on the design of the production facilities. In an ideally configured production process, considerably less than one kWh of electricity is needed to produce an amount of bi-ION with the energy equivalent of one kWh (Ed: as with other energy carriers, too, this does not include the extraction of the raw materials). In large-scale production, the purely production costs (including the raw material used) are less than 0.10 euros per litre of bi-ION electrolyte solution. An illustrative bi-ION production facility would have a production volume of around two million litres per day (approx. 1.2 MW). This kind of production volume is sufficient to continuously supply around 300,000 nanoFlowcell-driven electric vehicles with bi-ION.

The raw materials necessary for the production of bi-ION are readily available almost anywhere in the world, are not subject to any restrictions and are economical to extract. This means that bi-ION - in contrast to crude oil, coal or lithium-ion batteries - is a non-political energy carrier. If it were up to nanoFlowcell Holdings, every country would be able to produce its own bi-ION locally, and thus independently cover its local energy needs in mobile and terrestrial applications. The distribution and sales infrastructure could be the same as that for petrol and diesel fuels. In future, car drivers would be able to fill up their nanoFlowcell-powered vehicles conveniently as usual at fuel stations in the space of just a few minutes - just with clean bi-ION instead of fossil fuels.

Charging lithium-ion batteries generates charging losses that can be as high as 20 percent. Consequently, charging a 50 kWh li-ion battery takes around 60 kWh of electricity. Many factors determine the efficiency of the charging process, with rapid charging producing greater deficits than regular charging carried out over several hours. For a range of 100 kilometres, a conventional electric car needs around 16 kWh.

By way of comparison, a fuel cell vehicle requires around one kilogram of hydrogen for the same range of 100 kilometres. However, producing one kilogram of hydrogen using electrolysis takes 100 kWh of energy. In the case of hydrogen, at least 50 percent of the energy is lost between electrolysis and the hydrogen fuel station - on compression, liquification, transport, filling etc. Without the downstream inefficiencies, simply manufacturing one kilogram of hydrogen takes around 55 kWh of electricity.

By way of comparison, a fuel cell vehicle requires around one kilogram of hydrogen for the same range of 100 kilometres. However, producing one kilogram of hydrogen using electrolysis takes 100 kWh of energy. In the case of hydrogen, at least 50 percent of the energy is lost between electrolysis and the hydrogen fuel station - on compression, liquification, transport, filling etc. Without the downstream inefficiencies, simply manufacturing one kilogram of hydrogen takes around 55 kWh of electricity.

In comparison to the apparently superior solution with lithium-ion batteries as the source of drive energy in electric vehicles, nanoFlowcell® makes a compelling case as the more efficient, practicable and environmentally compatible system. Because the production of bi-ION is not bound by any spatial or geographical restrictions, production locations with renewable energy sources (sun, wind, tides etc.) are ideally suited for the environmentally friendly and sustainably structured production of bi-ION. In contrast to regular e-vehicles, which draw their electricity "from the socket" - electricity that is currently almost exclusively generated from coal or nuclear power stations - no fossil energy carriers are burnt in the production of bi-ION. nanoFlowcell Holdings supports renewable energies for the generation of the electricity needed to produce bi-ION.

bi-ION thus has the potential to become the major energy carrier of the future. Its energy density is compelling. As things stand, hydrogen and lithium-ion batteries simply transfer the CO₂ emissions problem elsewhere, while bi-ION doesn't generate them in the first place. The production and use of bi-ION in nanoFlowcell does not generate excessive or harmful greenhouse gases. Quite the opposite, in fact. When renewably generated, bi-ION energy makes an important contribution to environmental protection.