Can Flow Batteries Finally Beat Lithium?

Published 27 December 2023 by

Martin Hamilton

Electric vehicles have been gaining popularity in recent years as a more environmentally friendly mode of transportation. However, one of the main concerns with EVs is their limited range and the time it takes to recharge their batteries. This is where flow batteries come in – a design in which spent electrolyte is replaced rather than recharged. Flow batteries are safe, stable, long-lasting, and easily refilled, making them ideal for balancing the grid, providing uninterrupted power, and backing up sources of electricity.

Flow Batteries: The Future of Energy Storage

A new kind of fluid called a nanoelectrofuel has been developed for flow batteries, which can store 15 to 25 times more energy than a traditional flow battery of comparable size. This breakthrough could make it possible to create a battery system small enough for use in an electric vehicle and energy-dense enough to provide the range and speedy refill of a gasoline-powered vehicle. The Strategic Technology Office of the U.S. Defense Advanced Research Projects Agency (DARPA) is currently pursuing this project as part of a drive to ease the military’s deployment of all-electric supply vehicles by 2030 and of EV tactical vehicles by 2050. If successful, this new flow battery could revolutionize the electrification of transportation and provide a solution to the current limitations of EVs.

Flow batteries are safe and long-lived

Flow batteries have a number of advantages over traditional lithium-ion batteries. One of the most significant is their safety. Lithium-ion batteries can be prone to overheating and even catching fire, but flow batteries are much less likely to experience these issues. This is because the chemical solutions used in flow batteries are non-flammable and non-toxic.

Another advantage of flow batteries is their long lifespan. While lithium-ion batteries typically last between 5 and 15 years, flow batteries can last up to 25 years or more with proper maintenance. This is because the chemical solutions used in flow batteries do not degrade over time in the same way that the electrodes in lithium-ion batteries do.

In addition to their safety and longevity, flow batteries are also highly scalable. This means that they can be used for a wide range of applications, from small-scale residential energy storage to large-scale grid storage. Flow batteries can also be easily expanded or downsized depending on the needs of the user.

One of the main drawbacks of flow batteries, however, is their relatively low energy density. This means that they are not as energy-dense as lithium-ion batteries, which can make them unsuitable for certain applications. However, researchers are working to improve the energy density of flow batteries by developing new materials and designs.

Overall, flow batteries are a promising technology that offer a number of advantages over traditional lithium-ion batteries. While they may not be suitable for every application, they are well-suited for many applications that require high levels of safety, reliability, and scalability. As research continues, it is likely that flow batteries will become an increasingly important part of the energy storage landscape.

Nanoparticles Boost Flow Battery’s Energy Density

Nanofluids, which are suspensions of nanoparticles, have been found to be an effective way to increase the capacity of flow batteries. These particles undergo redox reactions at the electrode surface, similar to the way dissolved ions react in conventional flow batteries. However, nanofluids are more energy-dense and can make up to 80% of the liquid’s weight while leaving it no more viscous than motor oil.

In 2009, researchers at Argonne National Laboratory and the Illinois Institute of Technology investigated the use of nanofluids suspended in water-based electrolytes for flow batteries. They found that the nanofluids could be used in a system with an energy-storing potential approaching that of a lithium-ion battery, with the pumpable recharging of a flow battery. Moreover, the nanoscale particles could be made from readily available, inexpensive minerals, such as ferric oxide and gamma manganese dioxide for the anode and cathode materials, respectively.

Influit Energy, a company founded by several of the principal investigators, is now commercializing the technology. With the basic science problem resolved, the company is developing a battery with an energy density rated at 550 to 850 watt-hours per kilogram or higher, as compared to 200 to 350 Wh/kg for a standard EV lithium-ion battery. The nanoelectrofuel can be reused at least as many times as a flow battery, and it will probably be cheaper.

The nanofluids are engineered to remain suspended indefinitely, unlike other suspensions, such as sand in water. The indefinite suspension helps the particles move through the system and make contact with the electrodes. Additionally, because the nanoelectrofuel is an aqueous suspension, it did not catch fire or explode, nor would the material be hazardous if the battery were to leak. The battery possessed a wide operational range of between -40 °C and 80 °C.

Influit’s design is unique in that it uses nanofluids instead of conventional flow batteries. The company expects larger versions would also beat old-style flow batteries at backing up the grid because the nanoelectrofuel can be reused at least as many times as a flow battery—10,000 or more cycles—and it will probably be cheaper.

The nanoelectrofuel can be produced as needed and could eventually replace fossil fuels. The fuel can be transported to depots much as gasoline is today, either by tanker trucks or via existing upgraded pipelines. At the depot, the spent fuel can be recharged with electricity from any source—solar, wind, hydroelectric, nuclear, or fossil fuels. The recharging can also be done at a service station or in the EV itself. In the latter case, the recharging would work just as it does for today’s battery electric vehicles.

In the event of a tanker crash or a pipeline rupture, the NEF turns into a pastelike substance that can be easily cleaned up. The collected material is the most valuable part of the battery, and there are processes to easily reconstitute the active material into a new nanofluid that can be reused.

Designing a Flow Battery for Electric Vehicles

In the race to find the ideal battery for electric vehicles, nanoelectrofuel flow batteries have emerged as a promising alternative to lithium-ion batteries. The current generation of nanoelectrofuel developed by Influit, along with the entire ecosystem needed to produce, distribute, and recycle the fuel, is expected to cost $130/kWh when used in an EV. In comparison, lithium-ion batteries cost around $138/kWh.

While lithium-ion batteries are expected to drop below $100/kWh in a few years, Influit’s next-generation nanoelectrofuel is projected to cost even less, around $50 to $80/kWh. This next-gen system is expected to have five times the energy density of present Li-ion systems.

The energy density of a flow battery is directly proportional to the range of an EV. A typical EV battery today occupies about the same volume as a flow battery with 400 liters of nanoelectrofuel. If nanoparticles make up 30 percent of the weight of that fuel, the EV would have a range of only 105 km. However, if the nanoparticle content is raised to 40 percent, the range would climb to 274 km. At 50 percent, it hits 362 km, and at 80 percent, it can go as far as 724 km (450 miles), assuming the flow battery’s tank remains the same size.

Influit has already achieved the 50 percent nanoparticle content mark and has demonstrated an 80 percent nanoelectrofuel, according to Aaron Kofford, a program manager in DARPA’s Strategic Technology Office.

Nanoelectrofuel batteries have several advantages over lithium-ion batteries and internal combustion engines for military applications. Protecting a vehicle’s fossil-fuel tank is critical in military fighting vehicles, but the added protection weighs a lot and requires a heavier suspension. Lithium-ion batteries, which are heavy in themselves and prone to fires, would also need to be heavily shielded against a shell hit. By contrast, nanoelectrofuel batteries are fireproof, reducing weight and safety issues tremendously.

Nanoelectrofuels are inherently safe and don’t require as much inner packaging in the battery itself. They also don’t give off as much heat, making the vehicles harder to spot from a distance. Civilian applications for nanoelectrofuel flow batteries are also promising, especially in aviation. The reduced need for fire-safety systems in electric aircraft is a draw, according to Starr Ginn, NASA’s advanced air-mobility lead strategist.

With nanoelectrofuels, high-powered cables and electromagnetic interference problems are eliminated, making it easier to build electric airplanes. The U.S. Air Force Research Laboratory’s Transformational Capabilities Office is assessing how nanoelectrofuels could help in combat operations. Influit is also working with a commercial partner to pilot nanoelectrofuel flow batteries in their line of electric utility vehicles.

In conclusion, nanoelectrofuel flow batteries have the potential to revolutionize the EV market and provide a safer and more efficient alternative to lithium-ion batteries. With ongoing research and development, the cost of nanoelectrofuel is expected to decrease further, making it a more viable option for widespread adoption in the future.

Lithium-ion batteries have a considerable head start

In the race to develop better and more efficient energy storage solutions, nanoelectrofuel flow batteries face significant challenges, including competition from established technologies like lithium-ion batteries. Lithium-ion batteries have a considerable head start in terms of development, with a mature market and significant investment from governments and private companies alike.

Governments around the world, including the US, EU, and South Korea, have invested billions of dollars in lithium-ion battery research and development, with organizations like DARPA, the Department of Energy, and the National Science Foundation working with companies to overcome the limitations of the technology. Meanwhile, private companies are investing heavily in the development and improvement of lithium batteries of all types.

In addition to the significant investment in lithium-ion batteries, there are also new battery chemistries being developed that are not lithium-based, such as sodium-ion and graphene-based batteries. There have also been advances in grid-scale batteries involving liquid metal technology and improved traditional flow-battery technology using lithium sulfur.

Furthermore, there is intense competition within the lithium-ion battery space itself, with new advances being announced regularly. For example, researchers at the Chinese Academy of Sciences have developed a 711 Wh/kg lithium-ion battery, while a Chinese manufacturer claims that a new lithium manganese iron phosphate battery chemistry will power an EV for 1,000 km on a single charge and last 130 years. Other announcements involve significant improvements in rapidly charging lithium-based batteries and making them safer for use in military vehicles.

Given the significant investment and competition in the lithium-ion battery space, Influit Energy, the company behind nanoelectrofuel flow batteries, will need to convince someone with deep pockets to help it scale up. This could come from its own logistics supply chain or from EV manufacturers. In addition, Influit will need to articulate what the “market differentiator” for nanoelectrofuels is in order to gain market adoption. Right now, the technology appears to be a particularly good fit for the Department of Defense, which would likely be willing to pay a premium for it, given that it is the largest user of fossil fuels in government.

Despite the challenges, Influit Energy and its government sponsors are optimistic about the potential of nanoelectrofuel flow batteries. By 2025 or 2026, the world may be ready to seriously consider the technology for powering zero-emission vehicles, grid backup, electric utility vehicles, and other applications. However, considerable work must be done to put together a closed-loop system and prove its value and scalability in a variety of applications. It remains to be seen whether nanoelectrofuels will find a home in other applications, such as boats, trains, or planes, or whether they will be just another example of a superior technology that came too late or too early to displace the incumbents.

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Frequently Asked Questions

What are the Leading Companies in the Redox Flow Battery Market?

The redox flow battery market is highly competitive, with several companies vying for a significant market share. Some of the leading companies in the redox flow battery market include:

Sumitomo Electric Industries
UniEnergy Technologies
Gildemeister Energy Solutions
Redflow Limited
ViZn Energy Systems

What Recent Advancements have been made in Energy Storage Technologies?

Recent advancements in energy storage technologies have focused on improving the performance and efficiency of batteries. Some of the latest developments include:

Solid-state batteries that offer higher energy density and longer cycle life.
Lithium-sulfur batteries that offer higher energy density and lower cost.
Flow batteries that offer higher efficiency and longer cycle life.

How do Flow Batteries Compare to Lithium-Ion Batteries in Terms of Performance?

Flow batteries offer several advantages over lithium-ion batteries in terms of performance. Flow batteries have a longer cycle life, can be charged and discharged simultaneously, and have a higher energy density. However, lithium-ion batteries are more compact and have a higher power density.

Can you Provide an Overview of How Flow Batteries Work, Including a Diagram?

Flow batteries work by storing energy in two separate tanks containing electrolyte solutions. The electrolyte solutions are pumped through a cell stack where the chemical reactions take place, generating electricity. The charged electrolyte solutions are then stored in separate tanks until they are needed to generate electricity again.

What are the Primary Advantages and Disadvantages of Using Flow Batteries for Energy Storage?

The primary advantages of using flow batteries for energy storage include:

Longer cycle life
Higher efficiency
Scalability
Ability to store large amounts of energy

The primary disadvantages of using flow batteries for energy storage include:

Higher cost
Large physical footprint
Lower power density

Are There any New Developments in Membraneless or Hybrid Flow Battery Technology?

Recent developments in flow battery technology have focused on membraneless and hybrid flow battery systems. Membraneless flow batteries eliminate the need for a membrane, reducing the cost and complexity of the system. Hybrid flow batteries combine the advantages of different flow battery chemistries to improve performance and efficiency.