Researchers develop nano-filtration membrane to help recycle old EV batteries

16-09-2022 | By Robin Mitchell

While EVs are set to be the climate solution to transportation, their reliance on lithium is introducing numerous challenges including skyrocketing lithium prices, restricted lithium production, and the vast environmental damage caused by its extraction. Recently, researchers from Toray Industries announced that it is working on a nano-filtration membrane that will help to extract lithium from old batteries and thus reduce the need for large-scale mining operations. What challenges does lithium present, what have the researchers announced, and how will recycling play a key role in future EVs?

What challenges does lithium face?

As the concerns for climate change continue to increase, the general public is looking toward green technologies to try and reduce the future impacts of rising global temperatures. One solution that seems to be making both the public and governments happy is the introduction of electric vehicles as they do not generate CO2 when in operation and can be charged from renewable energy sources. 

While EVs certainly reduce the number of pollutants emitted in dense residential areas, they are far from being green. The biggest challenge presented by EVs is that they require electricity to operate, which is more often than not generated by fossil fuels such as coal, oil, and gas. Now, it is perfectly possible to charge EVs from renewable energy sources only, but considering that renewables cannot provide grid stability, the inclusion of more EVs will just increase our dependency on fossil fuels (unless nuclear is more heavily adopted).

Another challenge that EVs face is their dependency on lithium for energy storage. Lithium is a particularly troublesome mineral to mine as it requires thousands of acres of evaporation pools containing concentrated toxic minerals that devastate local environments and potentially pollute groundwater. At the same time, current EV batteries are not easily recycled, and this can see large amounts of toxic waste generated at landfills which further destroy the environment. Thus, EVs are being adopted with the idea of protecting the climate while simultaneously destroying the very environment we are trying to save.

Toray Industries developing nano-filtration membranes

Compounds found in lithium batteries can be dissolved with the use of acidic compounds, but such acidic solutions typically destroy most membranes needed to extract the lithium. As such, lithium extraction from EVs has historically been uneconomical.     

Recognising the challenges faced by EVs and lithium recycling, Toray Industries recently announced the development of nano-filtration membranes with precision pour structures smaller than 1nm. The membrane is constructed from a cross-linked polymer manufactured with the use of organic synthesis, polymer chemistry, and nanotechnology. The researchers have developed the ability to selectively extract lithium from high acidic solutions with a selectivity of greater than 50%. 

One of the major advantages of the Toray Industries membrane is that by current calculations, their method for extracting 1KG of lithium results in 2/3 of the CO2 generated from raw ore extraction, and eliminates the need for evaporation pools. Furthermore, Toray Industries announced that it collaborate with automakers and battery manufacturers to help encourage battery recycling technologies.

How will recycling play a key role in future EVs?

When considering the amount of environmental damage caused by EVs, it makes sense that recycling will play a critical role in their future. Even though combustion engines release CO2, the environmental damage they cause is significantly less than EVs due to the use of basic materials such as aluminium and steel. Furthermore, combustion engines can also run off green fuels, effectively eliminating their carbon footprint.

At the same time, EVs face a major threat from hydrogen power as hydrogen power not only provides better energy density, but it is not dependent on huge quantities of toxic materials. In fact, it is most likely that larger vehicles (such as trucks and lorries) will move towards hydrogen thanks to the better weight-to-cost ratio of hydrogen (EVs will never enter the haulage industry because of this issue). 

If the purpose of EVs is to provide the world with a green solution, it should do so on all fronts, not just the facade of zero CO2 when driving from point A to point B. In fact, it might be time that the concept of carbon footprints are scrapped in favour of a more environmentally considered footprint which accounts for land use, pollutants released, and deaths associated with that industry.