I was recently interviewed by a Finnish magazine Tekniikan Maailma about end-of-life batteries from electric vehicles and the related need for battery raw materials. This inspired me to write some thoughts here as well. So, what are the options and challenges of recycling and reuse of batteries, and why don’t we use recycled materials in batteries yet?

The biggest bottleneck for using recycled materials in new batteries is that the batteries are still being used in cars! There are not enough used batteries available since their lifetime has been even longer than originally anticipated. This is of course very good, but we need to be also prepared to handle and recycle the batteries as soon as they reach their end of life.

Most of the material, which is currently recycled, comes still from the battery manufacturing scrap. The biggest material amounts from the used EV batteries will reach the recycling factories later. McKinsey estimates that the number of end-of-life batteries, measured in kilotons, will overcome the amount of production scrap around year 2030. After that, we will see a huge growth in the number of end-of-life batteries.

There was recently an excellent article in LinkedIn, by Hans Eric Melin, describing this situation, saying that the battery recycling market is about to experience “the ketchup effect”, which means “first comes nothing and then comes everything”.

Recycling of batteries

There are different ways to recycle batteries. The two main methods are hydrometallurgy and pyrometallurgy, or a combination of them. In addition, direct recycling is being developed as a novel, and more energy and cost-efficient option.

Hydrometallurgy uses aqueous chemistry to dissolve and recover metal salts from the pre-treated battery waste. Its main benefit is the high recovery rate. Pyrometallurgy uses high (>1000°C) temperatures to extract the valuable metals. It is a simpler process but does not recover all metals as well as hydrometallurgy. Often a combination of both methods is used to maximize the yield.

Direct recycling is a promising method as it can enable reduced cost and emissions for the recycling process. Here, the metals are not recovered as elements. Instead, the used cathode active materials, such as NMC (lithium nickel manganese cobalt oxide) or LFP (lithium iron phosphate), are reactivated/relithiated as such.

A nice review of different recycling methods can be found e.g. here. In addition, for more details about direct recycling, you can check e.g. this article.

Reusing of batteries

An EV battery is considered to have reached its end of life in a car when it has 80 % capacity left, compared to the original status. Thus, it can still store energy, even though it is not good enough for a car as the range drops when the capacity decreases. One option to maximize the battery lifetime is to use an old EV battery in a stationary energy storage application.

This makes sense, but not always. Some old batteries contain a lot of critical raw materials, such as NMC111 with ~30 % of cobalt in the cathode active material, which we can utilise in a much better way now than about 10 years ago when the battery was made. Thus, it is good to recycle those batteries fast. For batteries with lower cost and with better available materials, 2nd life use can be a good option. This enables cutting down the carbon dioxide emissions from the production vs. stored kWh during the whole lifetime, which certainly will increase the sustainability.

As the price of new batteries keeps dropping, there is a growing pressure to minimize the cost of 2nd life batteries as well. It can be cheaper and easier to buy a fresh battery, which is originally designed for stationary storage purposes. Testing and analysing the health of a used EV battery takes time and money, and its properties might not match perfectly with the requirements of stationary storage. Here the advanced analysis methods come to help as they will enable estimation of the battery health and will enable choosing the best use for an old EV battery in a safe and cost-efficient way.

So, as usual, there is no one-size-fits-all solution available. 2nd life use can make sense for some old batteries. But especially for batteries that contain a lot of critical raw materials, and for which we have established recycling methods available, fast recycling might be a better option.

Varying battery chemistries and recycling

One of the biggest challenges in battery recycling is that there are several different Li-ion battery chemistries, which might require different recycling processes. We already have quite efficient recycling processes available for the standard NMC/graphite Li-ion batteries. It is also easier to make their recycling profitable as the materials, such as cobalt, have a high value.

There are more challenges with the low-cost materials, which are used e.g. in the LFP batteries. The recycling process must be cost and energy efficient. Otherwise, the primary raw materials will be cheaper than the recycled ones. And as the battery prices are falling globally and the cell manufacturing companies are struggling to be profitable, price of the raw materials is very important.

It will be also expensive to develop and run a different recycling process, potentially with different equipment, for different battery chemistries. Thus, it is essential to develop recycling methods, which can cope with variations in the cell chemistry. This is not easy. Thus, we have added this as a target in the Batt4EU Strategic Research and Innovation Agenda. We should put efforts and funding to research, which can enable development of flexible recycling processes, capable of handling different chemistries, including silicon/graphite anodes, different cathode active materials etc.

What about Na-ion and solid-state batteries?

There are also other types of batteries than Li-ion batteries. Na-ion batteries may have a benefit in recycling, compensating the “challenges” related to their low-cost materials. They can use aluminium as the current collector both at the cathode and anode, which simplifies the recycling process. In Li-ion batteries, we have both copper and aluminium current collectors. In addition, if there are only water-based binders in the cell, which is possible for Na-ion batteries, we do not need to use toxic or harmful solvents in the recycling process. This of course applies also to such Li-ion batteries, which use only water-based binders. However, most of the Li-ion batteries still rely on PVDF as the binder (especially in the cathode), which is not water-soluble. But this will hopefully change in the future and there are several activities ongoing, in research and industry, to fully replace the fluorinated binders with water-soluble ones.

A special case regarding recycling is a solid-state battery. Especially if it contains a metallic lithium anode. Metallic lithium is highly reactive, and it may be a safety risk in the recycling process. Batteries with such anodes should not be fed into a standard mechanical recycling line, where they are crushed, as there might be a risk of explosion or fire. Thus, we need to develop methods, which can either disassemble the cell easily and remove the metallic lithium before further processing, or use a special atmosphere during the crushing, which will prevent lithium to react aggressively.

Investments, education, and research are needed

To summarize, circularity is our only option for building a sustainable and profitable battery industry. This is highlighted clearly in the new Batteries Regulation as well, where the European Commission has set ambitious targets for the recycling efficiency and for the amount of recycled materials in new batteries.

Now is the time to put enough resources for the development of recycling processes, and to educate people to work in this field. When we approach year 2030, we will have an increasing number of end-of-life batteries in our hands. We need to be ready for this. There are already several great examples from the recycling industry and research. So, this is not an impossible task. However, it requires funding both for setting up industrial recycling lines and for the research to develop new, more flexible, safe and energy efficient recycling and pre-treatment processes for the varying battery chemistries.

As there is not yet enough batteries to be recycled, and thus no significant revenue foreseen in the next few years, the industry needs financial support for building the recycling facilities. I hope that the Innovation Fund or other European support mechanisms will enable this. Otherwise, we will see the valuable materials being exported elsewhere, which is a clear risk for the resiliency of Europe.