Recycling of Lithium-Ion Batteries. How Can Electric Vehicle Batteries Save Valuable Resources Instead of Becoming a Disaster?
As electric vehicles become more and more popular, it makes people worry about their recycling. Their lithium-ion batteries can quickly litter all the landfills. Moreover, they are flammable: one puncture is enough to cause a fire. The good news is that this problem is being solved. Let’s take a look at how it is possible to prevent EV batteries from becoming a disaster.
Solution 1. Reuse
When the battery shows only 80% of its original performance or even less, it can’t be used in an electric vehicle anymore. However, it doesn’t mean that you should contact a recycling firm immediately. A retired battery may well live a second life. It is still able to store energy. McKinsey expects that the second-life battery supply from lithium could surpass 200 gigawatt-hours per year by 2030. Lithium-ion batteries may become a valuable resource for energy storage. Yet, repurposing them is not as easy as it may seem.
There are several challenges businesses face when giving retired batteries a second chance.
1. Too many standards. Every automaker has its standards for manufacturing EV batteries. They vary in size, electrode chemistry, and format (cylindrical, prismatic, and pouch). McKinsey estimates that up to 250 new EV models will exist by 2025, installing batteries from more than 15 manufacturers. Sure, customers will be happy to have such a wide choice but it will make reuse a tough task.
2. Falling costs for new batteries. The cheaper new batteries become, the less the cost difference between used and new ones. This cost gap is expected to drop to around 25 percent by 2040, McKinsey says. It should remain big enough to justify the reuse of lithium-ion batteries.
3. Nascency of second-life-battery standards. There are no standard performance specifications for second-life batteries as well as no guarantees about the batteries’ quality or performance.
4. Immature regulatory regime. While countries regulate mostly the recycling of consumer electronics in general, there are only a few examples of EV-battery-specific requirements or delineations of responsibility between the producer and the consumer.
These challenges are significant but not undefeatable. Collaboration between suppliers, end-users, and regulators in the sector can help a sustainable second-life battery industry to emerge. Some automakers have already taken measures. For example, Nissan partners with Sumitomo Corporation to reuse battery packs from the Nissan Leaf for stationary distributed and utility-scale storage systems. In October 2020, Renault Group presented two energy storage projects that use second-life battery technologies: Advanced Battery Storage (ABS) in Douai (France) and SmartHubs in West Sussex, UK. With other manufacturers following the example, re-usage may become more widespread and reduce the amount of e-waste that, in turn, means saving more natural resources.
Solution 2. Recycling
However, batteries aren’t immortal. Sooner or later, they have to be recycled. Lithium and other metals they contain can seriously pollute our environment and cause risks for our health. Moreover, as demand for these metals increases, the recycling of batteries becomes profitable. Here are different technologies for recycling lithium-ion batteries.
Pyrometallurgical Recovery
Batteries are smelt in a high-temperature furnace. In the process, metal oxide components are turned into an alloy of Co, Cu, Fe, and Ni. At lower temperatures (<150 °C) electrolyte and binding components of batteries evaporate and create gasses. As the temperature rises, the polymers decompose and burn off. In the end, we have slag that contains aluminum, manganese, and lithium as well as a metal alloy. There are two ways we can use this slag. We can reclaim the metals from it via hydrometallurgy or we can use it in other industries such as the cement industry.
Physical Materials Separation
This method is used for reclamation after comminution. Since the batteries are made of different materials with different properties, we can use different devices to separate the materials: sieves, filters, magnets, shaker tables, and heavy media. It allows us to separate a lithium-rich solution, plastics and papers, magnetic casings, coated electrodes, and electrode powders.
Hydrometallurgical Metals Reclamation
Here we get the desired metals by extracting them with the help of aqueous solutions from the cathode material. The most common combination of reagents is H2SO4/H2O2 (Sulfuric acid/Hydrogen peroxide). Hydrogen peroxide acts as a reducing agent that allows converting insoluble materials into soluble ones. In the beginning, the acid dissolves the solid material. After that, we have a leached solution that can be used for extracting metals through a precipitation reaction. At the end of the process, we have lithium and cobalt sulfates, water, and oxygen. Other combinations of reagents make it possible to get the lithium carbonate, lithium phosphate, or water-soluble salts of cobalt. All these substances can be used in various fields as well as for resynthesizing the original cathode materials.
Direct Recycling
It’s also possible to remove cathode or anode material from the electrode and reuse it in a remanufactured battery. This is direct recycling. In this case, lithium content has to be replenished because of degradation of the material in spent batteries and because it is hard to recover materials from batteries in the fully discharged state with the cathodes fully lithiated. This method can be very efficient for some electrodes. For instance, direct recycling or lithium cobalt oxide cathodes via pyrometallurgy or hydrometallurgy can recover around 70% of the cathode value.
Solid-State Batteries as an Alternative
With electric cars becoming more popular, battery makers look for an alternative. Solid-state batteries may well replace lithium-ion ones as they have several advantages. For instance, the solid electrolyte slows the growth of dendrites — crystals that can cause short-circuiting and lead to dangerous explosions. Also, these batteries can operate at extreme temperatures and have higher energy density so manufacturers can use them for a wide range of devices — from medical devices to electric vehicles. Furthermore, solid-state batteries are lighter and smaller than their lithium-ion cousins so they will take less space both in a device and in a landfill. And last but not least, these batteries can be produced from eco-friendly and cheaper materials such as sodium making them a good alternative both for recyclers and battery makers.
However, this alternative has some disadvantages as well. First, the solid electrolyte and electrodes have to be even across their entire surface. Any warping can cause gaps that limit cell efficiency. Another problem is that the electrolyte’s material is brittle. It leads to microscopic fractures that limit cell performance. These disadvantages make solid-state batteries hard to use in electric vehicles — at least, in the next five years or more. But it doesn’t prevent them from spreading in other areas.
As you can see, reusing and recycling lithium-ion batteries is possible. Moreover, it may well become a profitable business as it allows recovery of such valuable materials as lithium, cobalt that are going to be in a short supply. And last but not least, these batteries may well be replaced with a better alternative in the future.
