The everyday relevance of batteries continues to increase.
The average person meets batteries hundreds of times per day, because battery technologies are used for almost everything nowadays. In day-to-day life you may encounter them in common gadgets like cellphones, laptops and electric vehicles (EV). But there are also more extravagant applications like electric ships or rovers on Mars.
A quick look at Google trends reveals that search terms involving “Lithium” have gained significant momentum. Over the past years, there has been an increased level of reporting in mainstream media about the scarcity of materials needed for as well as almost weekly announcements of plans for new Giga factories.
Source: Google Search Trends for Lithium
Until 2030, less than 10 years away, the lithium battery production capacity in Europe is forecasted to increase to 950GWh per year (production capacity in 2020: 60GWh). With this amount of energy, an average electric vehicle would carry you 6,365,000,000 kilometers – or 233 times to Mars and back. These forecasts are backed by announcements made by battery cell producers and automotive companies. The map below shows the aggregated capacity from some projects that will be realized in the following years in each country to prepare for the increasing demand.
Major automotive manufacturers have seen the need to take more control over their value chains.
Tesla has been a pioneer by collaborating with Panasonic in building the first Gigafactory in Nevada, USA, already at an early stage. But other car companies are catching up. VW for example wants to open six giga factories in Europe. They intend to “drive down the cost of battery systems to significantly below €100 per kilowatt hour on average”.[1] According to the laws of economies of scale, the price will depend mainly on raw materials in the long run. However, if they succeed, these costs would still sum to 95 billion € annually, if we keep in mind the 950GWh which will be needed from 2030 onwards.
Batteries work due to the (complex) interplay of different chemical raw materials.
Li-Ion Batteries are based on the principle of storing chemical energy and converting it into electrical energy when needed. The conversion takes place by exchanging positively charged Lithium atoms (called Ions) internally and negatively charged electrons externally between two electrodes. It is a process of reaching an equilibrium. Because, if charges move from one side to another the difference must be compensated. The flow of electrons is what we commonly call electricity.
Flow of electrons and Li-Ions when the battery is discharged. The direction is reversed when the battery is recharged by an external power source. Source: Battery basics – An introduction to the science of lithium-ion batteries, Billy Wu, Dyson School of Design Engineering, Imperial College London, 2020
Electrodes can be seen as storage containers in which the positive charges are stocked (intercalation) and held in place by the general structure of the material in combination with the attracting power of electrons. Each electrode has different storage capabilities like speed and quantity of ion storage and how well electrons are conducted. They are referred to as Anode and Cathode and are the most critical elements of a battery since they determine the size and weight, capacity, speed of charging, lifetime and safety and of course the costs.
Battery producers face the challenge of enhancing specific attributes without sacrificing performance in other areas.
For the anode, a standard has been established with the usage of graphite – which offers a good tradeoff between cost and performance. Graphite consists of single layers of plain carbon atoms that are assembled in a hexagonally structured mesh. (Btw- it is also what our CheMondis logo is inspired by.)
Source: DOI:10.1109/MTDT.1999.782691
These layers perfectly offer space for Li-Ions to be intercalated between them. Additionally, graphite shows good conductivity for electrons.
The cathode on the other side gives more potential for optimization. The search for the perfect cathode can be summarized in the following radar chart. And the moment, cathode materials based on Nickel-Manganese-Cobalt (NMC) or Nickel-Manganese-Aluminum (NCA) seem to offer the best tradeoffs but are subjects of ongoing research. The content of each metal can be varied. Nickel affects capacity, cobalt influences stability and manganese contributes to safety and cost.
Source: Battery basics – An introduction to the science of lithium-ion batteries, Billy Wu, Dyson School of Design Engineering, Imperial College London, 2020
Another crucial aspect of battery performance, lifetime and safety is the medium through which the exchange of ions is fulfilled. This medium is referred to as Electrolyte and consists of Li-Ions that are solved and stabilized by a solvent as well as various additives. There are some critical requirements these electrolytes need to fulfill. They need to be chemically and thermally stable, highly conductive and need to show low procurement cost.
The current state of the art technology (as applied by many car manufactures like Tesla, Chevrolet, Hyundai) uses liquid electrolytes since they offer good mobility for ions but come with increased safety hazards because the solvents are usually highly flammable. Typical solvents are Ethylene carbonate and Dimethyl carbonate in which salts of Lithium ions (mostly LiPF6) are added. Fluoroethylene carbonate is used as an effective additive to enhance the batteries’ stability.
The raw materials are finely ground, combined with a polymeric binder and then coated onto a conducting substrate. They are rolled to a cylindrical cell, filled with electrolyte and connected with copper to close the circuits. Up to 4000 of these cells are combined to battery systems in each car.
It becomes apparent that Li-Ion batteries consist of various chemicals. Consequently, pure Lithium makes up only 13% of the batteries mass (in case of a Tesla Model S with 70KWh of battery capacity). The graphite used for the anode accounts for 22%, Copper and Aluminum for transporting the electrons to the external part of the circuit make 25% and even the electrolyte solution contributes 15%. The following diagram shows the distribution of each compound.
So, let’s play a little game. What would you need to buy & assemble to achieve the 950 GWh of capacity creation?
Based on the rough sketch of a battery’s composition, we can start to make our calculation. You would need:
Annual demand for creating 950GWh of electricity based on current battery technology. Source: Jacoby, M. (2019). It’s time to get serious about recycling lithium-ion batteries. C&en Chemical & Engineering News
What development can we expect in the future?
The electronic vehicle (EV) market has started to grow exponentially. However, electronic equipment is still by far the major market for lithium-ion batteries. The huge demand from end users will translate to a voluminous extraction of resources along the value chain and is afflicted with various environmental and social issues.
The World Bank has estimated in a 2020 report that five times more lithium than mined today will be necessary to meet global climate targets by 2050.
At present, Lithium is sourced mainly from hard rock mines (e.g. in Australia) or underground brine reservoirs below the surface of dried lake beds (mostly Chile and Argentina). The current sourcing practices account for an extensive usage of water of up to 500,000 liters per ton of lithium and huge CO2 emissions (up 15 tons per ton of Lithium). Therefore, new extraction methods are being developed and applied. Geothermal waters, found in the US and even UK or Germany, offer a source of lithium with greatly reduced environmental impact. These waters have circulated through extremely hot rocks and have become enriched with elements like lithium, boron and potassium. The energy intensive process of extracting lithium from rocks is powered by natural available geothermal energy.
Some sources conclude that the demand for cobalt is expected to grow even higher by a factor of 10 to 20. Cobalt is a toxic, heavy and expensive element that is linked to unethical mining practices including child labor. Furthermore, two third of the cobalt production is taking place in the Democratic Republic of Congo which poses a significant supply dependence on one single region. To eliminate and mitigate risks, new technologies with different chemistries are constantly being researched. LG Energy solutions has developed a battery technology (NCMA) that uses less cobalt and a higher concentration of nickel (90%) which will be used in future Tesla’s and cars from General Motors. Current research also indicates that cell technology which has completely renounced lithium and cobalt and is based on Sulphur or Oxygen shows great potential.
The third area of innovation lies in the electrolyte chemistry. Liquid electrolytes are based on solvents that are highly flammable and can cause the battery cells to explode when electrode materials corrode after extensive usage. So-called solid-state electrolytes offer more safety because they use highly engineered polymeric materials that don’t need liquid components. Volkswagen entered a cooperation with QuantumScape, a company specialized in the development of solid-state batteries, already in 2012. After the company went public on the New York Stock Exchange recently, they announced that the first products will be available in 2024.
Another crucial aspect of clean energy programs is the recycling of batteries. At the moment the number of end-of-life electric-vehicle batteries is still low. But the amount will grow exponentially in the coming years and demands for efficient recycling strategies increase. As batteries that have lost substantial capacity need to be replaced in electric vehicles, they find in a second life in residential energy storage facilities to balance swings in local electrical grids. However, all materials mentioned before still have value and can also be recovered and reused for new battery production. Several research programs are in place – the co-founder of Tesla, JB Straubel, has already founded a new company that specializes in reusing materials from Li-Ion batteries.
The future will bring a vast array of different technologies and chemistries. It makes sense to source for new suppliers and new formulations for the upcoming supply bottlenecks.
Thanks for taking the time to read the CheMondis blog.
Sources:
- [1] CNBC (2021). VW to ramp up battery cell production with six ‘gigafactories’ in Europe.
- CNC Energi Gune. Gigafactories: Europe’s major commitment to economic recovery through the development of battery factories.
- Wu, B. (2020). Battery basics – An introduction to the science of lithium-ion batteries.
- CNBC (2021). VW to ramp up battery cell production with six ‘gigafactories’ in Europe.
- Helbig, C., Bradshaw, A., Wietschel, L., Thorenz, A., Tuma, A. (2018). Supply risks associated with lithium-ion battery materials.
- Van den Brink, S., Kleijn,R., Sprecher, B., Tukker, A. (2020). Identifying supply risks by mapping the cobalt supply chain. Resources, Conservation and Recycling, Volume 156.
- BBC. (2020). The new ‘gold rush’ for green lithium.
- Hund, K., La Porta, D., Fabregas, T., Laing, T., Drexhage, J. (2020). Minerals for Climate Action: The Mineral Intensity of the Clean Energy Transition.
- Jacoby, M. (2019). It’s time to get serious about recycling lithium-ion batteries. C&en Chemical & Engineering News.
- Lambert, F. (2021). Tesla is expected to be first to use LG’s new NCMA nickel-based battery cells.
- Korosec, K. (2020). Volkswagen-backed QuantumScape to go public via SPAC to bring solid-state batteries to EVs.
