Lithium-ion batteries power our commonly used electronic devices. Several challenges existwith the use of cobalt, a critical component of their cathodes. In thisarticle, we explore how the batteries work, the challenges of using cobalt inthem, and promising new alternatives to cobalt.
How do Lithium-ion Batteries Work?
Lithium-ion batteries are commonly used in a variety of electronic devices. Lithium-ionbattery cathodes are a critical component of the battery. They store andrelease lithium ions during the charging and discharging process. The cathodeis typically made from a material that can reversibly intercalate anddeintercalate lithium ions, such as in lithium cobalt oxide (LiCoO2) or lithiumiron phosphate (LiFePO4).
During charging, lithium ions are transferred from the anode to the cathode, wherethey are stored within the cathode material. When the battery is discharged,the lithium ions are released from the cathode and move back to the anodethrough the electrolyte, generating electricity.
The performance and durability of a lithium-ion battery are heavily dependent onthe properties of the cathode material. Different cathode materials havedifferent electrochemical properties and can provide different levels ofcapacity and energy density.Limitationsof Cobalt as a Cathode Material in Li-ion Batteries.
Recent developments in battery technology have focused on the search for new materialsthat can replace traditional cathode materials, such as cobalt, in lithium-ionbatteries. Cobalt has been widely used in lithium-ion batteries due to its highcapacity and good electrochemical performance.
However,the demand for cobalt has risen sharply in recent years, driven by the growthof electric vehicles and consumer electronics. This has led to an increase inthe price of cobalt, making it a significant cost factor in the production oflithium-ion batteries. In addition, the mining of cobalt often involvesenvironmentally damaging practices and is associated with human rights abuses.
This high cost and limited supply of cobalt have fuelled the need to investigatealternative materials that can provide similar performance without relying onscarce and expensive resources. As a result, cathodes are the focus of ongoingresearch and development efforts to improve the performance and sustainabilityof lithium-ion batteries.
Novel Alternatives to Cobalt as Cathode Materials
One approach to reducing cobalt content in lithium-ion batteries is to usealternative cathode materials. For example, researchers have explored the useof lithium-manganese-oxide (LMO) and lithium-nickel-manganese-cobalt-oxide(NMC) cathodes, which can provide similar performance to traditionalcobalt-based cathodes while using less cobalt.
Other approaches consider the total replacement of cobalt in the cathode. Onepotential replacement for cobalt is nickel. Nickel-based lithium-ion batterieshave been shown to have a higher energy density than cobalt-based batteries,which means they can store more energy in a smaller space. This could lead tothe development of smaller and more efficient batteries.
Another alternative to cobalt is manganese, which has been used in lithium-ionbatteries for many years. Manganese-based batteries are less expensive toproduce than cobalt-based batteries and are also less toxic to the environment.However, they have a lower energy density than cobalt-based batteries, whichmeans they may not be as suitable for use in high-power applications.
Researchers are also investigating the use of lithium iron phosphate (LFP) in lithium-ionbatteries. LFP batteries are non-toxic and more stable than other lithium-ionbattery chemistries, making them safer to use. They also have a longer lifespanthan other lithium-ion batteries and are less likely to catch fire.
However,more recently, researchers at the Department of Energy's Oak Ridge NationalLaboratory have developed a new method for producing a key component oflithium-ion batteries. The researchers report in the Journal of Power Sourcesthat they have developed a cleaner, cheaper, more efficient method for making anew class of high-capacity cathode material without cobalt made of nickel,manganese, and aluminum (LiNi0.9Mn0.05Al0.05O2 (NMA9055)).
The new method is faster, less wasteful, and uses less toxic material, meaning itis more affordable than the traditional process. The new method, hydrothermalsynthesis, crystalizes the cathode using metals dissolved in ethanol. This ismuch faster than the traditional process and is safer to handle and store. Theresulting material has more tightly packed, uniform, and round particles thatmake it ideal for a cathode.
Instead of continuously stirring cathode materials with chemicals in a reactor, theirhydrothermal synthesis approach crystallizes the cathode using metals dissolvedin ethanol. Ethanol is safer to store and handle than ammonia, and afterward,it can be distilled and reused. The researchers are optimistic that the processwill move the cathode industry toward cleaner, more cost-competitive productionwhile putting less strain on our environment.
Conclusions and Outlook
The complete elimination of cobalt from lithium-ion batteries is a complex andongoing challenge. It will require the development of new materials andtechnologies, as well as significant investment in research and development.The potential benefits in terms of cost savings, environmental protection, andsustainability make it an important area of study.
The use of alternative materials in lithium-ion batteries has the potential toreduce the environmental impact of battery production and improve workingconditions in the mining industry. However, it is important to carefullyconsider the trade-offs between different materials, as some may be moresuitable for certain applications than others.
Overall,the development of alternative materials for use in lithium-ion batteries ispromising and could have significant benefits for both the environment and thebattery manufacturing industry.