Cathode Materials for Lithium-ion Batteries
Jump to: Cathode Active Materials | Conductive Additives | Cathode Binders | Current Collector
Cathode materials in lithium-ion batteries (LIBs) are engineered for both exceptional electrical conductivity and long-term stability. The main component of the LIB system is the cathode active material, which serves as the primary source of lithium ions and drives the charge and discharge cycles. To optimize performance, additional components are integrated to boost ionic and electronic conductivity while reinforcing the structural integrity of the electrode.
Cathode Active Materials
Lithium-ion battery performance is heavily influenced by the choice of cathode active material. This selection determines key battery characteristics such as energy density, power output, lifespan, safety, and cost. Cathode active materials are typically classified by their crystal structures: layered, spinel, or olivine, each offering distinct electrochemical properties and advantages. Structural types, compositions, and performance attributes of common cathode active materials are briefly summarized below:
Layered Structure
Layered Structure
Layered Structure
Layered Structure
LCO offers excellent specific energy and performance at a low cost.
NMC811 has excellent specific energy, specific power, safety, performance, lifespan and is low cost.
NMC523 combines high energy density, affordability, low toxicity, stable cycling, and safety.
NCA provides high specific energy and power, with strong performance and long lifespan.
Spinel Structure
Spinel Structure
Olivine Structure
Olivine Structure
LMO provides high specific energy and power, along with superior safety and cost-effectiveness.
LNMO has nickel to enhance specific theoretical capacity and energy density.
LFP, a phosphate-based metal crystal, offers exceptional specific power, safety, performance, and long life cycle.
Manganese doping of LFP increases the battery operating voltage for increased energy density and cycling stability.
Cathode Active Materials
Conductive Additives
Conductive additives play a significant role in enhancing the performance of cathodes in lithium-ion batteries by improving their electrical conductivity. Many of the cathode active materials mentioned above have relatively poor intrinsic electrical conductivity. By adding conductive additives to electrode mixtures, a conductive network forms through the cathode to ensure efficient electron movement. This network helps to distribute the current evenly throughout the electrode, minimizing localized overcharging. They also promote the full use of the cathode active material and reduce the interfacial resistance between it and the current collector.
Common Conductive Additives
Cathode Binders
Cathode binders play an important role in extending the overall lifespan of batteries by protecting electrode integrity. As well as ensuring constant connection between the cathode active material and current collector. The selection of an appropriate binder depends on the crystal structure of the cathode active material. Other essential binder properties include electrochemical, thermal and dispersion stability, compatibility with electrolytes, solubility in solvent, attractive mechanical properties and excellent conductivity.
As current design strategies to increase battery energy density is to increase cathode thickness binders are used to protect from issues such as electrode cracking and flaking during the fabrication process. They also contribute to increasing ionic transfer rates and improving electrode stability over repeated cycling.
Current Collector
Aluminum Foils
Aluminum foil is commercially used as the current collector for secondary Li-ion batteries. This is due to the combination of chemical stability, attractive electrical properties and cost-effectiveness. As the cathode of a lithium-ion battery operates as high voltages (3-5 V vs. Li/Li+) it is important that the current collector remains stable. Aluminum does not easily oxidize or corrode under these conditions and therefore is an ideal candidate. With high electrical conductivity at low density, it minimizes energy loss and overall battery weight. Aluminum foil can be easily rolled, coated and calendared whilst also being cheap and widely available.
Learn More
What is a Ternary Lithium Battery?
A ternary lithium battery is a type of lithium-ion battery (LIB) that has a cathode composed of three different metals. The metals are nickel (Ni), cobalt (Co), manganese (Mn) or aluminium (Al).
Read more...
What is an LFP Battery?
An LFP battery gets its name from it’s key material component, lithium iron phosphate powder, which has the chemical formula LiFePO4. It is also known as lithium ferro phosphate which gets shortened to LFP, hence the name.
Learn more...
References
- Polymeric Binder Design for Sustainable Lithium-Ion Battery Chemistry, Yoon, J. et al., polymers (2024)
Contributors
Written by
Application Scientist
Diagrams by
Graphic Designer