The Components of a Lithium Ion Battery

All rechargeable batteries lose charge over time, but lithium-ion packs tend to last longer than other battery types. Battery life is typically evaluated by cycle count and internal resistance.

Lithium ion is based on the seminal discovery of Goodenough5 that transition metal oxides can reversibly absorb and emit lithium ions. They have high energy density and excellent charge efficiency.

The Electrolyte

The electrolyte is the liquid that conducts lithium ions between the negative electrode and the positive electrode in the battery cell. Its role is crucial for the battery’s performance and safety as it hinders further chemical reactions between the electrodes. In addition, it is responsible for forming the solid electrolyte interphase (SEI) layer that protects the cathode and anode during cycling by preventing the formation of dendrites.

To enhance the properties of the electrolyte and reduce the internal resistance, a variety of additives are used. Vinylene carbonate (VC) is a popular additive in Li batteries because it significantly improves the cycle life of a battery and keeps the internal resistance low with use and age. It also prevents the formation of a thick SEI film on the cathode and increases the cycling stability of the battery.

Ionic liquids (IL) are promising electrolytes for LI-ion batteries because of their high decomposition temperature, non-flammability and low viscosity. Their room temperature ionic conductivity is several times higher than that of aqueous solutions at the same salt concentration. ILs have a wide range of combinations of cations and anions. The most commonly used cations are imidazolium, quaternary ammonium, pyrrolidinium and piperidinium, while the most common anions are BF4-, PF6- and bis(trifluoromethanesulfonyl)imide (TFSI).

A recently developed n-butyl-n-methyl-3-methylimidazolium tetrafluoroborate (BPIM) based IL with the PYR14 backbone has been shown to have excellent cycling performance, rate capability and electrochemical stability. Moreover, its polarity controllability and efficacy against lithium dendrite nucleation and growth have been shown to be very effective.

The Cathode

The cathode is coated with an active material to allow reversible absorption/emission of lithium ions. The cathode plays a significant role in the battery’s voltage. The more lithium ions that can be stored, the higher the battery’s voltage. Currently, most batteries use graphite as the cathode substrate and silicon as the anode substrate. Graphite is the most commonly used anode material due to its low cost, good cycle life, and high energy density. Lithium Ion Battery However, there are many iterations of anode materials and some use a combination of silicon and graphite to enhance performance characteristics.

In addition to storing lithium ions, the cathode is responsible for conducting an electric current during charge and discharge. The process occurs when the external circuit provides electrical energy, causing the anode to lose electrons and the cathode to gain them. This results in a flow of lithium ions from the anode to the cathode, and then vice versa when charging.

In order to do this, the cathode needs to be able to transfer the lithium ions with high efficiency and a fast rate. The chemistry behind this is known as insertion/deintercalation. This is a complex process that involves modifying the surface of the cathode material. This can be done by adding nanoparticles, reducing particle size, or using a more active material. A combination of these changes can significantly increase the battery’s energy densities and cycle life.

The Anode

The anode is a key component of a lithium ion battery, as it plays the role of storing electrons during discharging and transporting them back during charging. The microstructure, texture and crystallinity of anode materials directly influence the electrochemical performance of batteries.

When the battery is charged, lithium ions move from the cathode to the anode through the electrolyte and separator. They do this by insertion or extraction. Insertion is a chemical process where lithium ions absorb into the anode material, whereas extraction is a physical process where the lithium ions pass through the anode material to reach the cathode.

Anode performance is critically important for the overall efficiency of a Li-ion battery as it powers electrification and clean energy, particularly 24V Lithium Iron Phosphate Battery in mobile devices, electric vehicles and grid storage applications. The ability to meet this growing demand relies on breakthroughs in battery anode chemistry.

To achieve high-performance, anode materials must exhibit a wide range of qualities: optimizing specific energy for improved capacity, current handling for higher loading, ruggedness for longevity and safety, and robustness against environmental exposure. Often, an enhancement in one of these areas will lead to the trade-off of another. This is a critical reason why manufacturers need to be able to customize their anode materials and blends to suit the application.

The Battery Pack

Lithium-ion batteries are the cornerstone of the energy transition. They are capable of storing more energy in a lighter package than competing technologies and are used across multiple sectors including mobile phones, electric vehicles, solar panels and hybrid cars. Lithium-ion battery technology has revolutionised the way we use our electronic devices and will continue to do so for years to come.

The battery pack consists of multiple cells integrated together with a BMS (Battery Management System). Verkor manufactures and develops pouch and cylindrical lithium-ion batteries in three form factors to ensure the right size for your application.

Cells are made up of two current collectors – a positive electrode called LiCoO2 or Lithium iron phosphate and a negative electrode called graphite. These are wrapped in a separator and placed in an electrolyte solution. Lithium ions are transported between the cathode and anode by the electrolyte to release free electrons which creates a voltage difference. This power source is the driving force behind every function in your device.

Lithium-ion batteries contain critical minerals like cobalt and graphite. When discarded incorrectly these heavy metals can leak into the environment contaminating surrounding water bodies. They also emit greenhouse gases during charging. It is therefore crucial that you dispose of your battery according to the manufacturer’s instructions or go to an authorized recycling centre.