Week 1 Understanding Different Battery Chemistry
Objective -
- To prepare a table which includes materials & chemical reactions occurring at the anode and cathode of LCO, LMO, NCA, NMC, LFP and LTO type of lithium ion cells.
- To compare the differences between each type of Li+ion batteries based on their characteristics
Theory -
Lithium Ion Battery -
- A lithium-ion battery or Li-ion battery is a type of rechargeable battery composed of cells in which lithium ions move from the negative electrode through an electrolyte to the positive electrode during discharge and back when charging.
- Li-ion cells use an intercalated lithium compound as the material at the positive electrode and typically graphite at the negative electrode.
- Li-ion batteries have a high energy density, no memory effect (other than LFP cells) and low self-discharge.
- Cells can be manufactured to prioritize either energy or power density.
- They can however be a safety hazard since they contain flammable electrolytes and if damaged or incorrectly charged can lead to explosions and fires.
Types of Lithium Ion Battery -
- Lithium-ion batteries come in a variety of shapes and sizes, and not all of them are made equal.
- Below are descriptions of six different lithium-ion battery types, as well as their compositions and common applications.
- Lithium Cobalt Oxide (LCO) -
- Lithium cobalt oxide batteries are manufactured from lithium carbonate and cobalt and are also known as lithium cobaltate or lithium-ion cobalt batteries.
- These batteries are used in cell phones, laptops, and electronic cameras because of their high specific energy.
- They have a cobalt oxide cathode and a graphite carbon anode, and lithium ions migrate from the anode to the cathode during discharge, with the flow reversing when the battery is charged.
- They are a popular choice for cell phones and other portable electronic devices.
- Chemical Reactions
For Anode, `Li_nC_6` ⇌ `Li_0C_6 + nLi^+ + n e^-`
For Cathode, `Li(m-n)CoO_2 +nLi^+ + n e^-` ⇌ `Li_mCoO_2`
Overall Reaction, `Li_nC_6 + Li_(m-n)CoO_2` ⇌ `Li_0C_6 + Li_mCoO_2`
- Lithium Manganese Oxide (LMO)-
- Lithium manganese oxide batteries are sometimes known as lithium manganate or lithium-ion manganese batteries, or li-manganese or manganese spinel batteries.
- High-temperature stability distinguishes lithium manganese oxide batteries from others, which are also safer than other lithium-ion battery types.
- As a result, they’re frequently found in medical equipment and devices, but they can also be used in power tools, electric motorcycles, and other applications.
- Lithium manganese oxide batteries can also be used to power laptop computers and electric vehicles.
- Chemical Reactions
For Anode, `Li_nC_6` ⇌ `Li_0C_6 + nLi^+ + n e^-`
For Cathode, `Li_(m-n)Mn_2O_4 +nLi^+ + n e^-` ⇌ `Li_mMn_2O_4`
Overall Reaction, `Li_nC_6 + Li_(m-n)Mn_2O_4` ⇌ `Li_0C_6 +Li_mMn_2O_4`
- Lithium Iron Phosphate (LFP)-
- Phosphate is used as a cathode in lithium iron phosphate batteries, often known as li-phosphate batteries.
- They have low resistance qualities, which improve their thermal stability and safety.
- When the lengthy battery life of Li-phosphate batteries is considered, they are frequently the most cost-effective option.
- These batteries are frequently used in electric bikes and other applications requiring a long lifecycle and high levels of safety.
- These batteries are also commonly used in electric vehicles.
- Chemical Reactions
For Anode, `Li_nC_6` ⇌ `Li_0C_6 + nLi^+ + n e^-`
For Cathode, `Li_(m-n)FePO_4 +nLi^+ + n e^-` ⇌ `Li_mFePO_4`
Overall Reaction, `Li_nC_6 + Li_(m-n)FePO_4` ⇌ `Li_0C_6 +Li_mFePO_4`
- Lithium Nickel Manganese Cobalt Oxide (NMC) -
- Lithium Nickel manganese Cobalt Oxide batteries, often known as NMC batteries, are constructed of a variety of materials that are universal in lithium-ion batteries.
- A cathode constructed of a mix of nickel, manganese, and cobalt is included.
- NMC batteries, like other lithium-ion battery types, can have a high specific energy density or a high specific power.
- This battery is most commonly seen in power tools and automobile powertrains.
- 60% nickel, 20% manganese, and 20% cobalt are commonly the cathode combination ratios.
- Because of its low self-heating rate, this battery type is often used in electric vehicles.
- Chemical Reactions
For Anode, `Li_nC_6` ⇌ `Li_0C_6 + nLi^+ + n e^-`
For Cathode, `Li_(m-n)(Ni_xMn_yCo_z)O_2 +nLi^+ + n e^-` ⇌ `Li_m(Ni_xMn_yCo_z)O_2`
Overall Reaction, `Li_nC_6 + Li_(m-n)(Ni_xMn_yCo_z)O_2` ⇌ `Li_0C_6 + Li_m(Ni_xMn_yCo_z)O_2`
- Lithium Nickel Cobalt Aluminum Oxide (NCA) -
- NCA batteries, or lithium nickel cobalt aluminum oxide batteries, are making their way in electric vehicles and grid storage.
- NCA batteries offer a high-energy choice with a long lifespan, but they are less safe than other lithium-ion battery types and are rather expensive.
- NCA batteries are used in electric vehicle with monitoring systems.
- Chemical Reactions
For Anode, `Li_nC_6` ⇌ `Li_0C_6 + nLi^+ + n e^-`
For Cathode, `Li_(m-n)(Ni_xCo_yAl_z)O_2 +nLi^+ + n e^-` ⇌ `Li_m(Ni_xCo_yAl_z)O_2`
Overall Reaction, `Li_nC_6 + Li_(m-n)(Ni_xCo_yAl_z)O_2` ⇌ `Li_0C_6 + Li_m(Ni_xCo_yAl_z)O_2`
- Lithium Titanate (LTO) -
- Lithium titanate, often known as li-titanate, is a type of battery that has a growing number of uses.
- Because of its superior nanotechnology, the lithium-titanate battery has an extremely rapid recharge time.
- Li-titanate batteries are being employed by makers of electric vehicles and bicycles, and this type of battery has the potential to be used in electric buses for public transit.
- Lithium titanate batteries have a higher density than non-lithium-ion batteries.
- These batteries could be used for military and aerospace applications, as well as storing wind and solar energy and constructing smart grids.
- Chemical Reactions
For Anode, `Li_2TiO_3` ⇌ `TiO + O_2 + 2Li^+ + 2e^-`
For Cathode, `Li_(n-2)Mn_2O_4 + 2Li^+ + 2e^-` ⇌ `Li_nMn_2O_4`
Overall Reaction, `Li_2TiO_3 + 2 Mn_2O_4` ⇌ `2LiMn_2O_4 + TiO + O_2`
| Type Of Lithium Ion Cell | Cathode Material | Anode Material |
Chemical Reactions |
| LCO | Lithium Cobalt Oxide |
Graphite |
`Li_nC_6 + Li_(m-n)CoO_2` ⇌ `Li_0C_6 + Li_mCoO_2` |
| LMO | Lithium Manganese Oxide |
Graphite |
`Li_nC_6 + Li_(m-n)Mn_2O_4` ⇌ `Li_0C_6 +Li_mMn_2O_4` |
| LFP | Lithium Iron Phosphate |
Graphite |
`Li_nC_6 + Li_(m-n)FePO_4` ⇌ `Li_0C_6 +Li_mFePO_4` |
| NMC | Nickel Manganese Cobalt |
Graphite |
`Li_nC_6 + Li_(m-n)(Ni_xMn_yCo_z)O_2` ⇌ `Li_0C_6 + Li_m(Ni_xMn_yCo_z)O_2` |
| NCA | Nickel Cobalt Aluminium |
Graphite |
`Li_nC_6 + Li_(m-n)(Ni_xCo_yAl_z)O_2` ⇌ `Li_0C_6 + Li_m(Ni_xCo_yAl_z)O_2` |
| LTO | Manganese Oxide |
Titanate |
`Li_2TiO_3 + 2 Mn_2O_4` ⇌ `2LiMn_2O_4 + TiO + O_2` |
Differences between each type of Li+ion batteries based on their characteristics
- Specific energy - This defines the battery capacity in weight (Wh/kg). The capacity relates to the runtime. Products requiring long runtimes at moderate load are optimized for high specific energy.
- Specific power - It's the ability to deliver a high current and indicates loading capability. Batteries for power tools are made for high specific power and come with a reduced specific energy.
- Performance - This measures how well the battery works over a wide range of temperatures. Most batteries are sensitive to heat and cold and require climate control. Heat reduces life, and cold lowers performance temporarily.
- Lifespan - This reflects cycle life and longevity and is related to factors such as temperature, depth of discharge, and load. Hot climates accelerate capacity loss. Cobalt blended lithium-ion batteries also usually have a graphite anode that limits the cycle life.
- Safety - This relates to factors such as the thermal stability of the materials used in the batteries. The materials should have the ability to sustain high temperatures before becoming unstable. Instability can lead to thermal runaway in which flaming gases are vented. Fully charging the battery and keeping it beyond the designated age reduces safety.
- Cost - Demand for electric vehicles has generally been lower than anticipated and this is mainly due to the cost of lithium-ion batteries. Hence cost is a huge factor when selecting the type of lithium-ion battery.
|
Li+ ion Battery types |
Specific Power | Specific Energy | Safety | LifeSpan | Cost | Performance |
| LCO | Low | High | Low | Low | Low | Medium |
| LMO | Medium | Medium | Medium | Low | Low | Low |
| NMC | Medium | High | Medium | Medium | Low | Medium |
| LFP | High | Low | High | High | Low | Medium |
| NCA | Medium | High | Low | Medium | Medium | Medium |
| LTO | Medium | Low | High | High | High | High |