Week 1 Understanding Different Battery Chemistry

Different Li-ion Battery Chemistry

AIM

• 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. Compare the differences between each type of Li-ion batteries based on their characteristics

BATTERY

• A battery is a device that is able to store electrical energy in the form of chemical energy, and convert that energy into electricity.
• When a battery is supplying electric power, its positive terminal is the cathode and its negative terminal is the anode. The terminal marked negative is the source of electrons that will flow through an external electric circuit to the positive terminal.
• When a battery is connected to an external electric load, a redox reaction converts high-energy reactants to lower-energy products, and the free-energy difference is delivered to the external circuit as electrical energy.

Types

• Primary Battery: Primary cells are non-rechargeable and should be discarded after the end of life. Primary cells have a high density and are slowly discharged. Alkaline batteries and dry cells are examples of primary cells. Li-on Primary batteries most commonly use a reaction between Li and MnO2 to produce electricity
• Secondary Battery: secondary cells are the ones that are rechargeable. Secondary cells have low energy density and are made of molten salts and wet cells. The internal resistance is low and the chemical reaction is reversible. Li-ion secondary batteries use a reaction in which lithium from a lithium/graphite anode is incorporated into Different Li oxides at the cathode

Internal Construction

• The internal workings of a battery are typically housed within a metal or plastic case.
• Inside this case are a cathode, which connects to the positive terminal, and an anode, which connects to the negative terminal.
• These components, more generally known as electrodes, occupy most of the space in a battery and are the place where the chemical reactions occur.
• A separator creates a barrier between the cathode and anode, preventing the electrodes from touching while allowing electrical charge to flow freely between them.
• The medium that allows the electric charge to flow between the cathode and anode is known as the electrolyte.
• Finally, the collector conducts the charge to the outside of the battery and through the load.

LITHIUM-ION BATTERY

• A lithium-ion battery or Li-ion battery is a type of rechargeable battery in which lithium ions move from the negative electrode through an electrolyte to the positive electrode during discharge and back when charging. Li-ion batteries use an intercalated lithium compound as the material at the positive electrode and typically graphite at the negative electrode.

• The anode is usually graphite. However, the repeated insertion of lithium ions into the standard graphite structure in a typical lithium-ion battery eventually breaks apart the graphite. This reduces the battery’s performance and the graphite anode will eventually break down, and the battery will stop working

• In terms of the material used for the cathode, there are quite a few variations—generally made of a combination of lithium, oxygen, and some kind of metal.

TYPES

Six different lithium-ion battery types,

1. Lithium Cobalt Oxide (LiCoO2) — LCO
2. Lithium Manganese Oxide (LiMn₂O₄) — LMO
3. Lithium Nickel Cobalt Aluminium Oxide (LiNiCoAlO2) — NCA
4. Lithium Nickel Manganese Cobalt Oxide (LiNiMnCoO2) — NMC
5. Lithium Iron Phosphate (LiFePO4) — LFP
6. Lithium Titanate (Li2TiO3) — LTO

MATERIALs:

LI-ION BATTERY	ANODE	CATHODE	SEPERATOR	ELECTROLYTE
LCO	Graphite	Lithium Cobalt Oxide	Polyolefin	Ethylene Carbonate
LMO	Graphite	Lithium Manganese Oxide	Polyolefin	Lithium Halide
NCA	Graphite	Lithium Nickel Cobalt Aluminium Oxide	Polyolefin	Ethylene Carbonate
NMC	Graphite	Lithium Nickel Manganese Cobalt Oxide	Polyolefin	Lithium Salt
LFP	Graphite	Lithium Iron Phosphate	Polyolefin	Ethylene Carbonate
LTO	Graphite	Lithium Titanate	Polyolefin	Lithium Salt

CHEMICAL REACTIONs:

LI-ION BATTERY	ANODE REACTION	CATHODE REACTION	OVERALL REACTION
LCO	LiC6→xLi++xe−+C6	xCoO2+xLi++xe−→LiCoO2	C6+xLiCoO2⟷LixC6+xCoO2
LMO	LiC6→xLi++xe−+C6	xMnO2+xLi++xe−→LiMnO2	C6+xLiMnO2⟷LixC6+xMnO2
NCA	LiC6→xLi++xe−+C6	xNiCoAlO2+xLi++xe−→LiNiCoAlO2	C6Li+NiCoAlO2⟷LixCoAlO2+C6
NMC	LiC6→xLi++xe−+C6	xNiMnCoO2+xLi++xe−→LiNiMnCoO2	C6Li+NiMnCoO2⟷LixNiMnCoO2+C6
LFP	LiC6→xLi++xe−+C6	xFePO4+Li++e−→LiFePO4	LiC6+FePO→LiFePO4+C6
LTO	LiTiO3→TiO3 + xLi+ +xe−	xMnO4+xLi++xe−→ LiMnO4	Li4Ti5O12 + xMnO2 → xLiMn2O4 + xTiO2

COMPARISON:

Lithium Cobalt Oxide(LiCoO₂) — LCO

• Its high specific energy makes Li-cobalt the popular choice for mobile phones, laptops and digital cameras. The battery consists of a cobalt oxide cathode and a graphite carbon anode. The cathode has a layered structure and during discharge, lithium ions move from the anode to the cathode. The flow reverses on charge. The drawback of Li-cobalt is a relatively short life span, low thermal stability and limited load capabilities (specific power)

Lithium Cobalt Oxide: LiCoO2 cathode (~60% Co), graphite anode Short form: LCO or Li-cobalt. Since 1991
Voltages	3.60V nominal; typical operating range 3.0–4.2V/cell
Specific energy (capacity)	150–200Wh/kg. Specialty cells provide up to 240Wh/kg.
Charge (C-rate)	0.7–1C, charges to 4.20V (most cells); 3h charge typical. Charge current above 1C shortens battery life.
Discharge (C-rate)	1C; 2.50V cut off. Discharge current above 1C shortens battery life.
Cycle life	500–1000, related to depth of discharge, load, temperature
Thermal runaway	150°C (302°F). Full charge promotes thermal runaway
Applications	Mobile phones, tablets, laptops, cameras
Comments 2019 Update:	Very high specific energy, limited specific power. Cobalt is expensive. Serves as Energy Cell. Market share has stabilized. Early version; no longer relevant.

Lithium Manganese Oxide (LiMn₂O₄) — LMO

• The architecture forms a three-dimensional spinel structure that improves ion flow on the electrode, which results in lower internal resistance and improved current handling. A further advantage of spinel is high thermal stability and enhanced safety, but the cycle and calendar life are limited.
• Li-manganese has a capacity that is roughly one-third lower than Li-cobalt. Design flexibility allows engineers to maximize the battery for either optimal longevity (life span), maximum load current (specific power) or high capacity (specific energy).

Lithium Manganese Oxide: LiMn2O4 cathode. graphite anode Short form: LMO or Li-manganese (spinel structure) Since 1996
Voltages	3.70V (3.80V) nominal; typical operating range 3.0–4.2V/cell
Specific energy (capacity)	100–150Wh/kg
Charge (C-rate)	0.7–1C typical, 3C maximum, charges to 4.20V (most cells)
Discharge (C-rate)	1C; 10C possible with some cells, 30C pulse (5s), 2.50V cut-off
Cycle life	300–700 (related to depth of discharge, temperature)
Thermal runaway	250°C (482°F) typical. High charge promotes thermal runaway
Applications	Power tools, medical devices, electric powertrains
Comments 2019 Update:	High power but less capacity; safer than Li-cobalt; commonly mixed with NMC to improve performance. Less relevant now; limited growth potential.

Lithium Nickel Manganese Cobalt Oxide (LiNiMnCoO2) — NMC

• One of the most successful Li-ion systems is a cathode combination of nickel-manganese-cobalt (NMC). Similar to Li-manganese, these systems can be tailored to serve as Energy Cells or Power Cells.
• There is a move towards NMC-blended Li-ion as the system can be built economically and it achieves a good performance. The three active materials of nickel, manganese and cobalt can easily be blended to suit a wide range of applications for automotive and energy storage systems (EES) that need frequent cycling.

Lithium Nickel Manganese Cobalt Oxide: LiNiMnCoO2. cathode, graphite anode Short form: NMC (NCM, CMN, CNM, MNC, MCN similar with different metal combinations) Since 2008
Voltages	3.60V, 3.70V nominal; typical operating range 3.0–4.2V/cell, or higher
Specific energy (capacity)	150–220Wh/kg
Charge (C-rate)	0.7–1C, charges to 4.20V, some go to 4.30V; 3h charge typical. Charge current above 1C shortens battery life.
Discharge (C-rate)	1C; 2C possible on some cells; 2.50V cut-off
Cycle life	1000–2000 (related to depth of discharge, temperature)
Thermal runaway	210°C (410°F) typical. High charge promotes thermal runaway
Cost	~$420 per kWh[1]
Applications	E-bikes, medical devices, EVs, industrial
Comments 2019 Update:	Provides high capacity and high power. Serves as Hybrid Cell. Favorite chemistry for many uses; market share is increasing. Leading system; dominant cathode chemistry.

Lithium Nickel Cobalt Aluminum Oxide (LiNiCoAlO₂) — NCA

• Lithium nickel cobalt aluminum oxide battery, or NCA, has been around since 1999 for special applications. It shares similarities with NMC by offering high specific energy, reasonably good specific power and a long life span. Less flattering are safety and cost.

Lithium Nickel Cobalt Aluminum Oxide: LiNiCoAlO2 cathode (~9% Co), graphite anode Short form: NCA or Li-aluminum. Since 1999
Voltages	3.60V nominal; typical operating range 3.0–4.2V/cell
Specific energy (capacity)	200-260Wh/kg; 300Wh/kg predictable
Charge (C-rate)	0.7C, charges to 4.20V (most cells), 3h charge typical, fast charge possible with some cells
Discharge (C-rate)	1C typical; 3.00V cut-off; high discharge rate shortens battery life
Cycle life	500 (related to depth of discharge, temperature)
Thermal runaway	150°C (302°F) typical, High charge promotes thermal runaway
Cost	~$350 per kWh[1]
Applications	Medical devices, industrial, electric powertrain (Tesla)
Comments 2019 Update:	Shares similarities with Li-cobalt. Serves as Energy Cell. Mainly used by Panasonic and Tesla; growth potential.

Lithium Iron Phosphate(LiFePO₄) — LFP

• Li-phosphate offers good electrochemical performance with low resistance. This is made possible with nano-scale phosphate cathode material. The key benefits are high current rating and long cycle life, besides good thermal stability, enhanced safety and tolerance if abused.

Lithium Iron Phosphate: LiFePO4 cathode, graphite anode Short form: LFP or Li-phosphate Since 1996
Voltages	3.20, 3.30V nominal; typical operating range 2.5–3.65V/cell
Specific energy (capacity)	90–120Wh/kg
Charge (C-rate)	1C typical, charges to 3.65V; 3h charge time typical
Discharge (C-rate)	1C, 25C on some cells; 40A pulse (2s); 2.50V cut-off (lower that 2V causes damage)
Cycle life	2000 and higher (related to depth of discharge, temperature)
Thermal runaway	270°C (518°F) Very safe battery even if fully charged
Cost	~$580 per kWh[1]
Applications	Portable and stationary needing high load currents and endurance
Comments 2019 Update:	Very flat voltage discharge curve but low capacity. One of safest Li-ions. Used for special markets. Elevated self-discharge. Used primarily for energy storage, moderate growth.

Lithium Titanate (Li2TiO3) — LTO

• LTO (commonly Li4Ti₅O₁₂) has advantages over the conventional cobalt-blended Li-ion with graphite anode by attaining zero-strain property, no SEI film formation and no lithium plating when fast charging and charging at low temperature. Thermal stability under high temperature is also better than other Li-ion systems; however, the battery is expensive

Lithium Titanate: Cathode can be lithium manganese oxide or NMC; Li2TiO3 (titanate) anode Short form: LTO or Li-titanate Commercially available since about 2008.
Voltages	2.40V nominal; typical operating range 1.8–2.85V/cell
Specific energy (capacity)	50–80Wh/kg
Charge (C-rate)	1C typical; 5C maximum, charges to 2.85V
Discharge (C-rate)	10C possible, 30C 5s pulse; 1.80V cut-off on LCO/LTO
Cycle life	3,000–7,000
Thermal runaway	One of safest Li-ion batteries
Cost	~$1,005 per kWh[1]
Applications	UPS, electric powertrain (Mitsubishi i-MiEV, Honda Fit EV), solar-powered street lighting
Comments 2019 Update:	Long life, fast charge, wide temperature range but low specific energy and expensive. Among safest Li-ion batteries. Ability to ultra-fast charge; high cost limits to special application.

Typical specific energy of lead-, nickel- and lithium-based batteries.

• NCA enjoys the highest specific energy; however, manganese and phosphate are superior in terms of specific power and thermal stability. Li-titanate has the best life span

CONCLUSION

• Li-aluminum (NCA) is the clear winner by storing more capacity than other systems, this only applies to specific energy. In terms of specific power and thermal stability, Li-manganese (LMO) and Li-phosphate (LFP) are superior. Li-titanate (LTO) may have low capacity but this chemistry outlives most other batteries in terms of life span and also has the best cold temperature performance. Moving towards the electric powertrain, safety and cycle life will gain dominance over capacity.