Week 1 Understanding Different Battery Chemistry
Week 1 Challenge:
Li-ion Batteries
One kind of rechargeable battery is a lithium-ion battery, also known as a Li-ion battery. Applications for lithium-ion batteries in the military and aerospace are becoming more and more widespread. They are frequently utilised in portable gadgets and electric vehicles.
Lithium-ion uses a cathode (positive electrode), anode (negative electrode), and electrolyte as conductor, just like lead- and nickel-based architecture. A metal oxide serves as the cathode, and porous carbon serves as the anode. Ions move through the electrolyte and separator from the anode to the cathode during discharge; during charge, the ions move in the opposite direction from cathode to anode. Figure 1 shows how the procedure works.
Types of Li-ion Cells
Lithium Cobalt Oxide(LiCoO2) — LCO
Li-cobalt is a common choice for cell phones, laptops, and digital cameras due to its high specific energy. A cobalt oxide cathode and a graphite carbon anode make up the battery. Lithium ions flow from the anode to the cathode during discharge due to the cathode's layered nature. On charging, the flow changes. Li-cobalt has a constrained range of load capabilities, a short life duration, and poor thermal stability (specific power).
Lithium Manganese Oxide (LiMn2O4) — LMO
The Materials Research Bulletin initially reported on Li-ion with manganese spinel in 1983. Lithium manganese oxide used as the cathode material for the Li-ion cell that Moli Energy launched in 1996. The construction creates a three-dimensional spinel structure on the electrode to enhance ion flow, which lowers internal resistance and enhances current handling. High thermal stability and improved safety are further benefits of spinel, although its cycle and calendar lives are constrained.
Lithium Nickel Cobalt Aluminum Oxide (LiNiCoAlO2) — NCA
Since 1999, lithium nickel cobalt aluminium oxide batteries, or NCAs, have been used for specialised purposes. It has high specific energy, decent specific power, and a long life duration, which are parallels to NMC. Cost and safety are less appealing. Lithium nickel oxide has been developed further into NCA, which adds aluminium to make the chemical more stable.
Lithium Nickel Manganese Cobalt Oxide (LiNiMnCoO2) — NMC
An effective Li-ion system uses nickel, manganese, and cobalt as the cathode (NMC). These systems can be customised to function as Energy Cells or Power Cells, similar to Li-manganese. For instance, NMC in an 18650 cell optimised for specific power has a capacity of just around 2,000mAh but offers a continuous discharge current of 20A. NMC in the same cell designed for moderate load situation has a capacity of about 2,800mAh and may deliver 4A to 5A.
Lithium Iron Phosphate(LiFePO4) — LFP
Li-phosphate has a low resistance and strong electrochemical performance. Phosphate cathode material on a nanoscale enables this. The main advantages include a high current rating, a long cycle life, strong thermal stability, increased safety, and abuse tolerance. If sustained at high voltage for an extended period of time, lithium-phosphate is more resilient to full charge circumstances and experiences less stress than other lithium-ion systems. In exchange, its lower nominal voltage of 3.2V/cell lowers the specific energy below that of lithium-ion with a cobalt blend.
Lithium Titanate (Li2TiO3) — LTO
Since the 1980s, lithium titanate anodes have been used in batteries. In the anode of a conventional lithium-ion battery, lithium titanate takes the role of graphite and crystallises into a spinel structure. Lithium manganese oxide or NMC can be used as the cathode. Li-titanate batteries deliver a high discharge current of 10C, or 10 times the rated capacity, and have a nominal cell voltage of 2.40V. They can also be quickly charged. It is claimed that the cycle count is higher than that of a typical Li-ion. At -30°C, lithium titanate has an 80 percent capacity and outstanding low-temperature discharge characteristics.