Week 1 Understanding Different Battery Chemistry

1. 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.Give your detailed explanation on it

Answer:

The table includes materials & chemical reactions occurring at the anode and cathode of LCO, LMO, NCA, NMC, LFP, and LTO types of lithium-ion cells as shown below.

A lithium-ion battery is a secondary type of battery which are commonly used in portable electronics & electric vehicles. Similar to a conventional battery, a Lithium-ion battery includes cathode(+ve electrode), anode(-ve electrode), & electrode as conductor. The cathode is a metal oxide material & anode consists of porous carbon. During the discharging process, the ions flow from the anode to the cathode through the separator & electrons flow from the cathode to the anode. similarly, the opposite happens during the charging process.

Types of Li-ion batteries:

1. Lithium cobalt oxide(LCO) - LiCoO₂

The Li-cobalt batteries are used in mobile phones, laptops, and digital cameras due to their high specific energy popularity. The cathode has a layered design and during charge, the ions flow from the cathode to the anode through the separator & electrons flow from the anode to the cathode. The downside of Li-cobalt is its relatively short life span, low thermal stability, and limited load capabilities (specific power) & safety.

2. Lithium manganese oxide(LMO) - LiMn₂O₄

In 1983, the Li-ion with manganese spinel was first published in the Materials Research Bulletin. In 1996, Moli Energy commercialized a Li-ion cell with lithium manganese oxide as cathode material. The design forms a three-dimensional spinel structure that improves ion flow on the anode & cathode, which results in lower internal resistance and improved current handling. A further benefit of spinel is high thermal stability and upgraded safety, but the cycle and life span are limited.

3. Lithium nickel cobalt aluminium oxide(NCA) - LiNiCoAlO₂

Lithium nickel cobalt aluminum oxide battery, or NCA, has been around since 1999 for extraordinary applications. It shares similitudes with NMC by offering high specific energy, reasonably good specific power, and a long life span. The drawbacks are less safety and cost. NCA is a further development of lithium nickel oxide; adding aluminum gives the chemistry greater stability.

4. Lithium nickel manganese cobalt oxide(NMC) - LiNiMnCoO₂

Quite possibly the best Li-ion system is a cathode combination of nickel-manganese-cobalt (NMC). Like Li-manganese, these systems can be custom-made to serve as Energy Cells or Power Cells. For example, NMC in a 18650 cell for moderate load conditions has a capacity of about 2,800mAh and can deliver 4A to 5A; NMC in the same cell optimized for specific power has a capacity of only about 2,000mAh but delivers a continuous discharge current of 20A. A silicon-based anode will go to 4,000mAh and higher but at reduced loading capability and limited cycle life. Silicon added to graphite has the disadvantage that the anode grows and shrinks with charge and discharge, making the cell mechanically unstable.

Battery makers move away from cobalt systems toward nickel cathodes due to the high cost of cobalt. Nickel-based systems have a higher energy density, lower cost, and longer cycle life than the cobalt-based cells but they have a slightly lower voltage.

5. Lithium iron phosphate(LFP) - LiFePO₄

The University of Texas & others discovered phosphate as a cathode material for rechargeable lithium batteries in 1996. Li-phosphate offers great electrochemical performance with low resistance. This is made possible with nano-scale phosphate cathode material. The key benefits are high current rating and long life span, other than good thermal stability, enhanced safety, and tolerance if abused. Li-phosphate is more tolerant to full charge conditions and is less stressed than other lithium-ion systems whenever kept at high voltage for a prolonged time.

6. Lithium Titanite(LTO) -

Batteries with lithium titanate anodes have been known since the 1980s. Li-titanate replaces the graphite in the anode of a typical lithium-ion battery and the material structures a spinel structure. The cathode can be lithium manganese oxide or NMC. Li-titanate has a nominal cell voltage of 2.40V, can be fast charged, and delivers a high discharge current of 10C, or 10 times the rated capacity. The cycle count is supposed to be higher than that of a regular Li-ion. Li-titanate is safe, has excellent low-temperature discharge characteristics, and obtains a capacity of 80 percent at –30°C (–22°F). These are very expensive.

2. Compare the differences between each type of Li+ion batteries based on their characteristics

Answer:

1. Based on a scale of 0 to 4:

Other than the above characters some of the characters are differentiated below.