We often talk about ternary lithium batteries or iron-lithium batteries, which are named after the positive active material. The six common types of lithium batteries include: lithium cobalt oxide, lithium manganate, lithium nickel cobalt manganate (NCM), lithium nickel cobalt aluminate (NCA), lithium iron phosphate, and lithium titanate.

1. Lithium cobalt oxide (LiCoO2)

Its high specific energy makes lithium cobalt oxide a popular choice for cell phones, laptops and digital cameras. The disadvantages of lithium cobalt oxide are relatively short lifetime, low thermal stability and limited load capacity (specific power). Like other cobalt hybrid lithium-ion batteries, lithium cobalt oxide uses a graphite anode, and its cycle life is mainly limited by the solid electrolyte interface (SEI), which is mainly manifested in the gradual thickening of the SEI film and the negative electrode plating during fast charging or low temperature charging. Lithium problem. Newer material systems add nickel, manganese and/or aluminum to improve life, load capacity and reduce cost.

Lithium cobalt oxide excels in high specific energy, but only provides mediocre performance in terms of power characteristics, safety and cycle life.

2. Lithium manganate (LiMn2O4)

Spinel lithium manganate batteries were first published in Materials Research in 1983. In 1996, Moli Energy commercialized lithium-ion batteries with lithium manganate as the cathode material. The architecture forms a three-dimensional spinel structure that improves ion flow across the electrodes, thereby reducing internal resistance and improving current-carrying capacity. Another advantage of spinel is high thermal stability and improved safety, but limited cycle and calendar life.

Low battery internal resistance enables fast charging and high current discharge. Type 18650 cells, lithium manganate batteries can be discharged at a current of 20-30A with moderate heat accumulation, and the battery temperature cannot exceed 80°C. Lithium manganate is used in power tools, medical devices, and hybrid and pure electric vehicles. The capacity of lithium manganate is about one-third lower than that of lithium cobaltate. Design flexibility enables engineers to choose to maximize battery life, or to increase maximum load current or capacity.

Pure lithium manganate batteries are no longer common today; they are only used in special cases.

Most lithium manganate is mixed with lithium nickel manganese cobalt oxide (NMC) to increase specific energy and prolong life. This combination brings out the best performance from each system, and most EVs like the Nissan Leaf, Chevrolet Volt and BMW i3 opt for LMO (NMC). The LMO part of the battery can reach around 30% and can provide higher current during acceleration; the NMC part provides a long range.

Li-ion battery research tends to combine lithium manganate with cobalt, nickel, manganese, and/or aluminum as active cathode materials. In some architectures, a small amount of silicon is added to the negative electrode. This provides a 25% capacity boost; however, silicon expands and contracts with charge and discharge, causing mechanical stress, and the capacity boost is often tightly linked to short cycle life.

3. Lithium nickel cobalt manganate (NMC)

One of the most successful Li-ion systems is the cathode combination of nickel manganese cobalt (NMC). Similar to lithium manganate, this system can be tailored for use as an energy or power battery. For example, an NMC in an 18650 battery under moderate load conditions has a capacity of about 2,800mAh and can provide 4A to 5A discharge current; the same type of NMC, when optimized for a specific power, has a capacity of only 2,000mAh, but can provide 20A of Continuous discharge current. The silicon-based negative electrode will reach more than 4000mAh, but the load capacity is reduced and the cycle life is shortened. Silicon added to graphite has the defect that the negative electrode expands and contracts with charging and discharging, making the battery mechanically stressed and structurally unstable.

The secret of NMC is the combination of nickel and manganese. Similar to this is table salt, where the main components sodium and chloride are toxic on their own, but they are mixed together as seasoning salt and food preservatives. Nickel is known for its high specific energy but poor stability; the manganese spinel structure can achieve low internal resistance but low specific energy. The advantages of the two active metals are complementary.

NMC is the battery of choice for power tools, e-bikes and other electric powertrains. The positive electrode combination is usually one-third nickel, one-third manganese and one-third cobalt, also known as 1-1-1. This provides a unique blend that also reduces raw material costs due to reduced cobalt content. Another successful combination is NCM, which contains 5 parts nickel, 3 parts cobalt.