What's all this about the different chemistries?


Staff member
Jan 7, 2017
11. What's all this about the different chemistries?

This whole topic has a backpack full of naming issues, not only because people use it wrong or simplify it, but also because the manufacturers don't always state the complete chemistry and because there are "in between / hybrid chemistries" which are a mix. Also some terms overlap with other ones.

The absolute baseline is the term lithium cell.This is always correct, but not always very precise. Depends on whether this kind of precision is important. It's like saying all cars, trucks, etc are vehicles.

LiIon is often usedfor all lithium chemistries with a fluid electrolyte and 3.6/3.7V nominal voltage, that covers basically all cylindrical cells. If you want to bemore precise then you have todifferentiate between their chemistries. Most common ones are lithium cobalt / LiCo / ICR cells, usually found in laptops, powerbanks and so on. Then there is lithium manganese / LiMn / IMR which, unlike the ICR cells, are high drain cells for powertools and similar applications. They were superseded, sort of, by (and now fasten your seatbelts) lithium nickel manganese cobalt / LiNiMnCo / INR cells. This is a hybrid chemistry, not hard to figure out why. These are the main three chemistries. Obviously some manufacturers also vary the amounts of the respective element in the mix. Samsungs ICR cells aren't chemically identical to the LG ones and also almost every manufacturer makes several different cells of each type.

There are more chemistries beside these three, a notable one is Teslas lithium aluminium chemistry which is like INR but swaps manganese for aluminium. It is called NCA.
Lithium iron phosphate / LiFe / LiFePo / IFR cells belong to the aforementioned ones technically, but are often handled separately because of their lower nominal voltage of 3.2V.
All of them come in cylindrical forms, LiFe is also often in prismatic forms. The other LiIon chemistries come in prismatic forms as well, but not as often as LiFe.

Lithium polymer cells always come in pouch form. They use similar chemistries with cobalt, manganese and so on, but their electrolyte isn't fluid. It isn't completely solid either but a semi solid gel. Basically it is a kind of plastic. They have the advantage of being lightweight and can easily be built in any shape you need. These are usually in devices like cell phones, tablets, small rechargeable devices like dog collars, small toys, etc.

LiIon: Refers to all of them, specifically ICR, IMR and INR, nominal voltage 3.6V-3-7V, usually cylindrical cells, sometimes prismatic
ICR: LiIon, made to provide highest capacity for applications where runtime is important but high current discharge isn't
IMR: LiIon, high drain cells for applications with high discharge currents
INR: LiIon, like IMR with some of the benefits of ICR while not losing IMR qualities completely

LiFe/LiFePo/LiFePo4/IFR: LiIon, but often mentioned separately because of lower nominal voltage of 3.2V, cylindrical and prismatic cells

LiPo: Like the other LiIons, but separated from them by their semi solid electrolyte, always in non-standard pouch cells

DISCLAIMER: I am by no means an expert on any one or all of these fields/questions/topics. The results of this FAQ is a collaboration of multiple different members to come up with a common list of questions that would be asked and we have tried to answer. I was the member who was chosen to post the FAQ. If you have question that goes beyond the FAQ, please post your questions in the relevant section pertaining to your inquiry. Thank you and have a nice day