What Lithium cell chemistry to choose?

[Wilson__]

Which lithium cell chemistry for mobile and wearable devices is good for high energy, small size and weight, at 50 to 100mAh:

Occasionally short pulse (2 seconds or less) discharge at 1C.

Routine discharge 15mA for ms, once per hundreds of seconds

Weeks to a few months per recharge.

No need for fast recharge time.

Price point is medium to high consumer electronics (seem price is not high for this small mAh).

Searching shows that there are four major types:

Lithium Cobalt Oxide(LiCoO2) — LCO

Lithium ion manganese oxide battery (LMO)

Lithium nickel manganese cobalt oxides (abbreviated NMC, Li-NMC, LNMC, or NCM

Lithium iron phosphate battery (LiFePO 4 battery) or LFP battery (lithium ferrophosphate)

Many thanks

[thm_w]

Have you calculated what space you have available and what energy density that works out to?
Desired cycle life?

LFP and LTO will be most reliable and safest, but will be most expensive and least energy dense. And could be harder to deal with due to the non-common voltage range.

You can look up some commonly available parts and make comparisons:
- Samsung galaxy watch 4 = 350mAh
- Apple watch series 3 = 340mAh A1875
- Fitbit luxe = 50mAh LSS271120P

[amyk]

Something like an LIR2050? Your application is not particularly demanding, and NMC is probably the most common and cheapest these days.

[Wilson__]

Many thanks.  From web info, seem leading energy density per kg or volume are:

LCO is 200Wh/kg.    LMO 150

LCO is 400Wh/litre,  LMO 350

Need to be compatiable with standard charging controller IC.