Lithium iron phosphate batteries have advantages like being safer and more environmentally friendly. Have you considered using 18650 cells with LFP chemistry in the Open Air Max? You have decided on Samsung INR1860-35E as you have mentioned in AirGradient Forum – Introducing the Open Air Max! (timecode 15m52s)
I understand that they are far less common than NMC/NCA which is the chemistry of basically all 18650 cells.
Noteworthy products that use LFP 18650 cells: MNT Reform
I am very interested in a mobile version, either with an internal battery, or a device that is optimized to work with an external battery back like the common small USB batteries to charge phones or whatever.
This is what the Open Air Max has in mind, with a solar panel and batteries.
The First Professional-Grade, Affordable Air Quality Monitor
The original poster of this thread was asking about different battery types for this model, but AirGradient has developed and tested around the types of cells they are shipping with