Please explain pros/cons of IMR versus standard Li-Ion rechargeables

Nobody uses pure IMR anymore, everybody uses some hybrid chemistry in 2020.

For 18350 get either Vapcell or Shockli in unprotected format, or Keeppower or Orbtronic in protected format. You will get 1000-1100mAh from any of these brands. Large companies like Panasonic don’t bother making 18350s.

I almost feel guilty for starting this conversation as you guys have been so incredibly helpful! It all started with this statement from the “Modlite” website:

Battery Chemistry
Here is what separates IMR cells from standard Li-Ion cells. IMR cells used in our 18350 batteries are a specialized Li-Mn (Lithium Manganese) chemistry specifically designed for high-drain applications. While they excel at delivering massive discharge rates, their capacity is much more limited than a Li-Ion of the same size.

Since my need is for a small radio, I was assuming that I did NOT need “massive discharge rates”. Rather, that “capacity” would be more important for this application and as such the “lithium ion of the same size” they mentioned would be preferable. Yes/No?

You’re absolutely right! I can’t even remember the acronyms of the new chemistries now but most of them are safer and perform almost as well or even better than IMR. INR is one for sure I know, but I believe most cells use hybrid chemistries that attempt to have the best of all worlds while being as safe as possible. Nowadays you can pretty much go with any cell you want unless you know you need high current drain, which for most people will be limited to true hotrod flashlights and crazy “cloud chasing” ecigs.

As long as you get protected if you need it and choose button/flat top to ensure good contact just get the highest capacity you can - since most are usually about the same price.

The discussion for 18350 is moot at the moment because the highest capacity cell (labelled between 1100 and 1300mAh depending on brand) has a high discharge rating as well, maybe even the highest rating. I think the 4 brands use the same cell, I believe the small differences in test results come from batch variability.

Go to List of tested batteries and filter by 18350 size. You can also use the graphic comparator linked in that page but the difference is very small.

Yep, that’s probably due to newer tech/developments that 18650/21700 have had finally being applied to the 18350 format I would assume?