Hi @alexsh1 , yes I recently find out those 1.5V rechargable lithium batteries. I haven't bought one myself but I'm wondering if they have an internal step-down circuit there from 3.7V there
Most of the rechargeable batteries will have a self-discharge much greater than non-rechargable Alkaline/Lithiun. The rechargeable lithium-ion have not so much... maybe 2%/month, but still adds up if you wish to run your project for 1 or 2 years.
Anyway, my point here is if you just want something to stay running for over one year in your basement for example, any rechargeable battery can add a significant cost and some trouble as you'll need to use a very specific rechargeable cell. It's not very practical IMO. On the other hand cheap non-rechargeable Alkaline and Lithium are common, offering very low self-discharge and are more resilient to temperature variations.
In the other hand if you project is a toy or a hand held device which need new batteries every second week, well, rechargeable lithium seems to be the way to go. In this case maybe just stick a LiPo or a big 18650 battery... just need to pay attention for any possible regulation as those ones the voltage will vary from 4.2V (fully charged) to 3V (discharged)... and 4.2V might fry some 3.3V component
At the end it all comes down to the project design and how it's supposed to run. If you have access to energy harvesting, like a sensor in your roof, even more fun to design...