I would stay far away from lithium rechargeable batteries if I were you. The 1.5v AA style or others have a regulator of sorts (buck convertor?) that drops the (3.7v?) down to 1.5v. If that convertor goes
buckus your electronics (scanner) are toast. It's why I don't use rechargeable lithium's anymore and just buy rechargeable NiMH Energizers. Certainly not as Amp hour great as the lithiums, but at least they won't have the risk of over volting and frying my expensive scanners. Note: this applies to the rechargeable lithium, not the single use versions like you find at a grocery store that cost two lungs, a pancreas and stock options. Those are pretty decent. And energizer is in the Guinness Book of World Records for the longest lasting version, too.
Energizer® sets record for longest-lasting AA battery just in time for the holidays Though, I'd like to see the numbers. Could be by 2 minutes for all we know. LOL Also note: The rechargeable NiMH batteries may have a Non-UL listed charger. If so, don't leave the room while charging... That goes for CCRs (Cheap Chinese Radios) for all that matter.
As was mentioned, you can buy a portable lithium battery bank that has USB and use that with a long cable. Make sure the USB cable is the same connector as the one for the 325P. I believe it's USB mini B.
USB-C, USB-B, and USB-A: What's the Difference? - ViewSonic Library
I have this one. Bought it from Newegg.:
Tripp Lite Portable 2-Port USB Battery Charger Mobile Power Bank 10.4k mAh power bank - Li-Ion - USB - UPB-10K4-S2U - Office Basics - CDW.com
Also have an Adata portable battery bank bought from NewEgg.
Both are many years old but still have a charge. I rarely have to recharge them just sitting here which I find odd compared to my drone batteries and other lithium batteries. Probably because DJI supplies cheap batteries or something.
So there you have it. If others have good luck with rechargeable lithium AA batteries all the more power (no pun intended). But that convertor there I don't trust with my $400+ scanners.