I have both a Standard Horizon (7yo) and a Uniden (4yo) hand held radios. They both are Lithium Ion rechargeable but each also came with an additional battery pack that accepts AA batteries. I use the rechargeable primarily but always carry the battery pack as backup. Both of my radios have an amazing rechargeable battery life on standby or scanning mode .
If the battery pack does not come with the radio you might be able to purchase it separately from the manufacturer.