Outdoor Solar Lights

I have some cheap solar powered lights. They each have 1 ni-cad??? battery.
Can I use higher rated batteries as long as they are AA size?
Also if I use higher rated batteries ex 1200 instead of 600….will this help my lights to be brighter for longer? thanks for the help in advance.
thanks aussie

I had one of those lights quit working and I had to break it to get inside and fix the broken wire. It is now my toy that lays on my desk. It has 2 ni batteries in it rated at 600. I replaced them with 2 rated at 2500. They charge great and work great. But the light don’t seem any brighter. I did find out with the one I have that when the switch is turned off the batteries will not charge either.