PSP Go Battery Modding

Hello. I just ordered a PSP Go. It's in the mail and I am quite excited about. I do hear however that the battery life is mediocre. That's fine, I'll live. But I was looking through some teardowns of the unit and it looks like the battery could easily be replaced with one of higher capacity from like a phone or other portable device. Do any of you know of a similar specced battery with a higher capacity that I could replace it with? Or just have any general info about modding the go to have greater battery capacity?