I bought a Droid Bionic several years ago. Enough years ago that as of today, I own it; so maybe four years. Anyway, as of late, the battery has not been holding a charge well. It's never had good battery life, but lately it was ridiculous. The first replacement battery came from Amazon. It was a dud, it could not supply enough power to get the phone through the power up sequence after being plugged in all night.
The second battery seems to work. Here is the significant thing. The battery on the left is the old one. It's curved on both sides. See how the corners don't make contact with the dinette surface? The new battery is on the right, and is much flatter.
So, if you own an older phone, with a removable battery, take it out and look at it once in awhile. I didn't know phone batteries would swell up and eventually leak. Now we know, so don't let this happen to you!