Has there ever been a 10.0 or greater earthquake in history?

Not that has ever been recorded by man. The largest recorded earthquake occurred off the west coast of Chile in 1960 and had a magnitude of 9.5.

It is thought that the impact that occurred 65.5 million years ago creating the Chixulub crater beneath the Yucatán Peninsula in Mexico (and thought to have contributed to the extinction of the dinosaurs) yielded energy equivalent to an earthquake of magnitude 12.5.