The Stem of TIme by Janeau L'voe

Stem of Time

Jillian is a scientist, determined to cure cancer, and she has the brains to do it too, she just doesn't have the time. In order to make more time, she invents a time stem, enabling her to slow time for herself and allow her to do the work of five people.

But, she never expected the consequences this could have: she draws the unwanted attention of the Council, has an assassin sent after her, a bounty placed on her head and gains a new husband, whom she's never met. And all she wanted to do was to cure cancer.