would an electromagnet with a 3.7 volt lithium ion battery have an effect on devices and/or satelite signals like cell phones

Some effect is there buts its almost negligible, and much less as compared to Ni-Cad batteries. Also this battery if recyclable, less toxic as well as remain in use for a very long time. Its used in satellites as well, and in one of them, it is now running without any fault for almost 13 years.

Explanation:

And you should check the list of noble price. Three great scientists John B. Goodenough, Akira Yoshino and Stanley Whittingham have got the noble prize for their work on Lithium Ion Batteries this year.