For the life of me I can't remember this series of books. Humanity sends an expedition to negotiate with an alien race, and they discover that humanity's been building a fleet in secret so they turn off all electricity on Earth, and ultimately destroy the moon to deny humans access to space.
This is "Earthbound" by Joe Halderman.
The blurb mentions a group of aliens (the "others") feeling threatened by Earth's fleet:
The mysterious alien Others have prohibited humans from space travel-destroying Earth's fleet of starships in a display of unimaginable power. Now Carmen Dula, the first human to encounter Martians and then the mysterious Others, and her colleagues struggle to find a way, using nineteenthcentury technology, to reclaim the future that has been stolen from them.
and the review below mentions the destruction of the moon and the disablement of electronic devices:
The story begins a few days after the group that was out to visit The Others, returns to an Earth on which 50 years have passed, and The Others have smashed the moon and disabled all electromechanical devices. Seriously, this book should have started with a synopsis of the earlier two books.