The only problem is that any seed generated by Electrum is not BIP44 compatible. You will have to open Electrum, select Wallet -> Private keys -> Export. Then you can sweep those private keys into Coinomi wallet. Note that a transaction will be broadcasted for each Bitcoin address. Once your transactions get confirmed, you will be able to spend your coins directly from Coinomi.

I haven't used Electrum for some time (version 3.3.4) but I decided to launch it today in order to help the guy from this thread. It managed to synchronise once after relaunching Electrum a few times. Now, my wallet does not synchronise either. Don't do anything unless Electrum developers address this issue. Your coins are safe so don't worry about it. You can import your seed to some other wallet software if you have to spend your coins urgently.