Those a Bech32 segwit addresses defined in BIP 173 by Peter Wuille
https://github.com/bitcoin/bips/blob/master/bip-0173.mediawikiWith bc1 addresses your transactions are 38% smaller than that of legacy transactions of the same input/output.
Eg for 1 input and 2 outputs, a legacy (address starts with 1) transaction is 226 bytes, but a Bech32 transaction is just 141vbytes.
Right now only Electrum supports the creation of wallets with this address type (select "native segwit" when you're setting up)
Also, it's not backwards compatible, meaning wallets without segwit support won't be able to send funds to this type of address.