The singer told Metro that the group had written 12 out of the 16 tracks on the deluxe version of the follow-up to last year's self-titled debut.
"It's a slightly older sound," said George. "The first was generic pop, this is a bit darker with a bit of dubstep on some songs. It's more personal - it's more our work than anyone else's."
Asked if the group were now serious musical artists, rather than a boyband, he added: "We always have been really.
"We're not a dancing boyband, we're not over-choreographed or into how we look - we just like good music."
"We wrote a little bit on the first album but this time we owned it," George's bandmate Jay McGuiness said earlier this year.
"We didn't just sit in the room and watch it happen. We crafted this one. It's really exciting."
Fellow Wanted star Siva Kaneswaran recently told Digital Spy that Battleground has an "international" feel.
> The Wanted tease fight scene in new music video for 'Warzone'
> The Wanted's Max George reviews this week's singles
Watch The Wanted 'Lightning' music video below: