In January 2011, the group began work on their second studio album with previous songwriter and producer Steve Mac. In February 2011, it was revealed the group would be releasing the official Comic Relief single for 2011. In April 2011, the group embarked on their first headline tour, playing 16 dates in 12 different UK cities. The tour was in support of their debut album The Wanted but whilst on tour, the group previewed the song, "Lightning" from their new album. The track was co-written by the band and Ed Drewett. Max George confirmed on 28 September that the album was complete and the following day, Nathan Sykes confirmed the album would be released with the title Battleground.
In March 2012, Billboard reported that Battleground was "slated to arrive stateside this fall" as the band's second US release, after their debut EP. This did not happen, however, and instead their first album to be released in the US will be their third overall album, Word of Mouth.
"Gold Forever" was released as the lead single from the album on 13 March 2011. It was also the official Comic Relief single for 2011. The track debuted at number three in the UK, number two in Scotland and number 13 in Ireland. It is currently their third most successful single, spending a total of eight weeks on the UK Top 75. It was also released as the third single from the group's debut US album, The Wanted: The EP.
"Glad You Came" was released on 10 July 2011 as the second single. It became their second UK number one and first number one in Ireland, where it spent five weeks at the summit. The track is also their first to be successful on an international basis, charting at #20 in both Australia and New Zealand, number 12 in the Netherlands and also reached number one on the Canadian Hot 100. The song is also a commercial success in the United States, peaking at number three on the Billboard Hot 100 chart as of 29 March 2012. It is currently their most successful single in the UK. It was also released as the second single from The Wanted: The EP.
"Lightning" was released on 16 October 2011 as the third single. It reached number two in the UK and Scotland and number five in Ireland. In Australia, the track has peaked at number 79. The track is currently their third most successful single. "Warzone" was confirmed as the album's fourth single in early November. It was released on 26 December 2011.
The album received mostly favourable reviews from music critics. Jon O'Brien wrote for AllMusic that "Battleground, is disappointingly a little more pedestrian than its predecessor", writing that "Battleground should still consolidate their position as heirs to the boy band throne, but with the likes of One Direction now snapping at their heels, they'll have to rediscover their inventive streak in the future if they are to ever take the crown." Nick Levine wrote for BBC that the album is "a solid pop platter that's not lacking in personality – even if the latter does manifest itself in a smattering of lyrics clunkier than testing day at the seat belt factory." Robert Copsey wrote for Digital Spy that "Though the end result shows that they may have taken the battle of the boybands a touch too seriously, much to their credit they come out the other side largely unscathed." David Griffiths wrote for 4Music that "it's an album which wisely leaves the listener wanting more and suggests that this is a band with a very bright future." Matthew Horton wrote a mixed review for Virgin Media that "It's a curiously bloodless affair though, with none of the boys yet to establish an identity, and too much sails past without leaving an impression."
The album debuted at number four in Ireland, becoming their first top ten album in the country. In the United Kingdom, the album debuted at number five. It sold 47,530 copies in its first week. Although debuting at one position lower than their debut album, its sales were 22.91% copies higher. It has since been certified gold by the British Phonographic Industry (BPI) for shipments of 100,000 copies in the UK.