Created in 1939 by artist C. C. Beck and writer Bill Parker, the New 52 version of Billy Batson's alter-ego will run as back-up tale in Justice League by writer Geoff Johns and artist Gary Frank. According to Johns, the character will "be far more rooted in fantasy and magic than it ever was before." Hence the cloak.
“With SHAZAM! Gary and I will be focusing on the magic hero instead of the super hero,” Johns told DC's The Source blog. “For centuries, science has ruled the world, but now magic is returning. We’re telling the story of the hero’s young alter ego, Billy Batson, a foster kid at a crossroads in his life. The question is, how does the emotional journey of this troubled teenager collide with the fate of the world? The Rock of Eternity and the legacy of SHAZAM! will be explored in a different way as the extent of Billy’s connection to the magic world around him is greater than ever before. The story will have a profound impact on Justice League later in the year and you’ll see new characters, locations and creatures along with the classics from the SHAZAM! universe. Billy’s friends and enemies will be along for the ride.”