"You're a good man, Captain. With or without powers" - Batman
This picture is based on a story from the old DC ( 1986/7 - 2011 ) Captain Atom #33 ( 1989 ) where Batman stops the 'training' bout between the two heroes.
Having his link to the quantum field blocked, Nathaniel Adam refused to allow his power loss to prevent him continuing as Captain Atom and leader of the Justice League Europe. Heading to Gotham city he seeks out Batman for a sink or swim course in non powered superheroics. Initially unimpressed now that Nathaniel lacked his Superman class powerlevels, however after a short bout Batman regards the Captain as being capable enough in combat to be of some use and they track down and defeat the Scarecrow. Batman had a degree of respect for the Captain after this.
It was a nice reminder that even without his powers Captain Atom could still fight pretty well. Still, while he refused to show it, his spar with the dark knight had made it clear to him that for all his military hand to hand training and experience, Batman was his superior and hit like a truck.
Captain Atoms mesh costume was a homage to the Charlton Comics version of the character, who wore a Yellow and red boiler suit with a mask. It was kind of fun to draw classic DC era Batman with the yellow chest symbol that he wore at the time.