Superman is the poster boy for overpowered characters in comics, with a veritable multitude of powers, astonishing displays of sheer strength (like bench-pressing the entire planet without breaking a sweat), and even ways to regenerate himself were he ever to be beaten, like resurrecting more than once. He's meant to look as untouchable and undefeatable as what he fights for: truth, justice and virtue.
This is all great - he's a powerful symbol of hope that makes us feel like these ideas are unbreakable and inspires us to follow in his footsteps - but it also makes the defeats by his foes feel like a heavy blow. What better way to illustrate the threat that a villain poses to humanity and all existence than defeating the guardian of all that's good?
Because of this, writers often make a point to never let our big hero be overshadowed by his colleagues when working with them in the Justice League. However, with a publication history being 18 years shy of a century (WOW) and his popularity still going strong, we've seen him at his lowest and highest, so there's no way any newer hero could be more powerful than he is, much less hanging out with him in the JL, right?
Well... let's just say that 10 doesn't cover them all.
Starting off strong, hear me out.
Sure, he can't punch foes into the atmosphere or melt a glacier just by looking at it, but Batman's power comes not from brawn, but brain. The amount of feats accomplished by the Dark Knight is astronomical, specially for a man with no powers, justifying his place amongst earth's guardians.
Whether he's dismantling crime syndicates and solving gruesome murders in Gotham or contending with an invading alien force, Batman will always find a weakness and exploit it using - or sometimes even creating - the right tool for the job. (With enough prep-time, of course.)
The extent of his talents and will to do whatever is necessary is evidenced by the existence of the Babel Protocol, a way to neutralize every single one his fellow members of the Justice League should they step out of line.
As far as Superman goes, Batman is able to exploit his most prominent and well known weaknesses, Kryptonite and red sun radiation, fashioning them into a variety of tools to render the Man of Steel into nothing but a mortal man, then beating him with his superior fighting skills and wits. We even see this happen in a multitude of occasions, whether it be canonically or in alternate universes such as The Dark Knight Returns.
But, let's face it, Batman's real power comes from his popularity and plot armor. I'd like to see Superman be blasted by Darkseid's fully powered omega beams and be sent to the beginning of human history instead of just dying.