From a practical standpoint, 2450kv 2212 on 1045 is too much prop. If you want more power, either current or voltage must increase, since you're not changing voltage, current will increase significantly.
Increasing the cell count gives you the same change in RPM, but with more granularity. I assume you're using 3S right now, 4S might do it, but keep an eye on temperatures. 1045 is commonly a "slowflyer" style propeller, with a thin neck where the blade joins the hub. Be very careful pushing these up above their
(very low) rated RPMs as they can explode (I have a scar to prove it)
Other options for increasing the lifting capacity:
While less efficient (one blade is the most efficient, but not practical), increasing blade surface area increases the air moved, and can increase lifting power
Again, inefficient, but redundant and a size-constrained way to increase power.
I'd also like to note that the lifitng capacity of 550 size multirotors is already quite high, and if you're toying with increasing that significantly, you're getting into dangerous territory. Care must be taken to ensure all of the systems can handle it. A blender strapped to a brick is no longer a toy