Dumb question, but can't we put some giant blocks of single-piece kevlar-ish material in orbit? I imagine they would have no chance for breaking apart and would just serve as "bullet" catchers for these small pieces of debris.
https://en.wikipedia.org/wiki/Hypervelocity
The orbital velocity needed to maintain a stable low Earth orbit is about 7.8 km/s, but reduces with increased orbital altitude.