How to speed up my research as a PhD student?
In many disciplines, research amounts to an endless series of frustrations, setbacks, and failures punctuated by the occasional success. So while it’s not necessarily true that there’s a slowdown in the middle, it’s usually the case that there are periods of lower output than others.

The only projects that go smoothly from start to finish have either been extremely lucky or tend to be development-based or “following on” from someone else’s struggles. So don’t be discouraged by having a period of relatively fallow productivity—it happens to nearly everybody. It’s a sign that your problem is non-trivial and requires some work and effort to complete successfully.

As for “speeding it up,” I don’t think that’s really possible to do by scanning papers instead of reading them. It’s hard to make specific suggestions without knowing more about the discipline, but productivity in research can be elusive at times, and there really isn’t anything you can do to accelerate things, unless you can somehow try more different solutions during your workday. So perhaps it’s a matter of having fewer distractions and disruptions to your day.