Honeycomb Spring
I saw this article (https://news.utexas.edu/2015/09/18/bouncing-back?utm_source=facebook&utm_medium=referral&utm_campaign=UTAustinNews) but no STL was provided, so I reverse engineered it real quick.
Experiment with your own sizes/parameters/design using the .blend file which has all of the building blocks of this spring ready to be manipulated.
The default thickness is 4mm, so scale Z accordingly.