Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7439997/

If the binding energy is low, it means that the particles are not as strongly bound together, and it is therefore easier to separate them. A high binding energy means that the particles are more strongly bound together, and it is therefore more difficult to separate them.ACE2 is the first receptor SARS-CoV-2 uses to bind to a cell