So are all sorts of terms, but in the sciences at least the rule is still that you introduce the full term and its acronym the first time it is used, before switching to the acronym for the rest of the paper. Sure, everyone doing electrochemistry knows what EIS means, but you still write "electrochemical impedance spectroscopy (EIS)" before you go on.

You can adjust the strictness for audience and intent perhaps, but it's still sloppy not to.