Electrochemistry indirectly imports both emmo 1.0.0-beta3 and 1.0.0-beta4.
The issue is that the modules computerscience_bigmap, isq_bigmap and units_bigmap explicitely imports emmo 1.0.0-beta3, while module electrochemicalquantities imports computerscience_big_map, which in turn import emmo 1.0.0-beta4.
My recommendation is to upgrade to emmo 1.0.0-beta4.
I've submitted a pull request to emmo-1.0.0beta4 to include most of the ISQ quantities. Once that is merged, we should import beta4 into electrochemical quantities and eliminate the generic concepts layer. In the future, generic concepts should be handled as pull requests into emmo.