If you open the ExampleFiles-ObjectsLink.html file in the example files folder of your EnergyPlus installation (e.g. C:\EnergyPlusV9-5-0\ExampleFiles), you will find a table of EnergyPlus object types and what example file(s) showcases them. For the Generator:FuelCell object, there appears to be two example files:

• MicroCogeneration.idf: SOFC (solid oxide fuel cell) as baseload cogenerator with a combustion microCHP in a small food service building
• _FuelCellTest200.idf: not found in example files folder (this may be a test IDF for the EnergyPlus development team)

While there isn't an example file for PEMFC (solid oxide fuel cell), the Input-Output Reference section for the fuel cell object that I linked to above does mention this:

The model can be used for two general types of fuel cells, solid oxide fuel cells (SOFC) and proton exchange membrane fuel cells (PEMFC).

So, it can be done. The only input field description of the fuel cell object that mentions SOFC vs. PEMFC is the Stack Cooler Name of a Generator:FuelCell:StackCooler object (this is required for PEMFC).