Electrode objects with negative voltage

Hi all!
While browsing the Battery Explorer I stumbled across some electrodes with a negative calculated average voltage. I was wondering what was going on with these entries: is there an error in the calculations upstream? It seems difficult to me that TM oxides could have redox potentials below the one of Li+/Li, provided that this is the actual zero value.

A couple examples I found: [mp-1176726_Li], [mp-246_Na]

Hi @acarnevali, it is possible within our present definition of intercalation electrodes to see negative energies since we are only looking at pairs in the topotactic subset of materials:

If you are seeing negative voltages that you don’t expect this could be due to that particular chemical subspace (Fe2O3 + Li_x for example) being undersampled. Or it could be due to the fact that the Tolerances for structure matching were too high and a higher voltage (lower Li/ no Li) structure was missed.

If you grab the structures, from the entries you can use the following code to structure match them together and play around with the tolerances:

However, for the Fe2O3 material, there does seem to be some rendering problems:

Just gonna ping some people here about it

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