1The presence or absence of an MPL had no influence on the performance degradation in similar irradiation experiments at 303 K.

2Owing to a programming error, the beam-off periods after the fifth to the seventh irradiation period of the 10% beam intensity irradiation experiment were exceptionally reduced to 10 s.

3Compared with the electrochemical losses of the cell of about 300 mW cm-2 already, the absorbed X-ray energy of the full beam intensity seems negligible for cell heat-up.