Study of the tritium behavior on the surface of Li2O by means of work function measurement

In the present study, the work function change of Li2O due to change of oxygen potential of sweep gas was investigated by measuring the contact potential difference (CPD) between Li2O and Pt electrodes with a so-called `high temperature Kelvin probeʹ. The CPD change for Li2O was generally insensitive to the oxygen partial pressure in the sweep gas. A similar insensitivity was also observed for LiAlO2. Although the CPD change of Li2O was about 200 mV when the oxygen partial pressure was changed by as much as 15 orders of magnitude, such was not the case for LiAlO2. By comparing with the results obtained for other Li-bearing ceramics, it was estimated to be caused by the adsorption/desorption processes of water vapor contained in the sweep gas.