Dear All,
I have a question about Li handling in a glovebox under Ar atmosphere. I'm depositing Li films by PVD on Cu foils, the coater is integrated in a glovebox with inert Ar atmosphere. We have purifiers for moisture and O2, the sensors indicate a H2O concentration
The affinity of freshly deposited Li films to oxygen iis high compared to nitrogen and the fresh and porous Li will pick up oxygen easily, mainly in shape of O2 and H2O. Some glove box will be inefficient for excluding those. I suggest some vacuum load lock to the PVD chamber and being quick with all operations. Flowing dry nitrogen or argon and an efficient desiccant will help. Good luck from Heinrich!
Thanks a lot for your answer! Actually we controll the H2O and O2 concentration in the glovebox, but we can't control the N2 concentration. H2O and O2 are low (below 2ppm), and we do not see any contaminations in coatings handled in another glovebox with the same H2O and O2 concentrations than our glovebox, but having in addition the N2 purifier.
The Li coatings are deposited in vacuum (below 1e-6mbar) and then kept in vacuum as long as possible before taking them out in order to keep the exposure to the glovebox atmosphere as short as possible.
Yellow or black color seems to belong Li3N compound. Did you analyze your sample by another method, e.g., XRD, XPS ?
At this stage of discussion, it is clear that chemical analyses of the Li by XPS or ESCA are required. This should be possible at the ETH at Zürich. My personal bet on basis of working on aluminium PVD is: Some ill defined lithium oxide with a low carbon content as the top layer will be found. In my experience, such top layers tend to appear yellowish to brown. Basically, the oxide should be white/uncolored, but due to some optical effect the appearance may be more or less deep yellow.
Best from Heinrich
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