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  Tonti, D.; Pettenkofer, C.; Jaegermann, W.: Origin of the electrochemical potential in intercalation electrodes: experimental estimation of the electronic and ionic contributions for Na intercalated into TiS₂. The Journal of Physical Chemistry B 108 (2004), p. 16093-16099

10.1021/jp047450o

Abstract:
see jps.tonti.pdf