Lithium intercalation into the tetradymite-type selenides Bi_2-xIn_xSe₃

Abstract

Electrochemical intercalation of Li⁺ ions into Bi_2-xIn_xSe₃ crystals (x = 0·0, 0·01, 0·22 and 0·46) has been studied. According to the cyclic voltammograms obtained during the first charge-discharge cycle, the amount C of intercalated Li⁺ ions depends on the concentration x of In in the crystals; maximum intercalation was observed for the crystals with x = 0·01. The observed dependence of C = f(x) is similar to the concentration dependences of the Hall coefficient, electric conductivity and Seebeck coefficient, that is to the dependence of the concentration of free charge carriers on the concentration of In in the crystals. From an analysis of the relations between intercalation properties and the nature of point defects in Bi_2-xIn_xSe₃ crystals it was concluded that changes in the concentration of Se vacancies V^⋅⋅ _Se are responsible for the observed changes in the intercalation properties of the Bi_2-xIn_xSe₃ crystals.