Electrochemical intercalation of alkali metals into superconducting oxide phases

Abstract

The electrochemical intercalation of alkali metals into several superconducting oxide phases has been carried out by galvanostatic discharge of an electrochemical cell. In each case intercalation appears to result in a decrease in the volume fraction of the superconducting phase. Intercalation of lithium into an indium-doped Bi–Sr–Ca–Cu oxide gave a material of approximate composition Li_0.23Bi_1.9In_0.1Sr₂CaCu₂O_{8 +δ}, in which the superconducting onset temperature, T_c, was increased by ca. 15 K above that of the original compound. Intercalation into other superconducting bismuth oxides produced increases in T_c in some cases, and decreases in others. Intercalation into the thallium 2212 superconductor produced no discernible change in T_c.