Electrochemical Modification of Superconductive Oxides

Abstract

The electrochemical potential between highly electropositive cations and conductive oxides has been the basis for numerous electrochemical batteries (Li/MnCO₂, Li/V₂O₅). A new cell, based on the superconductive oxide, YBa₂Cu₃O_x, as a cathode and lithium as an anode, has been developed. The cell exhibited high open-circuit voltage (2.8 volts) and long-term loaded voltage stability under low drain conditions at room temperature. The cell was discharged four months before destructive analysis. Room temperature operation was initially performed due to the use of a liquid electrolyte.

This initial work evaluated the effect of lithium interaction with the superconductive properties of the reacted cathode. No shift in transition temperature (93°K) has been observed in the lithium reaction YBa₂Cu₃(Li_0.87)O_x (x~6.7), although all superconductive properties were lost within two weeks after exposure to ambient conditions. No new phases were identified, indicative of lithium intercalation into the superconductor structure. This technique allows controlled introduction of cations species (Li⁺, Ca⁺⁺, etc.) into a superconductive oxide structure for property modification studies.