Electrochemical intercalation of lithium in layered niobates AB(2)Nb(3)O(10) (A = K, Rb, Cs; B = Ca, Sr) and their superconductivity

摘要

We have succeeded in preparing Li-intercalated layered niobium oxide Li(x)AB(2)Nb(3)O(10) (A = K, Rb, Cs; B = Ca, Sr) by an electrochemical technique. The host compounds AB(2)Nb(3)O(10) were synthesized by a solid state reaction method at 850-1150 degreesC for 10-12 h. All of the intercalated compounds showed superconductivity at 4-6 K. In the cases of A = Rb, B = Ca, and A = Cs, B = Ca, no superconductivity appeared up to x = 0.17, for x = 0.34 and 0.46 T-c was constant with maximum value. and for x = 0.62 T-c decreased slightly. On the other hand, the correlation between T-c (onset) and a-axis length demonstrates that T-c tends to increase with a-axis length increasing, which was found in Li(0.34)AB(2)Nb(3)O(10) with optimum Li content. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 5]