New Solid Electrolyte Li8– xZr1 –xTaxO6 (x = 0–0.5) for Lithium Power Sources

Abstract

In the work, new lithium-conducting solid electrolytes based on lithium zirconate are synthesized. They are obtained by doping Li₈ZrO₆ phase with isostructural Li₇TaO₆. It is shown that in the Li_{8– x}Zr_{1– x}Ta_xO₆ system, a series of solid solutions х = 0−0.5 based on Li₈ZrO₆ form. The conductivity of synthesized Li_8 ‒ xZr_{1 – x}Ta_xO₆ solid solutions increases by 1–2 orders of magnitude as compared with undoped zirconate Li₈ZrO₆ due to the formation of lithium vacancies in the tetra- and octahedral layers of the structure. All-solid-phase electrochemical cells with Li_7.85Zr_0.85Ta_0.15O₆ electrolyte, 0.75Li₂SnMo₃O₁₂ ∙ 0.25B₂O₃ glass-ceramic anode, and 0.2Li₂O · 0.2LiF · 0.45V₂O₅ · 0.25B₂O₃ cathode are electrochemically tested. It is shown that the resistance of 0.75Li₂SnMo₃O₁₂ · 0.25B₂O₃|Li_7.85Zr_0.85Ta_0.15O₆|0.2Li₂O · 0.2LiF · 0.45V₂O₅ · 0.25B₂O₃ cell decreases after the charge—discharge cycling.