Anomalies in Bulk Ion Transport in the Solid Solutions of Li7La3M2O12(M = Hf, Sn) and Li5La3Ta2O12

Publikation: Beitrag in einer FachzeitschriftArtikelBegutachtung

Abstract

Cubic Li7La3Zr2O12(LLZO), stabilized by supervalent cations, is one of the most promising oxide electrolyte to realize inherently safe all-solid-state batteries. It is of great interest to evaluate the strategy of supervalent stabilization in similar compounds and to describe its effect on ionic bulk conductivity σ′bulk. Here, we synthesized solid solutions of Li7-xLa3M2-xTaxO12 with M = Hf, Sn over the full compositional range (x = 0, 0.25..2). It turned out that Ta contents at x of 0.25 (M = Hf, LLHTO) and 0.5 (M = Sn, LLSTO) are necessary to yield phase pure cubic Li7-xLa3M2-xTaxO12. The maximum in total conductivity for LLHTO (2 × 10-4 S cm-1) is achieved for x = 1.0; the associated activation energy is 0.46 eV. At x = 0.5 and x = 1.0, we observe two conductivity anomalies that are qualitatively in agreement with the rule of Meyer and Neldel. For LLSTO, at x = 0.75 the conductivity σ′bulk turned out to be 7.94 × 10-5 S cm-1 (0.46 eV); the almost monotonic decrease of ion bulk conductivity from x = 0.75 to x = 2 in this series is in line with Meyer-Neldel's compensation behavior showing that a decrease in Ea is accompanied by a decrease of the Arrhenius prefactor. Altogether, the system might serve as an attractive alternative to Al-stabilized (or Ga-stabilized) Li7La3Zr2O12 as LLHTO is also anticipated to be highly stable against Li metal.

Originalspracheenglisch
Seiten (von - bis)16796-16805
Seitenumfang10
FachzeitschriftThe Journal of Physical Chemistry C
Jahrgang124
Ausgabenummer31
DOIs
PublikationsstatusVeröffentlicht - 6 Aug 2020

ASJC Scopus subject areas

  • Elektronische, optische und magnetische Materialien
  • Energie (insg.)
  • Physikalische und Theoretische Chemie
  • Oberflächen, Beschichtungen und Folien

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