The effects of lattice volume and carrier concentration on the conductivity of NASICON-type LiXIn0.5Z0.5(PO4)3 (X = Ti, Zr; Z = Nb, Ta) oxides

Autor: Yue Jin Shan, Nooradzirah Binti Abdul Rashid, Keita Sugawara, Keitaro Tezuka
Rok vydání: 2021
Předmět:
Zdroj: Ionics. 27:3829-3835
ISSN: 1862-0760
0947-7047
Popis: Novel NASICON-type LiXIn0.5Z0.5(PO4)3 (X = Ti, Zr; Z = Nb, Ta) oxides were successfully synthesized by solid-state reaction, and resultant crystal structures (space group R-3c) and ionic conductivities were investigated based on a scheme of changed unit cell volume but an unchanged nominal carrier concentration (or constant Li+ amount). Relative to unsubstituted LiX2(PO4)3, the conductivities of all samples were improved by approximately an order of magnitude, with LiTiIn0.5Ta0.5(PO4)3 sample showing the highest value of 2.5×10-6 S cm-1 at room temperature. The improvement in ionic conductivity of Ti-containing samples is considered due to an increase in unit cell volume caused by the larger size of substituted ions (In3+, Nb5+, or Ta5+). Conversely, the improvement in ionic conductivity of Zr-containing samples may be attributed to an increase in lithium ion migration caused by a repulsion between the lithium ion and its surrounding cations (Zr4+, In3+, or Nb5+/Ta5+) in a smaller unit cell volume, thus forming a weakened Li-O bond.
Databáze: OpenAIRE
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