Synthesis, structure, and ionic conductivity of Na5Li3Ti2S8

✍ Scribed by Fu Qiang Huang; Jiyong Yao; Zhanqiang Liu; Jianghua Yang; James A. Ibers

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 454 KB
• Volume: 181
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1016/j.jssc.2008.01.023

✦ Synopsis

The compound Na 5 Li 3 Ti 2 S 8 has been synthesized by the reaction of Ti with a Na/Li/S flux at 723 K. Na 5 Li 3 Ti 2 S 8 crystallizes in a new structure type with four formula units in space group C2/c of the monoclinic system. The structure contains three crystallographically independent Na + cations and two crystallographically independent Li + cations. Na 5 Li 3 Ti 2 S 8 possesses a channel structure that features two-dimensional 2 1 ½LiTiS 3À 4 layers built from Li(1)S 4 and TiS 4 tetrahedra. The layers, which are stacked along c, comprise eightmembered rings and sixteen-membered rings. Na(3) + cations are located between the eight-membered rings and Na(1) + , Na(2) + , and Li(2) + cations are located between the sixteen-membered rings. These cations are each octahedrally coordinated by six S 2À anions. The ionic conductivity s T of Na 5 Li 3 Ti 2 S 8 ranges from 8.8 Â 10 À6 S/cm at 303 K to 3.8 Â 10 À4 S/cm at 483 K. The activation energy E a is 0.40 eV.