Syntheses, structure and properties of new A_3-xMn_yTi_4-yO₉(A=Na, Li) with a tunnel structure

Abstract

A new compound Na_2.7MnTi₃O₉ with the Na_3-xTi₄O₉-type tunnel structure was synthesized by solid-state reaction at 1173K. It crystallizes in the monoclinic system, space group C2/m, and lattice parameters of a = 2.301 nm, b = 0.2918 nm, c = 1.068 nm, β= 102.9. We have also successfully prepared the isostructural compound Li_2.7MnTi₃O₉ by the ion-exchange technique in the molten LiNO₃ salt. The electrochemical lithium extraction and insertion properties of the obtained Li_2.7MnTi₃O₉ were examined.