Synthesis and conductivity of new lithium-containing Nasicon-type phases: Lix[MxIIM2 –xIII](SO4)3 –y(SeO4)y and Lix[Lix/2M2 –x/2III](SO4)3 –y(SeO4)y

Abstract

The synthesis of new phases Li_x[M_x^IIM_{2 –x}^III](SO₄]_{3 –y}(SeO₄)_y and Li_x[Li_x/2M_{2 –x/2}^III](SO₄)_{3 –y}(SeO₄)_y, with the nasicon structure is reported. The ionic conductivities of a range of samples have been measured, with the highest conductivity (σ₄₃₇= 1.6 × 10^–4Ω^–1 cm^–1) being observed for Li_0.5[Mg_0.5Fe_1.5](SO₄)₃. Attempts to increase the Li content by partially replacing the (S,Se)O₄ groups by PO₄ or SiO₄ have proved unsuccessful. The synthesis of mixed Na- and Li-containing samples is also reported.