Phase formation and dielectric properties of ultralow temperature sintered Li4Mo5O17 ceramics

The Li2MoO4-MoO3 ceramic system can be densely sintered at ultralow temperatures (< 500 °C). However, the phase composition of the Li2MoO4-MoO3 system at a molar ratio of 1:1 has always been controversial. In this study, the traditional solid-state method was used to synthesize Li4Mo5O17 (400 °C, 10 h) and Li2Mo2O7 (350–400 °C, 4 h). Li2Mo2O7 is an intermediate phase that can be converted to Li4Mo5O17 at higher temperatures. The Li4Mo5O17 ceramic could be sintered and densified at only 490 °C in air, exhibiting a relative density of 95.6% and excellent dielectric properties, including ε′= 12.79 and tan δ = 0.0004 at 1 GHz. Such an ultralow sintering temperature and dielectric loss indicate that the Li4Mo5O17 ceramic is a good candidate for high-frequency capacitance applications.