LiCr(MoO4)2: a new high specific capacity cathode material for lithium ion batteries

Abstract

Molybdate polyanion cathode materials have received lots of research interest for their high specific capacity, high cycling stability and interesting physical and chemical properties. Here, LiCr(MoO₄)₂, a new deintercalation–intercalation type cathode material for lithium ion batteries, is synthesized and studied. Ultraviolet-visible-near-infrared diffuse reflection, density functional theory calculation and four-probe measurement results suggest that LiCr(MoO₄)₂ possesses a narrow band gap and high electronic conductivity. Bond-valence-sum maps calculation and electrochemical impedance spectroscopy prove the fast lithium ion transport rate of LiCr(MoO₄)₂. Benefiting from these advantages, LiCr(MoO₄)₂ delivers a high specific capacity (250 mA h g⁻¹) and good rate performances. The electrochemical reaction mechanism is studied by in situ X-ray diffraction, which indicates that the lithium ion deintercalation–intercalation is a solid solution process with Cr^3+/2+ and Mo^6+/5+ redox.