Li3Mo4P5O24: A two-electron cathode for lithium-ion batteries with three-dimensional diffusion pathways

The structure of the novel compound Li3Mo4P5O24 has been solved from single crystal X-ray diffraction data. The Mo cations in Li3Mo4P5O24 are present in four distinct types of MoO6 octahedra, each of which has one open vertex at the corner participating in a Mo═O double bond and whose other five corners are shared with PO4 tetrahedra. On the basis of a bond valence sum difference map (BVS-DM) analysis, this framework is predicted to support the facile diffusion of Li+ ions, a hypothesis that is confirmed by electrochemical testing data, which show that Li3Mo4P5O24 can be utilized as a rechargeable battery cathode material. It is found that Li can both be removed from and inserted into Li3Mo4P5O24. The involvement of multiple redox processes occurring at the same Mo site is reflected in electrochemical plateaus around 3.8 V associated with the Mo6+/Mo5+ redox couple and 2.2 V associated with the Mo5+/Mo4+ redox couple. The two-electron redox properties of Mo cations in this structure lead to a theoretical ...