Local structure in LiTa2PO8 based electrolytes

Lithium tantalum phosphate LiTa2PO8 is a new Li+ ion conducting solid electrolyte that shows high room temperature Li+ ion conductivity, which can be further enhanced by Si doping [Li1+xTa2P1-xSixPO8]. Although the average structure of LiTa2PO8 has been well determined, there is little knowledge of the local structure, in particular, whether defect clusters of Li+-ion interstitials are formed in this system and how these relate to the conduction mechanism. High resolution 31P solid state NMR results suggest a number of local structural motifs are present. A total neutron scattering study of this system is proposed to establish details of the local structure and how this varies with composition. The results will be used to establish details of the conduction mechanism in this important new electrolyte.