Highly efficient synthesis of titanium phosphate precursor for electroactive materials

Abstract

In recent years titanium phosphates (TiPs) have aroused considerable interest as multi-functional materials. Known methods of TiPs synthesis are rather complicated because they are based on wet chemistry in terms of which one-step synthesis of pure TiP fails. It is highly welcomed to develop a new approach to TiP production. In this work the novel minimalistic approach to the synthesis of two titanium phosphates of different composition from a solid TiOSO 4 ·H 2 O precursor has been proposed. Despite the fact that the TiOSO 4 solutions are widely used for the synthesis of titanium phosphates, the solid compound as a titanium source has never been used before. The new mechanochemistry-based synthesis provides easy access to obtaining TiO(OH)(H 2 PO 4 )·H 2 O and Ti(HPO 4 ) 2 ·H 2 O (α-TiP) for 3 h and 5 h, respectively. The substitution of protons in α-TiP with Li + and Al 3+ by ion-exchange reactions provide the formation of Li 1.5 Al 0.5 Ti 1.5 (PO 4 ) 3 which is electroactive material. The proposed synthesis procedure is more technologically attractive compared with traditional methods, and enables direct production of highly dispersed monophasic powder (100–300 nm) of desired composition at 823 K. The material obtained demonstrates high conductivity value of 7.8·10 −4 S cm −1 at 298 K, low activation energy of 0.27 eV, and can be used as a solid electrolyte for practical application in all-solid-state lithium batteries.