Direct fabrication of thin-film LiTi2(PO4)3 electrodes using the hydrothermal method

In this study, the thin-film solid electrode LiTi2(PO4)3 (LTP) was in-situ fabricated and sequentially deposited on a substrate using a hydrothermal method. The results suggest that crystals of the LTP film evolve from whisker clusters to cubes and that the crystalline region nucleates at the interface with the substrate and grows outwards. After a 48-hour reaction, the cubic-shaped LTP crystals formed a dense LTP film with few pores and peeling or flaking at the interface with the substrate. However, the cubic-shaped solid electrolyte is not favourable for charge transfer and Li+ ion diffusion, resulting in a poor ionic conductivity of approximately 1.0 × 10− 7 S/cm. Fortunately, the hydrothermal process offers a possible method for doping the Al3 + into the LTP film, and the ionic conductivity increases to as higher as 1.4 × 10− 5 S/cm as a result of the modified LTP grain boundary. This study demonstrates that hydrothermal technology is a potential method for fabricating thin-film lithium battery materials.