Hydrothermal synthesis of lepidocrocite-like potassium lithium titanate K0.80Li0.267Ti1.733O4 (KLTO) with superior polarization performance

Lithium potassium titanate (K0.80Li0.267Ti1.733O4, abb.as KLTO) was an important layered material which was widely used as anode materials in battery applications. As the most popular approach for KLTO production, the systematic investigation on the formation mechanism under hydrothermal synthesis conditions is missing, which would delay further development of the method in a wide application. In this work, the synthesis mechanism of KLTO under hydrothermal conditions was systematically investigated by both experimental observations and theoretical calculations. It was observed that factors including titanium dioxide particle size, reaction time/temperature, and KOH/LiOH amount affected the phase purity of obtained KLTO, while the amount of LiOH played the critical role. It was attributed to the beneficial effects of LiOH on the formation of loose structure as well as the hydration of TiO2 structure, which further favored K+ insertion to have the perfect KLTO crystal as identified by DFT and IRI calculations. A completely new application of KLTO as absorbing material was explored due to its superior polarization performance including dielectric permittivity, electromagnetic wave absorption, and electrorheological properties. DFT calculations over charge difference distribution further argued the promotion effect of Li element on polarization performance. This work paves the way to synthesize perfect KLTO under hydrothermal conditions while lighting its future application as absorbing material with further study.