Green one-pot synthesis of recyclable cation-disordered Li3VO4 below 40 °C for high-rate anode materials

Abstract

To advance a sustainable society, increasing attention has been directed toward the development of high-performance materials and environmentally responsible synthetic methodologies. Cation-disordered materials have attracted attention across various fields because of their exceptional performance. However, their synthesis requires high-temperature calcination or after-treatment of cation-ordered precursors, resulting in high energy consumption levels, extended processing times, and increased costs, which hinder commercialization. Recently, low-temperature solution-based reactions enabling the synthesis of cation-disordered structures via instantaneous crystallization using spray dryers have been reported; however, technical insights into these processes remain unclear due to very few reports compared with those for solid-state reactions. In this study, we demonstrate low-temperature one-pot synthesis (<40 °C) of cation-disordered Li₃VO₄, a high-performance anode material, from a solution reaction via a combination of a rotary evaporator and a vacuum dryer, which are standard laboratory apparatuses, under strictly controlled conditions. This cation-disordered Li₃VO₄ is identified as a kinetically stabilized metastable phase and undergoes a moisture-induced phase transition to the thermodynamically stable β-phase, which results in inferior performance. Moreover, it can be dissolved in water and reverted to its precursor ions, indicating its recyclability. This methodology, in which a kinetically stabilized crystal phase is synthesized via evaporation-driven crystallization, supports the development of innovative materials that simultaneously achieve green chemistry and high performance.