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

## TL;DR

A green, low-temperature method is developed to synthesize recyclable cation-disordered Li3VO4 for high-rate battery anodes.

## Contribution

A one-pot synthesis of cation-disordered Li3VO4 below 40 °C using standard lab equipment is demonstrated.

## Key findings

- Cation-disordered Li3VO4 is synthesized at <40 °C using a rotary evaporator and vacuum dryer.
- The material is kinetically stabilized but undergoes a moisture-induced phase transition to a less effective β-phase.
- The material is water-soluble and can be reverted to its precursor ions, showing recyclability.

## 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.

The methodology supports the development of innovative materials that simultaneously achieve green chemistry and high performance.