Minimizing the Reaction Heterogeneity in Ultrafast Joule Heating Synthesis of Disordered Rocksalt Cathodes

Developing lithium-ion battery cathode materials that are not constrained by resource availability represents a promising direction for future development. Due to their extensive chemical space, lithium-rich cation-disordered rock-salt (DRX) cathodes hold significant potential for next-generation resource-abundant cathode materials. Typically, synthesizing DRX requires several hours of high-temperature sintering. However, conventional sintering methods involve slow heating rates, prolonged durations, and high energy consumption, which are incompatible with the goals of renewable energy development, high energy efficiency, and sustainability. In this study, we focus on evaluating and optimizing the rapid synthesis method for DRX cathodes based on Joule heating. Our investigation emphasizes the critical influence of amorphous phase content, crystallinity, and elemental homogeneity on the performance of DRX synthesized via Joule heating. Insufficient sintering time can hinder the incorporation of amorphous lithium into the DRX lattice, resulting in suboptimal capacity. Additionally, crystallinity and elemental distribution uniformity significantly impact electrochemical performance and stability. By optimizing the synthesis protocol and reaction parameters, we achieved performance comparable to traditional solid-state methods while reducing energy consumption by 3 orders of magnitude. This work demonstrates the combination of cost-effective DRX cathodes with a more energy-efficient Joule heating synthesis method, highlights critical considerations that must be paid attention to during the synthesis, and offers valuable insights for advancing a greener and more sustainable battery industry.