Rapid and energy-efficient synthesis of disordered rocksalt cathodes

Lithium-rich transition metal oxides with a cation-disordered rocksalt structure (disordered rocksalt oxides or DRX) are promising candidates for sustainable, next-generation Li-ion cathodes due to their high energy densities and compositional flexibility, enabling Co- and Ni-free battery chemistries. However, current methods to synthesize DRX compounds require either high temperature (≈1000 °C) sintering for several hours, or high energy ball milling for several days in an inert atmosphere. Both methods are time- and energy-intensive, limiting the scale up of DRX production. The present study reports the rapid synthesis of various DRX compositions in ambient air via a microwave-assisted solid-state technique resulting in reaction times as short as 5 min, which are more than two orders of magnitude faster than current synthesis methods. The DRX compounds synthesized via microwave are phase-pure and have a similar short- and long-range structure as compared to DRX materials synthesized via a standard solid-state route, resulting in nearly identical electrochemical performance. In some cases, microwave heating allows for better particle size and morphology control. Overall, the rapid and energy-efficient microwave technique provides a more sustainable route to produce DRX materials, further incentivizes the development of next-generation DRX cathodes, and is key to accelerating their optimization via high-throughput studies. (© 2023 The Authors. Advanced Energy Materials published by Wiley‐VCH GmbH)