Benchmarking the Performance of Moisture-Sensitive Battery Materials: the Importance of the Electrode Preparation Method

Many promising electrode materials for next-generation batteries are moisture-sensitive, resulting in various challenging issues. Here, we demonstrate the vital importance of the electrode preparation method in benchmarking their performance reliably using the O3-type NaNi 1/3 Fe 1/3 Mn 1/3 O 2 (NFM111) as a model material. We show that the conventional slurry-based method leads to poor-quality electrodes, whereas those prepared by a dry method in argon exhibit a remarkable capacity which is significantly higher than previously reported values, highlighting that the energy density of layered sodium cathodes has been systematically underestimated. Collectively, we propose a general electrode preparation protocol for benchmarking moisture-sensitive battery materials.