Micron Size NaCrO 2 Particles Enable High-Loading Dry-Processed Electrode for Sodium Ion Batteries

Dry-process fabrication using fibrillatable binder is emerging as a promising method to produce high-loading electrodes for energy storage applications, favored by its cost-efficiency and eco-friendliness. While previous studies have demonstrated the advantages of dry process over the traditional slurry method, there remains a gap in understanding how the particle size of active materials influence the mechanical and electrochemical performance of dry electrodes. In this study, four different particle size NaCrO 2 materials (Average size, S-NCO: 0.6 µm, M1-NCO 1.5 µm, M2-NCO: 4.4 µm, and L-NCO: 9.9 µm) were synthesized to investigate the effect of particle size on dry-processed high-loading electrodes. Our findings reveal that the larger micro-sized (> 4.4 µm) NCO dry films exhibit significantly improved tensile strength and electrochemical performance, primarily ascribed to the low film porosity, abundant inter-particle connection by the binder, comprehensive carbon coverage, and efficient percolation of conductive pathway. Notably, a full cell incorporated with a high loading (5.2 mAh/cm²) and high active material ratio (96.5 wt.%) L-NCO film electrode demonstrates promising cycling stability and rate capability. These results provide valuable insights regarding the design and fabrication of dry-processed electrode for future energy storage applications. Figure 1