Preparation and Properties of High-Loading Solvent-Free Dry Electrodes in LiFePO₄ Lithium-Ion Batteries

In this paper, solvent-free, high-loading graphite (Gr) electrodes (single-sided electrode areal density of 26.8 mg cm^-2) and high-loading LiFePO₄ (LFP) electrodes (single-sided electrode areal density of 53.8 mg cm^-2) are prepared by a dry processing method of powder dry mixing and calendering, whose microstructural homogeneity is optimized to enhance lithium-ion transport in pore channels, thus showing lower tortuosity. Dry electrodes exhibit a cycle stability and rate performance similar to those of low-loading Wet electrodes in half cells. In addition, the Dry LFP electrode exhibits lower polarization and a high Li-ion diffusion coefficient (D_Li⁺), and the Dry LFP electrode (areal capacity: 8.4 mAh cm^-2) and Dry Gr electrode (areal capacity: 9.0 mAh cm^-2) have good cycling stability in coin and single-layer pouch full cells. The capacity retentions are 68.37 and 75.82% after 200 cycles at 0.2C and after 60 cycles at 0.5C, respectively. This work emphasizes the great potential of the innovative solvent-free dry processing method as a production route for advanced high-capacity LFP lithium-ion batteries due to the advantages of its high-loading ability, good environment, and cost savings.