Binderless Dry Cathode Using a Nanoparticle Deposition System for Lithium-Ion Battery Applications

Binder-free dry cathodes are in high demand because they can significantly reduce production costs by eliminating solvent removal and recovery processes and increase energy density by eliminating the need for binders, which are electrochemically inactive materials. To address these critical challenges, to the best of our knowledge, this study is the first to propose and introduce a nanoparticle deposition system (NPDS) for producing binder-free dry cathodes for lithium-ion batteries. The NPDS process produces films via supersonic acceleration of the powder, followed by collision with the substrate, using a simple pressure difference between the spraying nozzle and deposition chamber. This method facilitates the fabrication of dry films using commercial powders without the need for binders as the particles are directly deposited onto the substrate. By optimizing the process parameters, binder-free dry cathodes using LiNi_0.9Co_0.05Mn_0.05O₂ were successfully developed, and their properties were compared with those of wet slurry-coated cathodes. Tape tests confirmed that the dry cathode exhibited better adhesion between the cathode materials and Al foil than the wet cathode. Further, the dry cathode exhibited better discharge capacity, rate capability up to 20 C, and cyclability exceeding 200 charge/discharge cycles compared to the wet cathode. Specifically, the dry cathode experienced only a 38% reduction in its initial capacity following 200 cycles owing to strong adhesion, whereas the wet cathode degraded by 56%, with significant material peeling from the Al foil. Consequently, due to this enhanced adhesion, the dry cathode exhibited greater discharge capacity, rate capability, and cyclability than the wet cathode. Therefore, this study successfully demonstrated the potential of NPDS for producing binder-free dry cathodes, thereby laying the groundwork for the development of advanced binder-free dry cathodes.