Designing a High-Energy Dry-Processed Electrode for Li-Ion Batteries By Layering Single-Walled Carbon Nanotubes Onto the Ni-Rich Cathode Material

With the growing need for lithium-ion batteries (LIBs) in the context of carbon-neutral policies, the requirements for high safety and high energy density in LIBs have gained importance. High-nickel-content (Ni≥90%) cathodes offer a means of increasing both volumetric and gravimetric energy densities, but they also increase the risk of structural instability, which jeopardizes the battery system's overall safety. Thus, it makes more sense to maximize electrode packing density while using stable cathode materials. To mitigate these issues, we apply a coating material of single walled carbon nanotubes (SWCNTs) on the surface of the LiNi0.85Mn0.07Co0.05Al0.03O2 cathode, thereby significantly increasing its electronic conductivity. Furthermore, to increase ionic conductivity of the SWCNT-coated NCMA cathode, we also adopted a solvent-free electrode fabrication procedure. Our SWCNT-dry electrode showed sustained electrochemical characteristics in addition to a notably high cathode material weight ratio (99. x (x=0.5, 0.7, 0.9) wt.%) and increased electrode density (4.0 g cm−3). Their superior volumetric capacity of 860 mAh cm−3 allowed them to surpass traditional wet-processed electrodes (The first group consists of NCMA, CB, and PVDF, mixed in a ratio of 96:2:2, achieving an electrode density ≈ 3.4 g cm−3 and second group consists of NCMA, CB, and PVDF, mixed in a ratio of 98:1:1 achieving an electrode density ≈ 3.6 g cm−3). SWCNT coating combined with a solvent-free electrode is a novel technique that could lead to significant improvements in LIBs' high energy density, industrial scalability, and cell safety.