High-energy density ultra-thick drying-free Ni-rich cathode electrodes for application in Lithium-ion batteries

Abstract

Lithium-ion batteries (LIBs) can be considered as one of the pivotal components required to succeed in the drive towards a greener future. However, the current processing methods for the cathode electrode make it harmful and costly due to the toxic solvent drying and recovery stages. Additionally, the reliance on LIBs particularly emphasizes the imperative for increased energy density in both volume and weight, which predominantly relies on the cathode. To surmount these challenges, this research analyses the true requirements of a novel process and introduces a novel solvent-assisted binder (SaB) dry electrode approach to satisfy them. This innovative method incorporates a low-boiling point and relatively non-toxic solvent (ethanol) at less than 3 wt.%, enhancing the processability of the electrode without compromising safety, cost reductions, or environmental impact associated with traditional dry processes. The SaB process allows the calendaring to cause less damage to the electrode thanks to the binder distribution and allows for better fibrillization of the binder, improving the electrode microstructure. Over 100 cycles at 1C, the SaB dry electrode achieves 77.70% capacity retention, surpassing the standard dry electrode's 72.39% at a loading of approximately 30 mg cm−2 and is also capable of performing at ultra-high loadings up to 60 mg cm−2.