Scalable wet-slurry fabrication of sheet-type electrodes for sulfide all-solid-state batteries and performance enhancement via optimization of Ni-rich cathode coating layer

All-solid-state Li or Li-ion batteries (ASSLBs) have attracted much attention due to their potential high energy density, high safety, and low manufacturing costs compared to commercial liquid electrolyte Li-ion batteries. However, the rate capacity and cycling performance could not satisfy the practical application. Here, an island-like amorphous Li2O–ZrO2 (LZO) was coated on the surface of LiNi0.88Co0.10Al0.02 (NCA) via a sol-gel method and low-temperature sintering. The electrochemical performance and density functional theory calculation results demonstrate that the LZO coating layer significantly boosts Li-ions transfer. Targeting large-scale production, a sheet-type cathode was prepared by a wet-slurry process with PVDF-HFP as a binder, which exhibits an initial specific capacity of 181.91 mAh·g−1 at 0.13C and 25 °C. Remarkably, the wet-slurry cathode with a high NCA loading of 20 mg cm−2 delivers an initial areal capacity of 2.936 mAh·cm−2 and capacity retention of 69.93% after 1000 cycles at a rate of 0.64C. By employing X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy, we reveal that the LZO coating layer and PVDF-HFP binder inhibited the decomposition of sulfide electrolyte and detrimental structure evolution of NCA active material. This work would guide designing high-performance ASSLBs for practical application and commercialization.