An electrode including micro-sized secondary particle (MSSP) with enhanced ionic conductivity for solid-state battery is provided. The MSSP comprises a cathode particle and a solid-state electrolyte. The cathode particle is at least partially coated by solid-state electrolyte. The lithium ion transport inside the micro-sized secondary particles is increased by the incorporation of solid-state electrolyte. The electrode can be prepared by casting the slurry comprising MSSP, another electrolyte, binders, and conductive additives on the current collector. The current collector is comprised of a conductive material. The current collector has a first side and a second side. The electrode active material layer is disposed on one of the first and second sides of the current collector.