Enhanced Electrochemical and Transportation Properties in a NASICON-Type Na3Zr2(SiO4)2(PO4)–Na3Ti2(PO4)3 Junction Prepared by Spin Coating and Glass-Ceramic Processes

Impacts of an electrode active material with 1 μm scale thickness on the performance of an oxide-based all-solid-state battery (ASSB) have been investigated by metallic Na | Na3Zr2(SiO4)2(PO4) (NZSP) | Na3Ti2(PO4)3 (NTP) cells. Dense crystalline NTP layer is formed on NZSP ceramic electrolyte using spin coating of glass powder suspension and subsequent crystallization (glass-ceramic process). A sample with 0.6 μm thick NTP layer exhibits 0.1 C charge/discharge cycling with very small polarization (80% after 60 cycles. Fast cathode kinetics also realized the 0.1 C capacity at −20 °C to be ∼80% retention. Furthermore, a facile control over the thickness of cathode films without any conductive additives in the 1 μm range demonstrated in this work enables the assessment of cathode kinetics. Electrochemical impedance spectroscopy revealed that Warburg resistance originates from an ambipolar diffusion of an electron and Na+ ion. The methodology presented here paves a way for rapid examinations of electrode material compatibility and electrode design for next-generation oxide-based ASSBs.