Abstract
Recently, the demand for the middle- or large-sized lithium batteries with safety has increased. To solve this problem, all-solid state batteries (ASSBs) are actively researched. However, it is known that the ASSBs has a higher interfacial resistance than the conventional lithium batteries. Also, the ASSBs are operated at a high temperature of 60 to 80 °C, resulting in the degradation of the cycle performance due to the collapse of the structure of the active material.
In this study, NCM materials were coated with TiO2 via sol-gel process. The crystal structure and surface morphology were observed according to TiO2 content and calcination temperature using X-ray diffraction (XRD), Scanning electron microscope (SEM), and Transmission electron microscope (TEM). Moreover, ASSBs were fabricated by using the TiO2-coated NCM as cathode, composite electrolyte (CE) and lithium metal as anode. Electrochemical characteristics were evaluated on the all-solid cells at 70°C, 0.1C. As a result, it has been found that the lattice parameters and crystal size of the NCM bulk are affected by the sintering temperature and the TiO2 coating content, which also affects the discharge capacity and cycle characteristics of the cells. We describe about the electrochemical behavior of NCM coatings by TiO2 in ASSBs in more detail.