Preparation of high performance lithium-ion batteries with a separator–cathode assembly

Abstract

In this study, a novel separator–cathode assembly (SCA) comprising a positive electrode and a ceramic separator layer applied to this electrode is facilely prepared and investigated in lithium-ion batteries. The preparation of the SCA is performed by directly applying a suspension of polyvinylidene fluoride (PVDF)/Al₂O₃ (acetone as solvent) on the as-prepared cathode by a hot spray coating method, which can effectively prevent the adverse effects of the coating suspension on the microstructure of the electrode. Systematical investigations including morphology and structure characterization, water wettability testing and thermal resistance properties are carried out. The results indicate that the SCA possesses notable features, such as uniform and porous surface morphology, highly developed microporous structure, excellent wettability and thermal stability. Based on the above advantages, the cells assembled with SCA exhibit better electrochemical performances, such as the discharge C-rate capability and cycling performance, as compared to the commercialized PP separator. It is demonstrated that the SCA can availably improve the discharge performance and protect the battery from internal short, which is highly desirable for the development of high power/high energy lithium-ion batteries.