Figure 1 illustrates the photograph of the as-prepared ceramic membrane which perfectly retained its shape and size even after swelling with the liquid electrolyte solution. Figure 2a, b (SEM images) reveals the surface morphology of the ceramic membrane at two different magnifications. It can be seen that the ceramic particles are homogeneously he. The characteristics at the lithium metal–electrolyte separator interface critically influence the long-term cell performances such as cyclability, cycling performance at high rate and safety. Although lithium metal possesses a very high theoretical specific capacity of 3,860 mA g−1, its thermodynamic instability leads to the formation of a solid el. In order to explore the applicability of the ceramic membrane as Li-ion battery separator, after activation by soaking in the non-aqueous LiPF6-based liquid electrolyte, it was assembled in a lithium cell having the composition Li/CM/LiFePO4, as described in the experimental section, and the results are shown in Fig. 6a, b. In particular, plot (a).