Constructing multi-functional Janus separator toward highly stable lithium batteries

Li dendrites, originating from the uneven deposition of Li+, could impale the separator and cause the short circuit in the battery, which seriously obstruct the application and development of lithium batteries, especially for lithium sulfur battery. Moreover, the intermediate polysulfides shuttling across the separator damages the capacity and corrodes the anode of lithium sulfur batteries, it is imperious to propose a settlement for the issues. Hence, we prepare a functional separator with asymmetric modification, which can block the growth of lithium dendrites and inhibit shuttle effect, simultaneously. On the one hand, Prussian blue (PB) barrier on the anode side increases the lifespan of the separator, and the uniform pore distribution of PB ensures the well-proportioned diffusion of Li+, and mitigates the growth of lithium dendrite. On the other hand, Prussian blue and reduced GO composites (PB/G) at cathode side could discourage polysulfides diffusion and enhance the conductivity of the battery. Benefiting from the above features, the full batteries with such modified separator reveal the high capacity of 1481 ​mAh g-1 at 0.1 C, and the capacity could maintain 744 ​mAh g-1 after 2000 cycles at 2 ​C.