Freestanding layer-structure selenium cathodes with ultrahigh Se loading for high areal capacity Li-Se batteries

Abstract In this work, a freestanding layer-structure Se cathode, composed of alternant barrier layers and active layers, is synthesized via a facile syringe-filtration strategy. With employing the barrier layers simultaneously acting as polyselenide-interception barriers and as highly conductive current collectors, the active layers with 3D porous architecture are endowed with strong polyselenide-trapping capability and fast redox-conversion capability. Such novel Se cathode readily achieves a high Se loading up to 13.5 mg cm −2 . The optimized Se cathode with a high Se loading of 4.5 mg cm −2 exhibits high specific capacity/areal capacity (794 mA h g −1 /3.6 mA h cm −2 ), excellent cycling stability (508 mA h g −1 @300 cycles), and remarkable rate capability (389 mA h g −1 @800 mA g −1 ), which is superior to conventional Se cathodes.