▎ 摘　　要

NOVELTY - Graphene foam-protected selenium cathode layer for an alkali metal-selenium cell comprises (a) a sheet or a roll of solid graphene foam composed of multiple pores or cells and pore walls containing graphene sheets, where the graphene sheets contain a pristine graphene material having less than 0.01 wt.% of non-carbon elements or a non-pristine graphene material having 0.01-20 wt.% of non-carbon elements, the non-pristine graphene is graphene oxide, reduced graphene oxide, graphene fluoride, graphene chloride, graphene bromide, graphene iodide, hydrogenated graphene, nitrogenated graphene, boron-doped graphene, nitrogen-doped graphene and/or chemically functionalized graphene, and the graphene sheets are interconnected or chemically merged together without an adhesive resin, and (b) selenium coating or particles residing in the pores or bonded to the pore walls of the solid graphene foam. USE - The graphene foam-protected selenium cathode layer is used in the alkali metal-selenium cell and the alkali metal-selenium battery which is used as a rechargeable lithium-selenium cell, sodium-selenium cell, potassium-selenium cell, lithium ion-selenium cell, sodium ion-selenium cell, or potassium ion-selenium cell (all claimed). ADVANTAGE - The graphene foam-protected selenium cathode layer: exhibits higher thermal conductivity as compared to both mesophase pitch-derived graphite foam and nickel foam template-assisted chemical vapor deposition graphene, given the same physical density; provides the rechargeable lithium-selenium battery that exhibits an exceptionally high specific energy or high energy density; and provides a lithium metal-selenium or lithium ion-selenium cell with a cell specific energy greater than 300 Wh/kg, preferably greater than 400 Wh/kg (all based on the total cell weight). DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for an alkali metal-selenium battery containing an anode, a cathode, an electrolyte in ionic contact with the cathode and the anode, where the cathode comprises the graphene foam-protected selenium cathode layer.