▎ 摘　　要

NOVELTY - An alkali metal-selenium battery comprises an anode comprising an active material layer and an optional current collector, a cathode comprising an active material layer and an optional current collector, an electrolyte, and an optional porous separator that electronically insulates and separates the anode and the cathode, and a graphene separator layer comprising a solid graphene foam, paper or fabric that is permeable to lithium ions or sodium ions, and non-permeable to selenium or metal selenide ions. The graphene separator layer comprises pristine graphene sheets or non-pristine graphene sheets. The non-pristine graphene is chosen from graphene oxide, reduced graphene oxide, graphene fluoride, graphene chloride, graphene bromide, nitrogenated graphene, boron-doped graphene, nitrogen-doped graphene, and chemically functionalized graphene. The cathode active material is chosen from selenium, selenium-carbon hybrid, selenium-graphite hybrid, selenium-graphene hybrid and metal selenide. USE - Alkali metal-selenium battery e.g. rechargeable lithium-selenium cell, sodium-selenium cell, potassium-selenium cell, lithium ion-selenium cell, sodium ion-selenium cell and potassium ion-selenium cell (all claimed). Uses include but are not limited to electric vehicle, hybrid vehicle, laptop and mobile phone. ADVANTAGE - The alkali metal-selenium battery has high energy density and capacity even after repeated charging and discharging, reduced internal resistance and suppressed corrosion of current collectors and electrical leads. DETAILED DESCRIPTION - An alkali metal-selenium battery comprises an anode comprising an active material layer and an optional current collector supporting the active material layer, a cathode comprising an active material layer and an optional current collector supporting the active material layer, an electrolyte in ionic contact with the cathode and the anode, and an optional porous separator that electronically insulates and separates the anode and the cathode, and a graphene separator layer comprising a solid graphene foam, paper or fabric that is permeable to lithium ions or sodium ions, and non-permeable to selenium or metal selenide ions. The graphene separator layer is provided between the anode active material layer and the cathode active material layer, and is in physical contact with the cathode active material layer, but not in physical contact with the anode active material layer. The graphene separator layer comprises pristine graphene sheets having less than 0.01 wt.% non-carbon elements, or non-pristine graphene sheets having 0.01-20% non-carbon elements. The non-pristine graphene is chosen from graphene oxide, reduced graphene oxide, graphene fluoride, graphene chloride, graphene bromide, nitrogenated graphene, boron-doped graphene, nitrogen-doped graphene, and chemically functionalized graphene. The cathode active material is chosen from selenium, selenium-carbon hybrid, selenium-graphite hybrid, selenium-graphene hybrid, conductive polymer-selenium hybrid, metal selenide and selenium alloy, and tin, antimony, bismuth, sulfur or tellurium.