Surface-stabilized selenium particles, alkali metal-selenium secondary battery containing same, and method of manufacturing

A method of manufacturing a lithium-selenium, sodium-selenium or potassium-selenium battery, said method comprising:

• (a) providing a cathode active material layer and an optional cathode current collector to support said cathode active material layer;
• (b) providing an anode active material layer and an optional anode current collector to support said anode active material layer;
• and
• (c) providing an electrolyte in contact with the anode active material layer and the cathode active material layer and an optional separator electrically separating the anode and the cathode;
• wherein the operation of providing the cathode active material layer includes providing multiple particulates of a cathode active material, wherein at least one of said particulates comprises one or a plurality of cathode active material particles being fully embraced or encapsulated by a thin layer of a protecting polymer wherein said cathode active material particles are selected from Se, lithium polyselenide, sodium polyselenide, potassium polyselenide, a Se alloy or mixture with Sn, Sb, Bi, S, or Te, or a combination thereof and said protecting polymer layer, having a lithium ion conductivity from 10−8 S/cm to 5×10−2 S/cm at room temperature and a thickness from 0.5 nm to 10 μm, contains a polymer selected from the group consisting of poly(ethylene oxide) (PEO), polypropylene oxide (PPO), poly(acrylonitrile) (PAN), poly(methyl methacrylate) (PMMA), poly(vinylidene fluoride) (PVdF), poly bis-methoxy ethoxyethoxide-phosphazene, polyvinyl chloride, poly(vinylidene chloride), polydimethylsiloxane, poly(vinylidene fluoride)-hexafluoropropylene (PVDF-HFP), polyethylene glycol (PEG), chemical derivatives of PEG, poly(ethylene glycol diacrylate) (PEGDA), polyethylene glycol methyl ether, polyethylene glycol dimethyl ether, sulfonated polymers, interpenetrating polymer networks thereof, and combinations thereof.