Provided is a pre-selenized cathode for an alkali metal-selenium cell, comprising (A) an integral layer of a mesoporous structure of a carbon, graphite, metal, or conductive polymer, wherein the mesoporous structure has mesoscaled pores with a pore size of 0.5-50 nm and a specific surface area from 100 to 3,200 m.sup.2/g and (b) nanoparticles or nanocoating of selenium or metal selenide having a diameter or thickness from 0.5 nm to 20 nm, wherein selenium or metal selenide resides in the mesoscaled pores and occupies an amount from 50% to 99% by weight based on the total weight of selenium or metal selenide and the integral layer of mesoporous structure combined.

Provided is a rechargeable alkali metal-selenium cell comprising an anode active material layer, an electrolyte, and a cathode active material layer containing multiple particulates of a selenium-containing material selected from a selenium-carbon hybrid, selenium-graphite hybrid, selenium-graphene hybrid, conducting polymer-selenium hybrid, a metal selenide, a Se alloy or mixture with Sn, Sb, Bi, S, or Te, a selenium compound, or a combination thereof and wherein at least one of the particulates comprises one or a plurality of selenium-containing material particles being embraced or encapsulated by a thin layer of an elastomer having a recoverable tensile strain no less than 5% when measured without an additive or reinforcement, a lithium ion conductivity no less than 10.sup.7 S/cm at room temperature, and a thickness from 0.5 nm to 10 m This battery exhibits an excellent combination of high selenium content, high selenium utilization efficiency, high energy density, and long cycle life.

Provided is particulate for use in a lithium-selenium battery cathode, the particulate comprising one or a plurality of cathode active material particles (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) being embraced or encapsulated by a thin layer of a protecting polymer having a lithium ion conductivity from 10.sup.8 S/cm to 510.sup.2 S/cm and a thickness from 0.5 nm to 10 m, wherein the protecting polymer layer contains a polymer selected from 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 (PEG-me), polyethylene glycol dimethyl ether (PEG-de), sulfonated polymers, interpenetrating polymer networks thereof, and combinations thereof.

Provided is a method of manufacturing an alkali metal-selenium cell, comprising: (a) providing a cathode; (b) providing an alkali metal anode; and (c) combining the anode and the cathode and adding an electrolyte in ionic contact with the anode and the cathode to form the cell; wherein the cathode contains multiple particulates of a selenium-containing material selected from selenium, a selenium-carbon hybrid, selenium-graphite hybrid, selenium-graphene hybrid, conducting polymer-selenium hybrid, a metal selenide, a Se alloy or mixture with Sn, Sb, Bi, S, or Te, a selenium compound, or a combination thereof and wherein at least one of the particulates comprises one or a plurality of selenium-containing material particles being embraced or encapsulated by a thin layer of an elastomer having a recoverable tensile strain from 5% to 1000%, a lithium ion conductivity no less than 10.sup.7 S/cm, and a thickness from 0.5 nm to 10 m.

Provided is a rechargeable alkali metal-selenium cell comprising an anode active material layer, an electrolyte, and a cathode active material layer containing multiple particulates of a selenium-containing material selected from a selenium-carbon hybrid, selenium-graphite hybrid, selenium-graphene hybrid, conducting polymer-selenium hybrid, a metal selenide, a Se alloy or mixture with Sn, Sb, Bi, S, or Te, a selenium compound, or a combination thereof and wherein at least one of the particulates comprises one or a plurality of selenium-containing material particles being embraced or encapsulated by a thin layer of a high-elasticity polymer having a recoverable tensile strain no less than 5% when measured without an additive or reinforcement, a lithium ion conductivity no less than 10.sup.7 S/cm at room temperature, and a thickness from 0.5 nm to 10 m This battery exhibits an excellent combination of high selenium content, high selenium utilization efficiency, high energy density, and long cycle life.

Provided is a method of manufacturing a rechargeable alkali metal-selenium cell, comprising: (a) providing a cathode and an optional cathode current collector to support the cathode; (b) providing an alkali metal anode and an optional anode current collector to support said anode; and (c) providing an electrolyte in contact with the anode and the cathode and an optional separator electrically separating the anode and the cathode; wherein the cathode contains multiple particulates of a selenium-containing material wherein at least one of the particulates comprises one or a plurality of selenium-containing material particles being embraced or encapsulated by a thin layer of a high-elasticity polymer having a recoverable tensile strain from 5% to 1,000% when measured without an additive or reinforcement, a lithium ion conductivity no less than 10.sup.7 S/cm at room temperature, and a thickness from 0.5 nm to 10 m.

The present invention discloses a preparation method to make lithium selenium secondary battery cathode materials with a high energy density and stable electrochemical performances. Two dimensional carbon materials prepared from the presently-disclosed method is not only made from readily-available low-cost raw materials, but is also of simple preparation method. It can effectively shorten the migration distance of lithium ions in the charging and discharging process and improve conductivity and utilization of selenium after compounded with carbon and selenium; the selenium carbon cathode material can be assembled into lithium selenium secondary batteries with high energy density and stable electrochemical performances. By further scaling up, the assembled lithium selenium pouch-cell batteries still hold excellent electrochemical performances and high energy density, showing broad application prospects.

Provided is a lithium battery anode electrode comprising multiple particulates of an anode active material, wherein at least a particulate is composed of one or a plurality of particles of an anode active material being encapsulated by a thin layer of inorganic filler-reinforced elastomer having from 0.01% to 50% by weight of an inorganic filler dispersed in an elastomeric matrix material based on the total weight of the inorganic filler-reinforced elastomer, wherein the encapsulating thin layer of inorganic filler-reinforced elastomer has a thickness from 1 nm to 10 m, a fully recoverable tensile strain from 2% to 500%, and a lithium ion conductivity from 10.sup.7 S/cm to 510.sup.2 S/cm and the inorganic filler has a lithium intercalation potential from 1.1 V to 4.5 V (preferably 1.2-2.5 V) versus Li/Li.sup.+. The anode active material is preferably selected from Si, Ge, Sn, SnO.sub.2, SiO.sub.x, Co.sub.3O.sub.4, Mn.sub.3O.sub.4, etc.

A process for producing a lithium battery, comprising: (A) Assembling a porous cell framework composed of a foamed anode current collector, a foamed cathode current collector, and a porous separator disposed between the two collectors; wherein the current collector(s) has a thickness no less than 100 m and at least 80% by volume of pores; (B) Preparing a first suspension of an anode active material dispersed in a first liquid electrolyte and a second suspension of a cathode active material dispersed in a second liquid electrolyte; and (C) Injecting the first suspension into pores of the anode current collector to form an anode and injecting the second suspension into pores of the cathode current collector to form a cathode to an extent that the anode active material and the cathode active material combined constitutes an electrode active material mass loading no less than 40% of the total battery cell weight.

An electrochemical device including: an anode, a cathode, an electrolyte, and a separator separating the anode from the cathode. The separator includes a material that includes at least one of: a linear polymer; a kinetic friction coefficient of up to 2.0; an elongation of at least 240, elongation defined as elongation at break; a ratio of elongation to thickness of at least 10; and/or a modulus of elasticity of up to 270 MPa.