Process for Alkali Metal-Selenium Secondary Battery Containing a Cathode of Encapsulated Selenium Particles

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 10S/cm, and a thickness from 0.5 nm to 10 μm.