METHOD OF IMPROVING THE CHARGE/DISCHARGE CYCLE LIFE AND SAFETY OF AN ALKALI METAL-SULFUR SECONDARY BATTERY

Provided is a method of improving a cycle-life of a rechargeable alkali metal-sulfur cell, the method comprising implementing an electronically non-conducting anode-protecting layer between an anode active material layer and a cathode active material without using a porous separator in the cell, wherein the anode-protecting layer has a thickness from 1 nm to 100 μm and comprises an elastomer having a fully recoverable tensile elastic strain from 2% to 1,000%, a lithium ion or sodium ion conductivity from 10S/cm to 5×10S/cm, and an electronic conductivity less than 10S/cm when measured at room temperature. This battery exhibits an excellent combination of high sulfur content, high sulfur utilization efficiency, high energy density, no known dendrite issue, no dead lithium or dead sodium issue, and a long cycle life.