Understanding of Electrochemical Oxidation Route of Electrically Isolated Li2S Particles

New insight into the oxidation mechanism of solid Li 2 S is presented by investigating a specially designed cell in which the Li 2 S particles are electrically isolated from the carbon cathode. Surprisingly, the cell containing the isolated Li 2 S particles delivered considerable charge and discharge capacities despite the prevention of any charge transfer process between the Li 2 S particles and the carbon cathode. This fact directly indicates that the electrochemical oxidation of Li 2 S occurs not through a direct charge (electron) transfer between solid Li 2 S and conducting materials but through chemical reactions coupled with the charge transfer process. We believe that these unexpected results will greatly contribute to a deep understanding of the exact working mechanism of Li-S batteries and Li 2 S cathodes as well as a paradigm shift toward an innovative and rational design of Li-S batteries.