A lithium-sulfur cell consists of layers of the following:
• An anode of lithium metal, protected by a lithium sulfide passivation layer;
• A sulfur-based cathode – the sulfur combines with the lithium as the electrochemical reaction, but as sulfur has a low conductivity, carbon is also added. Polymer is then used to bind the cathode together; and
• Separator and Electrolyte. The choice of electrolyte is critical for ensuring the safety of the cell. For a safe cell, it is important to formulate an electrolyte which has high flash point and thus a low flammability.