Developing High-Capacity Rechargeable Batteries Based on Lithium-Sulfur Chemistry
The development of portable and transportation applications, such as the booming electrical vehicles, heavily relies on high-energy battery technologies. As the current Li-ion batteries approach the energy storage limit, the new battery chemistry that promises higher theoretical energy density should be pursued.1 Lithium-sulfur (Li-S) batteries use light-weight lithium as the anode and low-cost sulfur as the cathode and ether-based solution as the electrolyte. With the chemical conversion reaction of 16 Li + S8 ↔ 8 Li2S, Li-S batteries can provide a theoretical specific energy (2600 Wh/kg), 5 times over that of current Li-ion batteries.2, 3 Practical Li-S batteries require a low electrolyte amount and a limited amount of Li metal, otherwise, they cannot outperform the state-of-the-art Li-ion batteries in energy density.4, 5 But in most cases, both of these important parameters are compromised in order to achieve long cycle life. The project aims at understanding the electrochemical behavior of the batteries at the application-relevant conditions (low amount of electrolyte and Li metal) and then designing practical electrodes (S and Li) based on the acquired knowledge, and eventually building high capacity rechargeable batteries based on Li-S chemistry.