Performance of Lithium Sulfur Batteries Consisting of Li_2s/Carbon Composite Cathode

摘要

Lithium sulfur (Li-S) battery is a rechargeable battery typically consisting of sulfur as a cathode, Li metal as an anode, and a Li-ion conductive electrolyte. The sulfur has many advantages, such as high gravimetric theoretical capacity, high terrestrial abundance, and low price. Despite this potential, Li-S batteries are facing some challenges. Firstly, sulfur is an electrical insulator, which requires a large amount of conductive additive such as carbon for the formation of the electron conduction path. As a result, the loading amount of sulfur on the cathode is hard to increase. Secondly, lithium polysulfide intermediates dissolve in conventional organic electrolytes, leading to a redox shuttle. Thirdly, the volume expansion/shrinkage of sulfur during lithiation/delithiation is large, resulting in the mechanical degradation of the electron-conduction path in the electrode, which deteriorates the capacity. Finally, Li dendrites grow on Li metal during cycles, which causes a short circuit.