New Hybrid Nano-Architecture of Sulfur Electrode for Lithium-Sulfur Batteries.

Lithium-Sulfur batteries have the potential to provide a much greater energy storage capacity than current Lithium-ion batteries. However, Lithium-Sulfur batteries are hampered by challenges arising from the cell level, such as poor conductivity of sulfur, its volume expansion, and the lithium polysulfides shuttle effect. The technology developed in our lab overcomes these fundamental challenges by implementing an innovative electrode architecture that exploits the properties of vertically aligned carbon nanotubes (VACNTs). The hierarchical-assembled-nanostructured battery positive electrode is based on carbon nanotube carpets grafted by 100% sulfur nanomaterial. Coupling it with metallic lithium as negative electrode results in high energy and power, and long-life Lithium-Sulfur battery (Figure 1). The positive electrode topology enables to store more electrical charge more rapidly than any other commercial electrode, positively impacting the power and energy storage capacity of the battery. The Lithium-Sulfur batteries exclude inactive components (such as binders/additives essential for traditional Lithium-ion batteries), thus eliminating the “dead weight” found in the today’s batteries.<br/>Electrochemical performance tests have shown that the Lithium-Sulfur batteries developed in our work have substantially improved capacity performance, stability and cycle life compared to conventional Lithium-Sulfur batteries. At a discharging rate of 2C (i.e., 30 minutes), the cells have shown a stable specific capacity of 400 mAh g^-1over 1000 cycles.