Xiaowei Wang1,Bhargav Bhamwala1,Saurabh Parab1,Bingyu Lu1,Darren Tan1,Y. Shirley Meng2,1
University of California San Diego1,The University of Chicago2
Xiaowei Wang1,Bhargav Bhamwala1,Saurabh Parab1,Bingyu Lu1,Darren Tan1,Y. Shirley Meng2,1
University of California San Diego1,The University of Chicago2
Commercialization of high energy lithium-sulfur battery is hampered by bottlenecks like low sulfur loading, high cathode porosity, low cycling stability. Herein, we developed a tool box of quantification to identify the limiting factors in Li-S batteries under practical lean Li and electrolyte conditions. As guided by the root reasons identified, we strategically synthesized densely stacked redox-active hexaazatrinaphthylene (HATN) polymer with a surface area of 302 m<sup>2</sup> g<sup>-1</sup> and a very high bulk density of ~1.6 g cm<sup>-3</sup>. Uniquely, HATN polymer has a similar redox potential window to S, which facilitates the binding of Li<sub>2</sub>S<sub><i>x</i></sub> and its transformation chemistry within the bulky polymer host, leading to fast Li<sub>2</sub>S/S kinetics. For another, we designed and synthesized a non-sacrificial NewEle to replace the decomposition-based LiNO<sub>3</sub> to achieve long cycle lifespan of Li-S battery. The compact polymer/S electrode presents a high sulfur loading of ~10 mg<sub>s</sub> cm<sup>-2</sup> with a low cathode porosity of 30%. It delivers a high areal capacity of ~10 mAh cm<sup>-2</sup> and good cycling stability (500+ cycles) at electrolyte-sulfur (E/S) ratio of 5 μl mg<sub>s</sub><sup>-1</sup>. This works paves the way for achieving practical high energy Li-S battery with long lifespan.