Dense‐Stacking Porous Conjugated Polymer as Reactive‐Type Host for High‐Performance Lithium Sulfur Batteries
Xiaowei Wang, Yangyuchen Yang, Chen Lai, Runlai Li, Haomin Xu, Darren H. S. Tan, Kun Zhang, Wei Yu, Øeystein Fjeldberg, Ming Lin, Wei Tang, Ying Shirley Meng, Kian Ping Loh
Abstract
Abstract Commercialization of the lithium‐sulfur battery is hampered by bottlenecks like low sulfur loading, high cathode porosity, uncontrollable Li 2 S x deposition and sluggish kinetics of Li 2 S activation. Herein, we developed a densely stacked redox‐active hexaazatrinaphthylene (HATN) polymer with a surface area of 302 m 2 g −1 and a very high bulk density of ca. 1.60 g cm −3 . Uniquely, HATN polymer has a similar redox potential window to S, which facilitates the binding of Li 2 S x and its transformation chemistry within the bulky polymer host, leading to fast Li 2 S/S kinetics. The compact polymer/S electrode presents a high sulfur loading of ca. 15 mg s cm −2 (200‐μm thickness) with a low cathode porosity of 41 %. It delivers a high areal capacity of ca. 14 mAh cm −2 and good cycling stability (200 cycles) at electrolyte–sulfur (E/S) ratio of 5 μL mg s −1 . The assembled pouch cell delivers a cell‐level high energy density of 303 Wh kg −1 and 392 Wh L −1 .