Donor–Acceptor Conjugated Microporous Polymer toward Enhanced Redox Kinetics in Lithium–Sulfur Batteries
Tianxiang Huang, Gengyuan Zhang, Ruwei Chen, Shangjun Lin, Hujing Zhou, Jiangtao Li, Lai‐Hon Chung, Xuanhe Hu, Lin Yu, Jun He
Abstract
Conjugated microporous polymers (CMPs) with porous structure and rich polar units are favorable for high-performance lithium–sulfur (Li–S) batteries. However, understanding the role of building blocks in polysulfide catalytic conversion is still limited. In this work, two triazine-based CMPs are constructed by electron-accepting triazine with electron-donating triphenylbenzene (CMP-B) or electron-accepting triphenyltriazine (CMP-T), which can grow on a conductive carbon nanotube (CNT) to serve as separator modifiers for Li–S batteries. CMP-B@CNT features faster ion transportation than the counterpart of CMP-T@CNT. More importantly, compared with acceptor–acceptor (A–A) CMP-T, donor–acceptor (D–A) CMP-B possesses a higher degree of conjugation and a narrower band gap, which are conducive to the electron transfer along the polymer skeleton, thus accelerating the sulfur redox kinetics. Consequently, the CMP-B@CNT functional separator endows Li–S cells with an outstanding initial capacity of 1371 mAh g –1 at 0.1 C and favorable cycling stability with a capacity degradation rate of 0.048% per cycle at 1 C for 800 cycles. This work provides insight into the rational design of efficient catalysts for advanced Li–S batteries.