(1.School of Materials Science and Engineering, Shaanxi Normal University, Xi‘an 710062, China) (2.Beijing Institute of New Energy Technology, Beijing 102300, China)
Due to the high redox activity, low cost and diversity of the building blocks, organic redox active materials could be a class of promising electrode materials for rechargeable batteries. However, the high solubility of organic small molecules and linear polymers in organic electrolytes usually results in a rapid loss of capacity with cycling. Benefiting from the porous structure and highly conjugated polymer chains, conjugated microporous polymers have attracted great attention as electrode materials for rechargeable batteries. In this work, we employed biphenyl and anthraquinone as the building blocks to synthesize an anthraquinone-based conjugated polymer (PLPhAq) by palladium-catalyzed Suzuki coupling reaction. Owing to the high specific surface area of 257 m2·g-1 and plentiful active sites (—CO), the PLPhAq cathode for lithium-ion batteries shows a high specific capacity of 164 mAh·g-1 at the current density of 50 mA·g-1. After 800 cycles, PLPhAq still could maintain a reversible specific capacity of 126 mAh·g-1 at 50 mA·g-1. The PLPhAq cathode also exhibits a long and stable cycling stability with a slight capacity fading from 97 to 74 mAh·g-1 after 5000 cycles at a high current density of 1000 mA·g-1, demonstrating that conjugated microporous polymers could be a class of promising organic cathode materials for high performance lithiumion batteries.