Conjugated Polymers with Benzoyl-N-methylpyridinium Units: An Effective Design Strategy for High-Performance Lithium-Ion Batteries

The development of new redox-active conjugated polymers with superior electrochemical performance is a highly rewarding direction for a range of sustainable energy-storage applications that are needed to address climate change. In this work, we report a new class of conjugated polymers P1–P3 with pendant benzoyl-N-methylpyridinium (BMP) units for lithium-ion batteries with desirable high performance and stability. Our design strategy places the redox activity on spatially separated benzoyl pyridinium groups so that the redox centers can operate relatively interference-free, while at the same time, providing an efficient electron-conduction pathway along the conjugated polymer backbone. At a current density of 0.2 A g–1, batteries that employ the new functional polymers as electrodes exhibited superior capacities up to 320 mAh g–1. Even at a relatively high current of 1 A g–1, high specific capacities of up to 236 mAh g–1 can still be reached after 500 cycles. Notably, the capacities only drop by 5–10% after 1000 cycles, all the while maintaining a Coulombic efficiency of 99%. This work highlights the impressive potential of redox-active BMP units for the construction of high-performance active battery materials.