Microporous organic polymer-based lithium ion batteries with improved rate performance and energy density

Microporous organic polymers with triphenylamine segments were employed as cathode materials for lithium ion batteries. YPTPA with the highest surface area exhibits a discharge plateau at ∼3.6 V vs. Li/Li+, an initial Coulombic efficiency of 96.8% at 50 mA g−1 and a discharge capacity of 105.7 mAh g−1 at 200 mA g−1. Compared to the homo-coupled polymer of OPTPA with relatively low surface area (66 m2 g−1), SPTPA and YPTPA with higher surface area (544 and 1557 m2 g−1, respectively) show enhanced rate performances and energy densities. YPTPA can deliver 97.6 mAh g−1 within less than 3 min at high rate of 2000 mA g−1 and the energy density of 334 Wh kg−1 under an ultrahigh power density of 6816 W kg−1, while OPTPA only presents 48.2 mAh g−1 at 2000 mA g−1 with an energy density of 155 Wh kg−1 under 6414 W kg−1. The great improvement in electrochemical properties of SPTPA and YPTPA demonstrates that increasing surface area of polymer cathodes by interweaving the redox-active units into microporous polymer skeleton is an efficient way to develop advanced polymer cathode materials with outstanding electrochemical performance. [Display omitted] •Porous polymers were employed as cathode materials for lithium ion batteries.•The surface area of the polymer affects the electrochemical properties.•The polymers with high surface area exhibit improved electrochemical properties.•YPTPA can deliver 97.6 mAh g−1 within less than 3 min at 2000 mA g−1.