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

• 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.

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.

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