Porous Organic Polymers with Multiple p-Type Redox-Active Sites as Organic Cathode Materials for Lithium-Ion Batteries with >3.5 V Output Voltage

Abstract

Porous organic polymers (POPs) have shown great potential as organic cathode materials (OCMs) for advanced lithium-ion batteries (LIBs). However, OCMs still face challenges such as insufficient output voltages. In this work, we report the design and synthesis of two dihydrophenazine-based POPs (denoted as TPBPA-DHP and PPT-DHP) with multiple p-type redox-active sites. When employed as OCMs for LIBs, both TPBPA-DHP and PPT-DHP cathodes exhibit high voltage platform characteristics, achieving ultrahigh output voltages of 3.59 and 3.61 V, respectively, along with remarkable energy densities of 536.8 and 502.1 Wh·kg^–1. Benefiting from their highly crosslinked structures and robust skeletons, both POP cathodes exhibit long cycle stability, retaining 72.7% and 70.8% of their capacities after 1000 cycles at 0.5 A·g^–1. Ex situ FT-IR spectra and EPR measurements were conducted to elucidate the redox mechanism involving anion interactions with p-type redox-active centers. Moreover, the PPT-DHP//graphite full cell delivers a high average discharge capacity of 129.2 mAh·g^–1 at 0.1 A·g^–1, retaining 76.9% of its initial capacity after 1000 cycles at 0.5 A·g^–1. This study provides valuable insights into the molecular design and synthesis of p-type POPs for the next generation high-voltage LIBs.

Keywords

Porous polymers / p-Type / Organic cathodes / Lithium-ion batteries / High voltage / High energy density / Electrochemistry

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2025 SIOC, CAS, Shanghai, & WILEY-VCH GmbH.