Bipolar conjugated microporous polymer with intrinsically fast reaction kinetics for high-energy-density and high-rate-capacity symmetric all-organic lithium-ion batteries

Abstract

The development of high-performance symmetric all-organic batteries (SAOBs) is of great significance for next-generation environmentally friendly energy storage systems with high energy and power densities. Herein, we report a bipolar conjugated microporous polymer (CMP), named PTTA, that is synthesized by integrating p-type tris(4-formylphenyl)amine and n-type 2,7-diaminopyrene-4,5,9,10-tetraone. It features a unique donor–acceptor (D–A) structure, hierarchical porosity, abundant redox-active sites, and chemical stability, which collectively endow PTTA with intrinsically fast electrochemical reaction kinetics. As a cathode, PTTA delivers a high specific capacity of 353 and 140 mA h g⁻¹ at 0.1 and 10.0 A g⁻¹, respectively, with 91% capacity retention after 2000 cycles at 5.0 A g⁻¹. As an anode, it achieves a high specific capacity of 1789 mA h g⁻¹ at 0.1 A g⁻¹. A PTTA-based SAOB (PTTA/PP/PTTA) in coin cells provides 257 mA h g⁻¹ at 1.0C and 148 mA h g⁻¹ at 67.9C. Moreover, a high-loading pouch-type device retains high electrochemical performance and reaches 277 Wh kg⁻¹. This demonstrates device-level feasibility and highlights the benefits of the D–A molecular design and hierarchical porosity in facilitating efficient bipolar redox reactions and fast charge storage. This work provides a valuable insight into the structure–function design principle of porous polymers for high-performance SAOB electrodes.