An Ultra‐Stable 2D Linear Polymer Cathode for High‐Performance Aqueous Zinc‐Organic Batteries

Two‐dimensional structure of cathode materials possesses fast kinetics in aqueous zinc ion batteries. However, in organic linear polymers it is rare to form two‐dimensional structures due to the bond rotations of the polymerization reaction. In this work, inspired by the process of forming carbon fibers from polyacrylonitrile, a novel two‐dimensional linear polymer (2DLP) of poly(2H,11H‐bis[l,4]triazino[3,2‐b:3',2'‐m]triphenodithiazine‐3,12‐diyl‐2,11‐diyli‐dene‐11,12‐bis[methyldene]) (PTL) cathode materials were prepared for aqueous zinc‐ion battery cathode materials by designing ladder structure polymer molecules with highly restricted bond rotations. PTL possess fast cations diffusion (4.27×10‐7 cm‐1 s‐1) due to its layered structure. Moreover, the PTL electrodes exhibit an ultra‐long cycle stability (7000 cycles still remain 87% capacity remains). Meanwhile, as PTL mass loading increase from 3.13 to 6.27 mg cm‐2, the specific capacity kept 98% retention after 100 cycles. Besides, the assembled Zn/PTL flexible pack battery exhibits a 6.6 mAh capacity at 0.5 A g‐1. Furthermore, though a range of ex site analysis, it was supported that the charge storage mechanism of PTL is driven by the imine moiety, and accompanies by the insertion and extraction of Zn2+/H+ ions. This work attempts to provide a new sight of improve the poor ion diffusion coefficient of organic materials.