Hollow tubular conjugated organic polymer for lithium batteries

Polymerization is a valid strategy to solve the dissolution issue of organic electrode materials in aprotic electrolytes. However, conventional polymers usually with amorphous structures and morphology’s influence on electrochemistry have rarely been studied. Herein, a hollow tubular poly phenyl pyrene-4,5,9,10-tetraone (T-PPh-PTO) organic cathode material was designed and synthesized based on the concentration-gradient of the precursor (PTO-Br₂) and asymmetrical internal diffusion during the reaction. The unique hollow structure endowed T-PPh-PTO with a short Li⁺ diffusion path accompanied by a high diffusion coefficient (D ${}_{{\mathrm{L}\mathrm{i}}^{+}}$ ≈ 10⁻⁸ cm²·s⁻¹). Thus, T-PPh-PTO presented a capacitance-dominated redox pseudocapacitance action with an outstanding rate performance (173 mAh·g⁻¹ at 2 A·g⁻¹) and high cycle stability (capacity retention ratio is 91.7% after 2,000 cycles). Our study leads to further developments in designing unique organic structures for energy storage.