Integrated High Voltage, Large Capacity, and Long‐Time Cyclic Stability of Lithium Organic Battery Based on a Bipolar‐Type Cathode of Triphenylamine‐Hydrazone COF Material

Abstract

Covalent organic frameworks (COFs) are a promising class of electrode materials for lithium‐ion batteries. However, the reported cathodes of COFs typically exhibit low potential and voltage plateaus, which limits their further applications. In this work, a new hydrazone three‐dimensional (3D) COF material with bipolar characteristics, PTB‐DHZ‐COF, is constructed by Schiff base condensation of monomeric PTB with DHZ. The cell with PTB‐DHZ‐COF as the cathode exhibits a wide potential range of 1.2–4.2 V and a discharge voltage plateau of over 3.6 V. PTB‐DHZ‐COFX composites are successfully prepared by compounding PTB‐DHZ‐COF with carbon nanotubes. PTB‐DHZ‐COF40 cells show high specific capacity (114.24 mAh·g−1 at 1000 mA·g−1), excellent cycling capability (86.3% capacity retention after 5000 cycles), and ultra‐high energy density (489 Wh·kg−1 at 50 mA·g−1). This work provides a new strategy for the design of new COF materials and the development of high‐performance organic energy storage electrodes.