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
Weijun Li, Qidi Huang, Hongliang Shi, Wei Gong, Liang Zeng, Haiyang Wang, Yu Kuai, Zhangxin Chen, Haichang Fu, Yujie Dong, Cheng Zhang
Abstract
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.