Hydrogen Bond Networks Stabilized High-Capacity Organic Cathode for Lithium-Ion Batteries

High-capacity small organic materials are plagued by their high solubility. Here we proposed constructing hydrogen bond networks (HBN) via intermolecular hydrogen bonds to suppress the solubility of active material. The illustrated 2, 7- diamino-4, 5, 9, 10-tetraone (PTO-NH2) molecule with intermolecular hydrogen (H) bond between O in -C=O and H in -NH2, which make PTO-NH2 presents transverse two-dimensional extension and longitudinal pi-pi stacking structure. In situ Fourier transform infrared spectroscopy (FTIR) has tracked the reversible evolution of H-bonds, further confirming the existence of HBN structure can stabilize the intermediate 2-electron reaction state. Therefore, PTO-NH2 with HBN structure has higher active site utilization (95 %), better cycle stability and rate performance. This study uncovers the H-bond effect and evolution during the electrochemical process and provides a strategy for materials design.

Automated summary

In this study, a hydrogen bond network (HBN) was proposed to suppress the solubility of high-capacity small organic materials. The H-bond formation between H and O in PTO-NH2 molecule resulted in a transverse two-dimensional extension and longitudinal pi-pi stacking structure. The HBN structure enhanced active site utilization, cycle stability, and rate performance of PTO-NH2.