Synergistic Effect of Hydrogen Bonding and π-π Stacking Enables Long Cycle Life in Organic Electrode Materials

Small-molecule organic compounds have emerged as attractive candidates for energy storage in lithium-ion batteries because of their sustainability and modularity. To develop generalizable design principles for organic electrode materials (OEMs), we investigated the correlation between electrochemical performance and addition of functional groups that promote synergistic hydrogen bonding and pi-pi stacking using a series of quinone-fused aza-phenazines (QAPs) with different hydrogen bonding donor/acceptor arrays. The QAP containing the most hydrogen bonding groups (3) exhibits the best performance with discharge capacities of 145 mAh g(-1) at 2C and with 82% capacity retention over 1000 cycles. The performance of 3 is attributed to the strategically incorporated hydrogen bonding groups, which facilitate strong intermolecular interactions and a tightly packed 2D structure. The intermolecular interaction strength was evaluated using variable temperature 1D H-1 NMR and 2D H-1-H-1 NOESY (nuclear Overhauser effect spectroscopy), offering a new strategy to help understand and predict the performance of OEMs with hydrogen bonding motifs.

Automated summary

Functional groups that promote hydrogen bonding and pi-pi stacking were added to improve the performance of organic electrode materials, with the QAP containing the most hydrogen bonding groups demonstrating superior performance due to strong intermolecular interactions and a tightly packed 2D structure. Evaluation of intermolecular interaction strength through NMR and NOESY spectroscopy offers a new strategy to understand and predict the performance of OEMs with hydrogen bonding motifs.