A tricycloquinazoline based 2D conjugated metal-organic framework for robust sodium-ion batteries with co-storage of both cations and anions.

There is growing interest in 2D conjugated metal-organic frameworks (2D -MOFs) for batteries due to their reversible redox chemistry. Nevertheless, currently reported 2D -MOFs based on n-type ligands are mostly focused on the storage of cations for batteries. Herein, we successfully synthesize nitrogen-rich and electron-deficient p-type ligand-based Ni(HATQ) assembled from 2,3,7,8,12,13-hexaaminotricycloquinazoline (HATQ), and the ion co-storage feature of cations and anions in sodium ion batteries (SIBs) is demonstrated for 2D -MOFs for the first time. The redox chemistry from the p-type ligand and π-d hybridization center endows the Ni(HATQ) cathode with high capacity and good rate performance, especially excellent capacity retention of 95% after 1000 cycles. These findings provide a promising avenue for the exploration of other p-type multidentate chelating ligands toward new 2D -MOFs and expand the application of 2D -MOFs in energy storage systems.