Phase transformation induced benzene rings activation in a metal–organic framework to boost sodium storage performance

Metal-organic frameworks (MOFs) with permanent porosity and various crystal structures are promising materials for sodium-ion batteries (SIBs). The developing of new materials and the understanding of their sodium storage mechanisms and behaviours is critical to realize the practical application of MOFs in battery industry. In this communication, we report a unique sodium storage behaviour that more sodium ions can be inserted into the benzene rings of ligands and bond with sp2 carbon leading to superior sodium storage performance, which is realized via a benzene rings activation mechanism induced by thermally driven phase transformation. This work provides a new avenue for designing MOFs and other common types of carbonaceous materials to achieve superior sodium storage performance.