Conjugation and Topology Engineering of 2D π-d Conjugated Metal-Organic Frameworks for Robust Potassium Organic Batteries.

The evolution of two-dimensional conjugated metal-organic frameworks (2D c-MOFs) provides a significant prospect for researching the next generation of green and advanced energy storage systems (ESSs). Especially, conjugation and topology engineering serve as an irreplaceable character in adjusting the electrochemical properties of ESSs. Herein, we proposed a novel strategy using conjugation and topology engineering to demonstrate the application of 2D c-MOFs in robust potassium-ion batteries (PIBs) for the first time. By comparing 2D c-MOFs with the rhombus/kagome structure as well as three/four-arm core, the rhombus structure (sql-Cu-TBA-MOF) cathode for PIBs can display the impressive electrochemical performance, including a high specific discharge capacity of 178.4 mAh g (at 0.2 A g) and a well long-term cycle stability of more than 9,000 (at 10.0 A g). Moreover, full PIBs (FPIBs) are constructed by pairing sql-Cu-TBA-MOF cathode with dipotassium terephthalate (KTP) anode, which delivers a high reversible discharge specific capacity of 146.6 mAh g (at 0.1 A g) and great practical application prospect. These findings provide reasonable implications for the design of 2D c-MOFs from the perspective of conjugation and topology engineering for advanced energy storage systems.