A Pyrazine-Based 2D Conductive Metal-Organic Framework for Efficient Lithium Storage

The merits of intrinsic electrical conductivity, high specific surface area, tunable chemical composition and tailor-made properties enable two-dimensional conductive metal-organic frameworks (2D c-MOFs) as promising next-generation electrode materials in the field of energy storage and conversion. Herein, we have designed and synthesized a novel pyrazine-based 2D c-MOF (TPQG-Cu-MOF) bearing extended p-conjugated structure and abundant redox active sites. Thanks to the excellent redox reversibility of pyrazine units and CuO2 units, as well as the insolubility of the rigid framework skeleton, TPQG-Cu-MOF as the cathode material of lithium-ion battery exhibits a reversible specific capacity (150.2 mAh center dot g(-1) at 20 mAh center dot g(-1)), good cycling stability (capacity retention of 82.6% after 500 cycles at 1 A center dot g(-1)) and excellent rate performance. Comprehensive ex-situ spectroscopic studies revealed the reversible redox activity of pyrazine units and CuO2 units of TPQG-Cu-MOF during the Li+ insertion/extraction process. The deepening fundamental understanding of the structure-property relationship was proposed, which might pave the way for further development of efficient MOF-based energy storage devices.