Facile construction of two-dimensional coordination polymers with a well-designed redox-active organic linker for improved lithium ion battery performance

A well-designed redox-active organic linker, pyrazine-2,3,5,6-tetracarboxylate (H4pztc) with brimming active sites for lithium ions storage was utilized to construct coordination polymers (CPs) via a facile hydrothermal reaction. Those two isostructural two-dimensional (2D) CPs, namely [M2(pztc)(H2O)6]n (M=Co for 1 and Ni for 2), delivered excellent reversible capacities and stable cycling performance as anodes in lithium ion batteries. As demonstrated in electrochemical studies, 1 and 2 can achieve highly reversible capacities of 815 and 536 mA h g−1 at 200 mA g−1 for 150 cycles, respectively, best performed for the reported 2D-CP-based anode materials. The electrochemical mechanism studies showed that the remarkable performances can be ascribed to the synergistic Li-storage redox reactions of metal centers and organic moieties. Our work highlights the opportunities of using a well-designed organic ligand to construct low-dimensional CPs as new type of electrode materials for advanced lithium ion batteries.