Two isomorphous coordination polymer-derived metal oxides as high-performance anodes for lithium-ion batteries

Two isomorphous 2D coordination polymers (CPs), [Co(L)₂]_n(1) and [Ni(L)₂]_n(2) (HL = 4-benzimidazole-1-yl-benzoic acid), have been synthesized under solvothermal conditions as precursors for metal oxides and characterized by single-crystal X-ray diffraction, revealing that both compounds 1 and 2 present porous 4⁴ topology. The CP-derived metal oxides Co₃O₄ and NiO were prepared and examined as anodes for lithium-ion batteries in the potential range of 0.01-3.0 V. Both exhibit excellent cycle stability and high Coulombic efficiency at high current density, and the Co₃O₄ electrode presents superior electrochemical performance. Co₃O₄ can achieve a specific capacity of 569.8 mA h g^-1 with 98% Coulombic efficiency after 50 cycles at a high current density of 2000 mA g^-1.