Microwave-assisted synthesis of platelet-like cobalt metal-organic framework, its transformation to porous layered cobalt-carbon nanocomposite discs and their utilization as anode materials in sodium-ion batteries

In this work a facile microwave-assisted synthesis of a platelet-like cobalt-based metal-organic framework (MOF) material is presented. This material was synthesized from cobalt(II) acetylacetonate and biphenyl-4,4'-dicarboxylic acid (Bpdc) in N,N'-dimethylformamide at 160 degrees C. As-prepared Co-Bpdc MOF product with a platelet-like disc architecture was transformed by heat treatment in a nitrogen atmosphere at 800 degrees C to porous cobalt-carbon nanocomposite discs. It is demonstrated that this synthetic strategy allows for obtaining magnetic microporous carbon layered discs with homogeneously incorporated metallic cobalt nanoparticles with a size of ca. 4 nm. The Co-C nanocomposite material was characterized by a variety of physico-chemical methods. It is shown that both Co-Bpdc MOF and Co-C nanocomposite were electrochemically active in sodium battery system as a material for the negative electrode. The high capacity retention over 80% and capacities over 200 mAh g(-1) in the sodium-ion battery systems have been achieved.