Design of multishell microsphere of transition metal oxides/carbon composites for lithium ion battery

Although the synthesis of transition metal oxide hollow structure is well established, it is still very difficult to control the size distribution, morphological uniformity, cavity volume, shell clarity and functional groups of products. Herein, the strategy of "oxidation-sedimentation-recrystallization-formation" was proposed to synthesis of well-defined multi-shelled hollow microsphere by thermal oxidation of the metal-organic frameworks (MOFs) general precursors. The spherical Ni-MOF and Co-MOF are first synthesized and subsequently transformed into corresponding multi-shelled metal oxide and carbon composites. These nitrogen-doped multi-shelled Co3O4@ carbon hollow microspheres were adopted as anode for lithium-ion batteries, demonstrating remarkable electrochemical properties. Impressively, an ultra-high reversible capacity of 1701 mAh g(-1) was retained at a current density of 100 mA g(-1) after 60 cycles. Even at a large current density of 5000 mA g(-1), 427 mAh g(-1) was retained.