Preparation And Properties Of MOFs-derived Co₃O₄/C Anode Materials For Lithium-ion Battery

As an efficient energy storage system lithium-ion batteries have received much attention.Under the current situation that the overall performance of lithium battery anode materials is limited,organometallic framework materials（MOFs）derivatives with novel porous structures are used as lithium battery anode materials,which exhibit excellent lithium storage performance.Co-MOF and ZIF-67 precursors were prepared by solvothermal and room temperature co-precipitation method,respectively.The effects of raw material ratio,heat treatment method and temperature on the two MOFs-derived composites were investigated respectively.Among them,graphene oxide（GO）and multi-walled carbon nanotubes（MWCNTs）are composited in the Co-MOF precursor to improve the performance of derivatives,and ZIF-67 is used to derive bimetal oxide composites by introducing zinc source compounds.The structure and electrochemical properties of the above electrode materials were characterized by XRD,SEM,BET,cyclic voltammetry,and constant current charge-discharge tests.When the molar ratio of Co（NO₃）₂·6H₂O and H₃BTC is 1:1 to get Co-MOF then calcined at 600℃to obtain Co₃O₄/C that has excellent rate performance due to the large specific surface area(34.8 m²·g^-1).At a current density of 100 m A·g^-1 Co₃O₄/C@MWCNTs retains a discharge specific capacity of 710 m Ah·g^-1 after 100 cycles when the MWCNTs composite mass fraction is 10 wt%.When the a molar ratio of Co（NO₃）₂·6H₂O and C₄H₆N₂ is 1:4 to get ZIF-67 then calcined at 700℃to obtain Co₃O₄/Co O/C that has the best performance.Benefiting from the more mesoporous structure and large specific surface area(130.5 m²·g^-1),the capacity can retain 528.8 m Ah·g^-1 after 100 cycles at a current density of 100 m A·g^-1.Co₃O₄/Zn O/C derived from Zn/Co-ZIFs generates a large number of CNTs in situ.Benefiting from the large specific surface area(249.5 m²·g^-1),good electrical conductivity,unique mechanical stability and bimetallic synergy caused by the abundant CNTs,its discharge specific capacity tends to be 995.5 m Ah·g^-1 after 500 cycles at a current density of 500 m A·g^-1.Figure 77;Table 11;Reference 78.