Ionic liquid derived Co3O4/Nitrogen doped carbon composite as anode of lithium ion batteries with enhanced rate performance and cycle stability

Co 3 O 4 /Nitrogen doped carbon (Co 3 O 4 /NDC) composite is successfully prepared using 1-butyl-3-methylimidazolium dicyanamide ([BMIm]N(CN) 2 ) as carbon and nitrogen sources. The properties of Co 3 O 4 /NDC composite and bare Co 3 O 4 are systematically characterized by X-ray diffraction, Raman spectrum, transmission electron microscopy (TEM), and scanning electron microscopy. TEM result indicates that the Co 3 O 4 particles are coated with a layer of nitrogen doped carbon film, with can enhance its conductivity and alleviate the volume effect. The results of electrochemical tests show that the discharge specific capacity of Co 3 O 4 /NDC composite is 1088 mAh g −1 of 0.1 C (1 C = 890 mA g −1 ) after 100 cycles. Compared to Co 3 O 4 /NDC composite, the discharge specific capacity of bare Co 3 O 4 is 628 mAh g −1 of 0.1 C after 100 cycles. The enhanced electeochemical properties can be attributed to the nitrogen doped carbon film that prevents the structure from being destroyed during lithium ion (Li + ) insertion/deinsertion process and improves the conductivity.