A facile nitrogen-doped carbon encapsulation of CoFe2O4 nanocrystalline for enhanced performance of lithium ion battery anodes

Nitrogen-doped (N-doped) carbon encapsulation of CoFe2O4 nanocrystalline is achieved by a simple pressure-assisted pyrrole pyrolysis method. The CoFe2O4/N-doped carbon nanocomposite (CFO/NC) delivers a capacity of 646.2 mAh g(-1) after 80 cycles at 0.1 C, exhibits stable cycling performance at various rates from 0.2 to 1.6 C and retains a capacity of 662.8 mAh g(-1) as the rate returns back to 0.1 C, showing significantly improved lithium storage reversibility compared to the bare CFO. A different lithiation mechanism of CFO/NC above and below the plateau relative to CFO in the first discharge is analyzed in detail based on the potential profiles and cyclic voltammogram curves. Morphology characterization of the cycled electrodes confirms much better integrity of CFO/NC electrode due to the buffer effect of N-doped carbon coating. Electronic conductivity and electrochemical impedance spectroscopy measurements indicate enhanced electrode reaction kinetics of CFO/NC. All the results contribute to its improved electrochemical performance.