Nano Co 3 O 4 as Anode Material for Li–Ion and Na‐Ion Batteries: An Insight into Surface Morphology

Co 3 O 4 is regarded as a competent anode material for lithium and sodium ion batteries having high theoretical capacity of 890 mAh g ‐1 obtained through metal displacement reaction with Li or Na. Nano Co 3 O 4  consisting of 20–30 nm‐sized particles was synthesized through a simple precipitation method and characterized through X‐ray diffraction, Fourier‐transform infrared spectroscopy, scanning electron microscopy, Transmission electron microscopy and X‐ray photoelectron spectroscopy. Electrochemical evaluation of the nano Co 3 O 4 as anode material for Li‐ion and Na‐ion batteries was performed through cyclic voltammetry, electrochemical impedance spectroscopy and charge‐discharge cycling studies. Nano Co 3 O 4 delivered high discharge capacity of 423 mAh g ‐1 at 0.1 C even after 40 cycles as Li‐ion battery anode and exhibited stable discharge behaviour up to 130 cycles with high rate capability. Nano Co 3 O 4 in Na‐ion configuration delivered discharge capacity of 101 mAh g ‐1 at 0.1 C rate even after 30 cycles. At higher current rates Co 3 O 4 electrodes exhibited severe capacity fading due to the huge volume change occurred during sodiation / desodiation. Ex‐situ SEM and elemental analyses evidenced that disintegration of electrode structure resulting from volume change and continuous decomposition of electrolyte were responsible for the poor electrochemical performance of Co 3 O 4 with Na + ions while in Li‐ion configuration nano Co 3 O 4 outshined in cycling performance.