V.H. Nguyen, M.L.P. Le, L.T.N. Huynh, V.M. Tran
Vietnam National University - Ho Chi Minh City, VN
cathode material, insertion-desinsertion mechanism, NaxMO2, sodium-ion batteries
NaxMO2 with M = Mn and Co as cathode materials in sodium-ion batteries was synthesized by solid-state reaction at 600-850oC. The manganese precursors was MnO2 obtained from electrolysis of MnSO4, MnCO3 and Mn(OAc)2 solutions. The structure of the as-prepared cathode materials was determined by X-ray diffraction (XRD) and the morphology was investigated by scanning electron microscope (SEM). The electrochemical properties were examined in 1 M NaClO4/PC as electrolyte by cyclic voltammetry (CV). The electrochemical behaviour of synthesized materials exhibit complex insertion-desinsertion mechanism in the potential window of 2 - 3.8 V vs Na+/Na with multi-peak in CV curves. These peaks correspond to the phase transition with sodium content. XRD patterns of manganese compounds showed that they are well crystallized in the same structure and the compound formed with Mn(OAc)2 precusor has the best crystallinity.