Synthesis of Li-excess layered cathode material with enhanced reversible capacity for Lithium ion batteries through the optimization of precursor synthesis method

Abstract Li x Ni 1/3 Mn 2/3 O 2 cathode materials have been synthesized through a facile reduction-ion exchange of P3-Na 2/3 Ni 1/3 Mn 2/3 O 2 precursors prepared by solid state (SS), spray dry (SD) and co-precipitation (CP) methods. The influence of precursor synthesis method on the structure, morphology and electrochemical performances of Li x Ni 1/3 Mn 2/3 O 2 has been investigated. X-ray diffraction (XRD) results of Li x Ni 1/3 Mn 2/3 O 2 demonstrate that all the samples exhibit similar XRD patterns as those of Lithium-excess layered cathode materials. Scanning Electron Microscope (SEM) images and Brunauer-Emment-Teller (BET) results present that the particle size, particle aggregation and surface area changed greatly with the precursor synthesis method. Galvanostatic charge-discharge results show that Li 1.41 Ni 0.32 Mn 0.66 O 2+δ cathode prepared from co-precipitation precursor exhibited high first discharge capacity of ca. 270 mAhg −1 with an initial cycle efficiency as high as 98%. The discharge capacity of Li 1.41 Ni 0.32 Mn 0.66 O 2+δ cathode after 30 cycles is over 250 mAhg −1 and it can deliver a discharge capacity roughly 210 mAhg −1 at a current density of 500 mAg −1 (2 C rate). Also, it was found that Li 1.41 Ni 0.32 Mn 0.66 O 2+δ cathode shows enhanced electrochemical performance over the Li 2/3 Ni 1/3 Mn 2/3 O 2 cathode with respect to reversible capacity and rate capability.