Novel solid-state preparation and electrochemical properties of Li1.13[Ni0.2Co0.2Mn0.47]O2 material with a high capacity by acetate precursor for Li-ion batteries

Abstract

The new lithium-rich cathode Li1.13[Ni0.2Co0.2Mn0.47]O2 powders are synthesized by novel solid-state method, which adopts the acetate precursors compounded thoroughly on the alcohol solvent. The prepared Li-rich NCM can also be equivalently noted as 0.4Li[Li1/3Mn2/3]O2 · 0.6Li[Ni1/3Co1/3Mn1/3]O2 by solid solution notation. The product is characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) to determine its structure and morphology. XRD data reveal a well-crystallized Li-rich NCM with mainly typical α-NaFeO2 layered structure (R3¯m space group). The morphology studied by SEM shows homogeneous primary particles in good distribution size (80–250 nm) with small aggregates, benefiting the charge–discharge feature and electrochemical performance. Electrochemical tests are carried out in the voltage cutoff range of 2.0–4.8 V vs. Li/Li+ by varied C-rates at room temperature. The initial reversible capacity can be achieved as high as 218.2 mAh g− 1 at 0.1 C with good capacity retention after 50 cycles. In order to further understand the electrochemical process of this cathode material during charge–discharge cycling, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) are employed to investigate electrochemical parameters like lithium ion diffusion coefficient DLi and charge transfer resistance Rct to confirm the good capacity performance. In consideration of the economy and preparation feasibility on large-scale commercialization for lithium ion battery cathode with excellent electrochemical performance, this Li1.13[Ni0.2Co0.2Mn0.47]O2 cathode prepared by its acetate precursor has showed its great advantages on high capacity and good capacity retention.