Effect of TiO_x Surface Modification on the Electrochemical Performances of Ni-Rich (NMC-622) Cathode Material for Lithium-Ion Batteries

Abstract

Ni-rich layered lithium transition metal oxides (LiNi x Mn y Co z O2) have gained significant attention as high-capacity positive electrode materials for lithium-ion batteries. However, their poor cyclability, capacity retention, and rate capability at higher working potentials limit their applications in commercial batteries. Here, we demonstrate a cost-effective chemical solution deposition route of a thin TiO x shell on LiNi0.6Mn0.2Co0.2O2 (NMC-622) particles and the effect of surface modification on the electrochemical properties. The crystallinity and morphology of the NMC-622 particles are unaffected by the deposition step and verified by powder X-ray diffraction and electron microscopy. High-resolution transmission electron microscopy (HR-TEM) and selected area electron diffraction (SAED) analysis showed that the TiO x surface layer is amorphous and prone to enhance the electronic conductivity of the cathode material. The TiO x -coated material has an improved rate performance and experiences a lower charge-transfer resistance compared to the pristine material. The effect of the surface modification on the electrochemical performance of NMC-622 was investigated further by the assembly of NMC-622/Li4Ti5O12 (LTO) full cells. The beneficial impact of the TiO x coating on the electrochemical performance of NMC-622 positive electrodes in lithium-ion battery applications was showcased by the higher initial Coulombic efficiency and lower aging rates during 150 cycles at 1C in NMC-622/LTO cells.

One-pot synthesis of LiAlO2-coated LiNi0.6Mn0.2Co0.2O2 cathode material

“…4, the synthetized samples present a homogeneous particles' morphology for each material. Moreover, the appearances of all three NMC samples are similar, and they exhibit spherical secondary particles that are 10-14 µm in diameter, which is the standard particle size found in literature [38]. Correspondingly, Fig.…”

“…Moreover, the appearances of all three NMC samples are similar, and they exhibit spherical secondary particles that are 10-14 mm in diameter, which is the standard particle size found in literature. 38 Correspondingly, Fig. 4(g and h) shows the EDX mapping of a single particle for both coated samples presenting the elemental distribution.…”

“…Moreover, the appearances of all three NMC samples are similar, and they exhibit spherical secondary particles that are 10–14 μm in diameter, which is the standard particle size found in literature. 38…”

Impact of Different Conductive Polymers on the Performance of the Sulfur Positive Electrode in Li–S Batteries

“…The electronic conductivity measurements were performed on the powder samples using a home-built setup. Further details are presented in Figure S1b and the recently published article. , The MICROTRAC (S3500) particle size analyzer was used to measure the particle size dispersion (PSD) of the coated and uncoated sulfur powders. To study the structural phases in each sample, X-ray diffraction (XRD) patterns were recorded using an Empyrean diffractometer with monochromatic Co K α radiation at 40 mA and 45 kV.…”