Effect of Metal (Mn, Ti) Doping on NCA Cathode Materials for Lithium Ion Batteries

Abstract

NCA (LiNi 0.85 Co 0.10 Al 0.05−x M x O 2 , M=Mn or Ti, < 0.01) cathode materials are prepared by a hydrothermal reaction at 170 ∘ C and doped with Mn and Ti to improve their electrochemical properties. The crystalline phases and morphologies of various NCA cathode materials are characterized by XRD, FE-SEM, and particle size distribution analysis. The CV, EIS, and galvanostatic charge/discharge test are employed to determine the electrochemical properties of the cathode materials. Mn and Ti doping resulted in cell volume expansion. This larger volume also improved the electrochemical properties of the cathode materials because Mn 4+and Ti 4+ were introduced into the octahedral lattice space occupied by the Li-ions to expand the Li layer spacing and, thereby, improved the lithium diffusion kinetics. As a result, the NCA-Ti electrode exhibited superior performance with a high discharge capacity of 179.6 mAh g −1 after the first cycle, almost 23 mAh g −1 higher than that obtained with the undoped NCA electrode, and 166.7 mAh g −1 after 30 cycles. A good coulombic efficiency of 88.6% for the NCA-Ti electrode is observed based on calculations in the first charge and discharge capacities. In addition, the NCA-Ti cathode material exhibited the best cycling stability of 93% up to 30 cycles.

Systematic Study of Al Impurity for NCM622 Cathode Materials

“…As reported in the previous work, the cation mixing caused by a similar radius of Li + and Ni 2+ ions would inhibit the transfer of Li ions in the Li layer of the NCM cathode particles, which leads to non-negligible negative impacts on the electrochemical performance, especially the rate capability and cycling stability. 50,51 The value of cation mixing degree for the 0.2ANCM cathode sample is the lowest, which suggests that the 0.2ANCM cathode sample would display better performance in the latter electrochemical test than other prepared cathode electrodes.…”

The role of metal substitutions in the development of Li batteries, part I: cathodes

“…This expands the interlayer distance, allowing for easier Li + movement as well as reducing the severity of Li/Ni mixing. 210,232 Liu et al have found the concentration of 1% atom to be optimal. Ti may also act as ''pillar'' ions, supporting the structure through repeated lithiation/delithiation and preventing collapse.…”

Review of Modified Nickel-Cobalt Lithium Aluminate Cathode Materials for Lithium-Ion Batteries

“…Mn and Ti have atomic radii similar to Ni and coordinate with oxygen to replace transition metal atoms in octahedral interstitial sites. Wan et al [82] prepared a LiNi 0.85 Co 0.1 Al 0.05 O 2 (NCA) cathode material by hydrothermal reaction and doping with the transition metals Mn and Ti, respectively. In the voltage range of 3.0-4.3 V, the initial discharge specific capacity of NCA-Ti and NCA-Mn was 179.6 mAh g -1 and 171.4 mAh g -1 , respectively, which was higher than that of undoped NCA (156.5 mAh g -1 ).…”