Grain boundary effects on Li-ion diffusion in a Li_1.2Co_0.13Ni_0.13Mn_0.54O₂ thin film cathode studied by scanning probe microscopy techniques

Abstract

This paper presents the results of in situ characterization of grain boundary effects on Li-ion diffusion in Li1.2Co0.13Ni0.13Mn0.54O2 thin film cathode by using various Scanning Probe Microscopy (SPM) techniques.

Advances in Understanding Materials for Rechargeable Lithium Batteries by Atomic Force Microscopy

“…LiNi 1−x−y Co y Mn x O 2 (NCM) has become one of the most promising cathode materials for next‐generation LIBs for high capacity, low cost, and improved safety compared with LiCoO 2 . Using c‐AFM, I–V curves show that grain boundaries have higher Li + diffusion rate and lower Li + diffusion energy barrier than grain interiors in Li 1.2 Co 0.13 Ni 0.13 Mn 0.54 O 2 like LiCoO 2 . The Li + diffusion is closely related to the changes in surface morphology, and bias‐induced Li + redistribution is partially reversible on Li 1.2 Co 0.13 Ni 0.13 Mn 0.54 O 2 cathode using ESM .…”

Probing of Local Multifield Coupling Phenomena of Advanced Materials by Scanning Probe Microscopy Techniques

“…Our researches in this area are mainly focused on all‐solid‐state full battery (SSFB), and single layer or nanoparticles of the electrode materials. SPM techniques, including ESM, KPFM, BE‐ESM, c‐AFM, and AM–FM, were applied to characterize the bias‐induced deformation, changes of conductivity and elasticity of SSFB ( Figure i) and electrodes due to the electrochemical charge/discharge processes …”

“…Besides SSFB, single‐layer cathode films, including LiCoO 2 , LiMn 2 O 4 , and others, were also extensively characterized by SPM techniques. Our works were mainly focused on layered‐oxide cathode materials . One of the works was to characterize the as‐deposited and cycled LiNi 1/3 Co 1/3 Mn 1/3 O 2 film using BE‐ESM and C‐AFM techniques .…”

“…BE‐ESM amplitude ( A ) can be related to the diffusion coefficient ( D ) bywhere ν is Poisson's ratio; β is the Vegard coefficient, which describes the linear relationship between the lithium‐ion concentration and the volume of the material for a continuous solid solution, with the value equals to 0.02349; V ac is the drive amplitude; ω is the frequency of the applied electric field; η is defined as a linear relationship between the potential at the tip and the concentration field of mobile ions, which can be determined by Butler‐Volmer voltage activation kinetics . When the ESM tip is taken as a reference, η can be set to equal to the applied voltage.…”

“…When the ESM tip is taken as a reference, η can be set to equal to the applied voltage. According to Equation , ESM amplitude image can be used to extract the local diffusion coefficient, and this was done for Li‐rich cathode film Li 1.2 Co 0.13 Ni 0.13 Mn 0.54 O 2 ( Figure i) . The diffusion coefficient determined from BE‐ESM image is in the same order of the macroscopic electrochemical measurements.…”