Multi-characterization of LiCoO₂ cathode films using advanced AFM-based techniques with high resolution

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Thin-film lithium-ion batteries are crucial for micro-electronic devices.
• Prolonging the operational lifetime of these batteries requires understanding cathode film aging mechanisms.

Purpose of the Study:

• To investigate the nanoscale aging mechanisms of lithium-cobalt oxide (LiCoO2) cathode films.
• To correlate microscopic surface changes with macroscopic capacity fade.

Main Methods:

• Multi-characterization using advanced Atomic Force Microscopy (AFM)-based techniques.
• Amplitude Modulation-Frequency Modulation (AM-FM) for surface morphology and contact stiffness.
• Kelvin Probe Force Microscopy (KPFM) for surface potential.
• Galvanostatic charge/discharge for macro-capacity measurement.

Main Results:

• Observed significant changes in surface morphology, contact stiffness, and surface potential after charge/discharge cycling.
• Detailed discussion of the intrinsic reasons behind these observed microscopic alterations.
• Correlation established between nanoscale changes and macro-capacity degradation.

Conclusions:

• The study provides deep insights into the fading mechanisms of LiCoO2 cathode films.
• Findings are valuable for the design and selection of cathode materials for high-performance thin-film batteries.