Scanning Probe Microscopy Facility for Operando Study of Redox Processes on Lithium ion Battery Electrodes.

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Battery research requires advanced techniques for analyzing electrochemical properties at high resolution.
• Current methods often face limitations in simultaneous topological and electrochemical data acquisition.
• Atomic Force Microscopy (AFM) offers high spatial resolution but needs integration with electrochemical measurement capabilities.

Purpose of the Study:

• To develop an integrated Atomic Force Microscope (AFM) system for in-situ electrochemical measurements in battery research.
• To create a lithiated probe for active element measurements, enabling simultaneous topological and electrochemical analysis.
• To establish a robust method for measuring and monitoring the lithiation process on the AFM probe tip.

Main Methods:

• Coupling an AFM with a glovebox system and a Galvanostat/Potentiostat for electrochemical measurements.
• Utilizing an open cell design for direct cantilever access to the electrode surface during battery operation.
• Developing and comparing "dry methods" for applying lithium to the AFM probe tip, with metallic lithium application and silicon alloy formation identified as optimal.
• Employing resonance frequency shift measurements and Finite Element Method (FEM) modeling to quantify lithiation on the probe tip.
• Performing electrochemical measurements, including ion current tracking and electrochemical impedance analysis, using the lithiated probes.

Main Results:

• Successful integration of AFM with electrochemical measurement tools for battery research.
• Identification of "dry methods" as superior to "wet methods" for probe lithiation, with metallic lithium application and silicon alloy formation being most effective.
• Demonstration of the ability to monitor the lithiation process on the probe tip via resonance frequency shifts.
• Initial measurements showing the capability to track ion currents and perform electrochemical impedance analysis without interfering Redox-probes.
• Validation of the FEM-based probe model for simulating mass change effects on resonance frequency.

Conclusions:

• The developed AFM-Galvanostat/Potentiostat setup enables simultaneous topological and electrochemical measurements with high spatial resolution.
• The active lithiated probe method overcomes limitations of previous techniques, offering precise analysis during battery operation.
• This approach provides a powerful new tool for understanding battery degradation mechanisms and optimizing battery performance.
• The methodology is extendable to other AFM-based techniques for mapping electrochemical processes at the nanoscale.