A parallel-plate RF probe and battery cartridge for ⁷Li ion battery studies

Area of Science:

• Materials Science
• Electrochemistry
• Analytical Chemistry

Background:

• Magnetic Resonance (MR) and Magnetic Resonance Imaging (MRI) are powerful tools for studying lithium-ion (Li-ion) battery materials.
• Existing MR-compatible battery cells often have limitations in geometry, sample volume, and operational flexibility, hindering detailed in situ and ex situ analysis.

Purpose of the Study:

• To introduce a new parallel-plate resonator and a removable cartridge-like electrochemical cell for advanced ⁷Li ion cell and lithium-ion battery studies.
• To enable charge/discharge outside the magnet, facilitate sample multiplexing, and improve upon traditional MR-compatible battery designs.
• To demonstrate the capability for high-resolution ⁷Li profiling and T₁-T₂ relaxation correlation experiments within a Li-ion cell.

Main Methods:

• Development of a parallel-plate resonator with a cartridge-like electrochemical cell designed for Li-ion battery research.
• Utilizing the new cell geometry, which places electrodes parallel to the B₁ magnetic field to minimize RF attenuation.
• Acquisition of ex situ and in situ 1D ⁷Li profiles and T₁-T₂ relaxation correlation experiments.

Main Results:

• Demonstrated ex situ and in situ 1D ⁷Li profiles with a nominal resolution of 35 µm at 38 MHz.
• Successfully performed the first T₁-T₂ relaxation correlation experiment within a Li-ion cell.
• T₁-T₂ correlation maps indicated the detection of lithium intercalated into graphite and other Li species.

Conclusions:

• The new parallel-plate resonator and cartridge-like cell offer a significant advancement for MR/MRI studies of Li-ion batteries.
• The design overcomes limitations of previous cells, allowing for greater operational flexibility and improved sample volume.
• This methodology shows promise for detailed characterization of lithium species and their behavior during battery operation.