3D Correlative Imaging of Lithium Ion Concentration in a Vertically Oriented Electrode Microstructure with a Density...

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Lithium-ion battery (LIB) performance is limited by lithium-ion concentration gradients, especially in thick electrodes.
• Thick electrodes offer higher energy density but worsen ion diffusion challenges.
• Existing methods for studying ion diffusion primarily rely on computational modeling due to the low atomic number of lithium.

Purpose of the Study:

• To develop an experimental method for visualizing lithium-ion concentration distribution within LIB electrodes in working coin cells.
• To correlate electrode microstructure with lithium-ion transport and electrochemical performance.
• To investigate strategies for mitigating concentration gradients in ultra-thick electrodes.

Main Methods:

• Development of an interrupted in situ correlative imaging technique.
• Combination of full-field X-ray Compton scattering imaging and X-ray computed tomography.
• 3D pixel-by-pixel mapping of Li+ stoichiometry and electrode microstructure in a LiNi0.8Mn0.1Co0.1O2 cathode within a working coin cell.

Main Results:

• Fabrication of an electrode microstructure with vertically oriented pore arrays and a density gradient.
• Demonstration of improved Li+ ion diffusivity and homogenized Li+ ion concentration across a 1 mm thick electrode.
• Enhanced utilization of active materials in the ultra-thick electrode.

Conclusions:

• The novel imaging technique provides unprecedented insight into Li+ ion distribution in thick LIB electrodes.
• Designed electrode microstructures can effectively homogenize ion concentration and improve performance.
• This approach facilitates the development of high-energy-density LIBs with thick electrodes.