College of

Engineering, Architecture and Technology

 

Light-mediated Energy to Accelerate Li-ion Battery Electrochemical Reactions

April 11, 3:00pm
Engineering North 107

 

Fast-charging batteries are critical to consumer acceptance in the electric vehicle marketplace. Recently, we demonstrated that under white light illumination LiMn204 cathodes undergo photo-accelerated fast charging, essentially improving the kinetics of delithiation electrochemical reaction without use of nanostructured active 
materials.  [1] Recently this energy of irradiation has been shown to be coupled to Red LED light radiance at the electrode surface. In this work, we further probe the driving force behind photo-accelerated fast charging using LEDs to select discrete wavelengths of light, this time in a demonstration with the Li4Ti5 012 spinel anode compared to the dark state. A faster charging speed of about 17% is seen when UV light is used versus dark state, but also interestingly the charging current rate remains the same as dark when the light energy (such as Red light) is not electronically coupled to the material band gap. We propose that the band gap of Li4Ti5 012 is better matched to 
the incident energy of UV light commiserate with an initial bandgap of approximately 3 eV. It appears that photo accelerating electrochemical reactions in batteries are associated with electron-hole formation in intrinsically wide-band gap insulators or semiconducting materials.  [2] The design of how to integrate light into a battery pack, 
however, will be critical in rolling out this technology for real world application.

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Chris Johnson is currently an Argonne Distinguished Fellow and senior chemist at 
Argonne National Laboratory, specializing in the research & development of battery 
materials and battery systems with 30 years of experience. He is known worldwide for 
his development of state-of-art lithium-ion battery cathode materials, and sodium-ion 
batteries. Recently he has been interested in accelerating electrochemical reactions with light. He holds a BS. Chemistry from the University of North Carolina at Chapel Hill and a Ph.D. in Chemistry from Northwestern University. He has published over 140 publications, and 34 issued US patents in the battery field. He has received the research award from the International Battery Association in 2006, and a R&D-100 award for the commercialization of lithium battery materials in 2009. He is Past-Chair of the Electrochemical Society Battery Division, and immediate past President of the International Battery Association (IBA). He is the 2018 recipient of the University of Chicago Argonne Distinguished Scientist Award, and is a Fellow of the Electrochemical Society.