Abstract
During LIB electrode manufacturing, it is difficult to avoid the certain defects that diminish LIB performance and shorten the life span of the batteries. This study provides a systematic investigation correlating the different plausible defects (agglomeration/blisters, pinholes/divots, metal particle contamination, and non-uniform coating) in a LiNi0.5Mn0.3Co0.2O2 positive electrode with its electrochemical performance. In addition, an infrared thermography technique was demonstrated as a nondestructive tool to detect these defects. The findings show that cathode agglomerates aggravated cycle efficiency, and resulted in faster capacity fading at high current density. Electrode pinholes showed substantially lower discharge capacities at higher current densities than baseline NMC 532electrodes. Metal particle contaminants have an extremely negative effect on performance, at higher C-rates. The electrodes with more coated and uncoated interfaces (non-uniform coatings) showed poor cycle life compared with electrodes with fewer coated and uncoated interfaces. Further, microstructural investigation provided evidence of presence of carbon-rich region in the agglomerated region and uneven electrode coating thickness in the coated and uncoated interfacial regions that may lead to the inferior electrochemical performance. This study provides the importance of monitoring and early detection of the electrode defects during LIB manufacturing processes to minimize the cell rejection rate after fabrication and testing.
Original language | English |
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Pages (from-to) | 70-79 |
Number of pages | 10 |
Journal | Journal of Power Sources |
Volume | 312 |
DOIs | |
State | Published - Apr 30 2016 |
Funding
This research at Oak Ridge National Laboratory, managed by UT Battelle, LLC, for the U.S. Department of Energy (DOE) under contract DE-AC05-00OR22725 , was sponsored by the Office of Energy Efficiency and Renewable Energy for the Vehicle Technologies Office's Applied Battery Research Program (Program Managers: Peter Faguy and David Howell). Scanning Electron Microscopy experiments were conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility. Debasish thanks Shawn Reeves for her help in collecting backscattered SEM images.
Keywords
- Capacity fade
- Electrode defect
- Lithium-ion battery
- Manufacturing
- Quality control