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Electronic connections between active material particles and the conductive carbon binder domain govern high-energy commercial Li-ion batteries' rate capability and lifetime (LIB). This work develops an in situ electrochemical fluorescent microscopy (EFM) technique that maps fluorescence intensity to these local electronic connections. Specifically, rapid redox kinetics of an electrofluorophore translates to reaction distributions limited by the electronic accessibility of battery electrode regions and individual active material particles. This technique can visualize hot spots, dead zones, and isolated particles on the electrode surface. EFM characterization of a series of LiNi0.33Mn0.33Co0.33O2electrodes across processing parameters finds a significant negative correlation between the number of disconnected active particles and the rate capability. This low-cost technique provides quantitative mesoscale characterization of commercial LIB electrodes with fast throughput (<60 s) to facilitate rapid research and development and provide manufacturing quality control.
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Understanding Interfacial‐Energy‐Driven Dry Powder Mixing for Solvent‐Free Additive Manufacturing of Li‐Ion Battery Electrodes
Abstract Lithium‐ion battery electrodes are manufactured using a new additive manufacturing process based on dry powders. By using dry powder‐based processing, the solvent and its associated drying processes in conventional battery process can be removed, allowing for large‐scale Li‐ion battery production to be more economically viable in markets such as automotive energy storage systems. Uniform mixing distribution of the additive materials throughout the active material is the driving factor for manufacturing dry powder‐based Li‐ion batteries. Therefore, this article focuses on developing a physical model based on interfacial energies to understand the mixing characteristics of the dry mixed particulate materials. The mixing studies show that functional electrodes can be manufactured using dry processing with binder and conductive additive materials as low as 1 wt% due to the uniformly distributed particles. Electrochemical performance of the dry manufactured electrodes with reduced conductive and binder additive is promising as the cells retained 77% capacity after 100 cycles. While not representative of the best possible electrochemical performance of Li‐ion batteries, the achieved electrochemical performance of the reduced conductive and binder additive electrodes with LiCoO2as the active material confirms the well distributed nature of the additive particles throughout the electrode matrix.
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- Award ID(s):
- 1640647
- PAR ID:
- 10234662
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials Interfaces
- Volume:
- 4
- Issue:
- 21
- ISSN:
- 2196-7350
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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