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Organic cathode materials have attracted significant research attention recently, yet their low electronic conductivity limits their application as solid-state cathodes in lithium batteries. This work describes the development of a novel organic cathode chemistry with significant intrinsic electronic conductivity for solid-state thin film batteries. A polymeric charge transfer complex (CTC) cathode, poly(4-vinylpyridine)-iodine monochloride (P4VP·ICl), was prepared by initiated chemical vapor deposition (iCVD). Critical chemical, physical, and electrochemical properties of the CTC complex were characterized. The complex was found to have an electronic conductivity of 4 × 10-7 S cm-1 and total conductivity of 2 × 10−6 S cm−1 at room temperature, which allows the construction of a 2.7 μm thick dense cathode. By fabricating a P4VP·ICl|LIPON|Li thin film battery, the discharge capacity of P4VP·ICl was demonstrated to be >320 mA h cm−3 on both rigid and flexible substrates. The flexible P4VP·ICl|LIPON|Li battery was prepared by simply replacing the rigid substrate with a flexible polyimide substrate and the as-prepared battery can be bent 180° while maintaining electrochemical performance.
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Chemomechanical behaviors of layered cathode materials in alkali metal ion batteries
Layered cathode materials (LCMs), because of their high energy density and relatively stable performance, represent an important class of cathode materials for alkali metal ion ( e.g. , Li + and Na + ) batteries. Chemomechanical behaviors of LCMs, which affect battery performance dramatically, have drawn extensive attention in recent years. Most chemomechanical processes have some common chemical and structural origins that are at the center of materials chemistry, for example, defects and local bonding environments in the solid state. In this review, we first discuss the chemomechanical breakdown of LCMs by introducing their categories and negative effects on the battery performance. We then systematically analyze factors that govern the initiation and propagation of chemomechanical breakdown and summarize their formation mechanisms. Strategies that can enhance the chemomechanical properties of LCMs or reduce the destructive effects of chemomechanical breakdown are then discussed. Finally, light is shed on the new state-of-the-art techniques that have been applied to study chemomechanical breakdown. This review virtually includes most aspects of the chemomechanical behaviors of LCMs and provides some insights into the important chemical motifs that determine the chemomechanical properties. Therefore, we believe that advanced design protocols of LCMs can be developed to effectively address the chemomechanical breakdown issue of LCMs.
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- Award ID(s):
- 1832613
- PAR ID:
- 10110400
- Date Published:
- Journal Name:
- Journal of Materials Chemistry A
- Volume:
- 6
- Issue:
- 44
- ISSN:
- 2050-7488
- Page Range / eLocation ID:
- 21859 to 21884
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/C8TA06875E
