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Surface Engineering of a LiMn 2 O 4 Electrode Using Nanoscale Polymer Thin Films via Chemical Vapor Deposition Polymerization
Surface engineering is a critical technique for improving the performance of lithium-ion batteries (LIBs). Here, we introduce a novel vapor-based technique, namely, chemical vapor deposition polymerization, that can engineer nanoscale polymer thin films with controllable thickness and composition on...
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Published in: | ACS applied materials & interfaces 2018-08, Vol.10 (32), p.27063-27073 |
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Main Authors: | , , , |
Format: | Article |
Language: | English |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Surface engineering is a critical technique for improving the performance of lithium-ion batteries (LIBs). Here, we introduce a novel vapor-based technique, namely, chemical vapor deposition polymerization, that can engineer nanoscale polymer thin films with controllable thickness and composition on the surface of battery electrodes. This technique enables us to, for the first time, systematically compare the effects of a conducting poly(3,4-ethylenedioxythiophene) (PEDOT) polymer and an insulating poly(divinylbenzene) (PDVB) polymer on the performance of a LiMn
O
electrode in LIBs. Our results show that conducting PEDOT coatings improve both the rate and the cycling performance of LiMn
O
electrodes, whereas insulating PDVB coatings have little effect on these performances. The PEDOT coating increases 10 C rate capacity by 83% at 25 °C (from 23 to 42 mA h/g) and by 30% at 50 °C (from 64 to 83 mA h/g). Furthermore, the PEDOT coating extends the high-temperature (50 °C) cycling life of LiMn
O
by over 60%. A model is developed, which can precisely describe the capacity degradation exhibited by the different types of cells, based on the aging mechanisms of Mn dissolution and solid-electrolyte interphase growth. Results from X-ray photoelectron spectroscopy suggest that chemical or coordination bonds form between Mn in LiMn
O
and O and S in the PEDOT film. These bonds stabilize the surface of LiMn
O
and thus improve the cycling performance. In contrast, no bonds form between Mn and the elements in the PDVB film. We further demonstrate that this vapor-based technique can be extended to other cathodes for advanced LIBs. |
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ISSN: | 1944-8244 1944-8252 |
DOI: | 10.1021/acsami.8b08711 |