POLY(ETHYLENIMINE)-BASED ELECTROLYTES FOR BATTERIES AND FUEL CELLS: SYNTHESIS, MODIFICATION AND CHARACTERIZATION

Poly(ethylenimine) (PEI) is an ion conducting polymer with great potential for applications in lithium batteries and proton exchange membrane fuel cells. Branched poly(ethylenimine) was N—methylated via an Eschweiler—Clarke reaction to produce branched poly(N—methylethylenimine), BPMEI. Novel alkylated linear poly(N—ethylethylenimine), LPEEI, and linear poly(N—butylethylenimine), LPBEI, were synthesized from linear poly(ethylenimine), LPEI, via reductive amination of aliphatic aldehydes. Differential scanning calorimetry was used to determine the glass transition temperature, Tg, of neat BPMEI (Tg = – 91°C), LPEEI (Tg = – 80°C) and LPBEI (Tg = – 50°C). Tgs of various N—alkylated PEI—lithium triflate complexes with different salt concentrations were determined. BPMEI exhibits a greater Tg change upon lithium triflate addition (from – 91°C to 13°C) than that of LPMEI complexes (from – 93°C to – 14°C). It was found that LPEEI complexes showed higher Tgs at all salt concentrations than the corresponding LPMEI—LiSO3CF3 system. IR and Raman spectroscopy were used to study complexes of these polymers with lithium triflate for battery applications. Vibrational spectra of BPMEI—LiSO3CF3 complexes reveal that aggregate formation is not observed until salt concentration reaches 5:1 (N:Li molar ratio). Additionally, a decrease in the relative concentration of “free” ions, compared to equivalent linear systems, is observed. LPEEI’s spectra presented few changes upon salt addition, suggesting that salt addition causes less disruption of the local polymer microstructure than that observed in LPMEI systems in previous studies.

Author dc:creator

• Yepez Castillo, Frank Isaias

Advisor dc:contributor.advisor

• Glatzhofer, Daniel T.

• Polyelectrolytes
• Fuel cells
• Electric batteries

Language dc:language

en_US

Identifier

99214263002042

OAI record oai:identifier

https://shareok.org/server/oai/request?verb=GetRecord&metadataPrefix=dim&identifier=oai%3Ashareok.org%3A11244%2F318764