Mixed ion and electron conducting polymer composite membranes for artificial photosynthesis

Inspired by the fact that OH- has a very high mobility in water, highly conductive OH⁻conducting membranes were developed for alkaline water electrolysis. The membranes were semi-interpenetrating networks of crosslinked poly(vinyl alcohol) (PVA) and a polycation miscible with PVA. It is analogous to aqueous strong base solution. The polycation is a OH- containing polymer; PVA solvates this polycation and facilitates the ion conduction via Grotthuss mechanism. The membrane with proper composition has an exceptionally high OH⁻ conductivity of 151 mS/cm, 6.51 times as high as the commercial membrane Neosepta AHA. At the same time, the hydrogen bonds and covalent crosslinks in the system give this membrane a high tensile strength of 41 MPa in the wet state, 46% higher than the Neosepta AHA membrane. Insight in the ion conduction mechanism was gained by spectroscopic studies and the measurement of OH- conduction activation energy.

Name thesis:degree_name

Doctoral

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Materials Science and Engineering

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2019

Author dc:creator

• Zhang, Ketian.

Advisor dc:contributor.advisor

• Paula T. Hammond.

• Materials Science and Engineering.

Statement dc:rights

• MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/1721.1/121607

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/121607