Conducting cellulose composites are promising sustainable functional materials that have found application in energy devices, sensing and water purification. Herein, conducting aerogels are fabricated based on nanofibrillated cellulose and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate, using the ice templating technique, and their bulk morphology is characterized with X-ray microtomography. The freezing method (-20 degrees C in a freezer vs liquid nitrogen) does not impact the mean porosity of the aerogels but the liquid-N2 aerogels have smaller pores. The integration of carbon fibers as addressing electrodes prior to freezing results in increased mean porosity and pore size in the liquid-N2 aerogels signifying that the carbon fibers alter the morphology of the aerogels when the freezing is fast. Spatially resolved porosity and pore size distributions also reveal that the liquid-N2 aerogels are more inhomogeneous. Independent of the freezing method, the aerogels have similar electrochemical properties. For aerogels without carbon fibers, freezer-aerogels have higher compression modulus and are less stable under cycling compression fatigue test. This can be explained by higher porosity with larger pores in the center of liquid-N2 aerogels and thinner pore walls. This work demonstrates that micro-CT is a powerful tool for characterizing the morphology of aerogels in a non-destructive and spatially resolved manner. Conducting aerogels based on nanofibrillated cellulose and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate are fabricated with the ice templating technique and their bulk morphology is characterized in a spatially resolved manner with X-ray microtomography. The effect of the freezing temperature and the integration of carbon fibers electrodes prior to freezing on the morphology, mechanical, and electrochemical properties is examined.
Funding Agencies|Wallenberg Wood Science Center [KAW 2018.0452]; European Unions Horizon 2020 research and innovation programme (FET-OPEN-HyPhOE) [800926]; Swedish Research Council [VR-2017-04910, VR 2022-03507]; Swedish Foundation for Strategic Research [ID17-0097, FFL-18-0101]; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University [2009-00971]