I prepare a 3D printed electrode for micro battery application. But it develops many cracks (shown in the image below) after drying at a very low temperature of around 35 degrees Celsius.
My ink contains active material (70%), binder (10%), carbon nanotube (10%), and Graphene oxide (10%). The solvent is either NMP or DMF, and the substrate is a Polyimide sheet.
Please suggest a way to overcome this issue.
Yusuf Khan 3D printed electrodes may develop cracks after 35°C drying due to solvent evaporation, capillary stress, thermal expansion/contraction, and chemical incompatibility. These factors can cause shrinkage, pull on the surrounding material, thermal expansion/contraction stress, and chemical reactions.
Yusuf Khan Use a less volatile solvent (DMSO or PEG can potentially reduce cracking in ink), add plasticizer, change the binder (PVDF (polyvinylidene fluoride), PEO (polyethylene oxide), CMC (carboxymethyl cellulose), SBR (styrene-butadiene rubber) or PTFE (polytetrafluoroethylene), and modify the composition of the ink to reduce solvent evaporation in order to prevent ink cracking.
I hope this helps you. Best wishes.
Thank you, Alvena Shahid, for your suggestion. I have one question, at the end, we want to evaporate the solvent to fully dry the 3D structure then what do you mean by reduced solvent evaporation?
Thanks
It looks like your binder might be evaporating. Make sure it is not your binder that is evaporating. If your binder evaporated, then it's no longer there and not working for your mixture anymore (not binding your mixture anymore...and hence cracking). If your binder is not evaporating, then try a more compatible binder so the binder works properly and then cracks would not form. Try less solvent (use the minimum of solvent to prevent cracking after drying) and try a more compatible solvent too.
You may try a different way to dry your electrode. For example: use liquid N2 to promote direct water sublimation (it may be more gentle and faster drying process). Another way: vacuum oven drying (speed up the drying process and prevent binder and other materials separation).
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