Supercapacitor Stack Built from Monolithic Porous Glassy Carbon Electrodes

Wednesday, 31 May 2017: 17:00
Churchill C1 (Hilton New Orleans Riverside)
A. Braun (Empa)
The inherent high porosity of glassy carbon, a monolithic carbon form, can be opened by various oxidation processes. I present a gasphase thermal oxidation process which has been shown easy and successful for the opening and connecting of IUPAC micropores in the nanometer range. The precise control of this carbon "actication" process allows for the engineering of monlithic bipolar electrode assemblies with high porosity carbon films on top and bottom with an electroncilly conducting and ionically blocking layer inbetween. Stacks of several such electrodes have been built and tested for 100,000 cycles.

I will also show the detailed pore building and connection process which was assessed with small angle xray scattering and cyclic voltametry and impedance spectropscopy. The charge carrier dynamics follows consequently the evolution of the pore space. A mathematical model is presented which precisely reflects the evolution of porous film thickness, pore growth and double layer capacity.

[1] A. Braun, J. Ilavsky, S. Seifert, Highly porous activated glassy carbon film sandwich structure for electrochemical energy storage in ultracapacitor applications: Study of the porous film structure and gradient, J. Mater. Res. (2010) 25(8) 1532-1540.