Why you did not measure the surface area of the concerned materials? It should be easy to do by nitrogen adsorption technique.

It is easy if you have the instrument handy but expensive if you have to pay for it to be done elsewhere. We currently do not have the instrument and all quotes we have received are pretty pricy for now.

Santosh, do you mean 78 - 100 m2/g ? If you are publishing your paper anytime soon, I could obtain the exact value and cite it.

Thank you

To my mind the best way is addressing of your question to the producer: SGL Carbon Group. The specific surface on level 100 sq.m/g is typical for the Russian graphite felt NTM200.

I am also supporting Dr.Isaian Owusu Gyan.

I have made several phone calls to the company. They keep passing the call on to the 'guy' who should know and nothing is coming out of it. I am guessing the SGL branch that I obtained the sample from (PA, USA), does not know the area, probably because they did not manufacture the felt here.

The best way to measure the surface area of this graphite felt is Mercury injection apparatus, instead of nitrogen adsorption technique. However, we did not have the data due to the shortage of this equipment.

Dear all,

I am interested in the properties of Graphite felt (KFD 2.5 EA)  by the SGL Carbon group. Can someone help me with information about the electrochemical properties of this material?

Thanks a lot,

Sindy Tarazona-Cardenas

Dear all, 

There are several papers describing the properties of carbon felt electrodes. 

1. González-García J, Bonete P, Expósito E, Montiel V, Aldaz A, Torregrosa-Maciá R. Characterization of a carbon felt electrode: structural and physical properties. J Mater Chem. 1999;9(2):419–26.

1. Carta R, Palmas S, Polcaro AM, Tola G. Behaviour of a carbon felt flow by electrodes Part I: Mass transfer characteristics. J Appl Electrochem. Kluwer Academic Publishers; 1991 Sep;21(9):793–8.

1. Qiu G, Dennison CR, Knehr KW, Kumbur EC, Sun Y. Pore-scale analysis of effects of electrode morphology and electrolyte flow conditions on performance of vanadium redox flow batteries. J Power Sources. 2012 Dec;219:223–34.

I don't have much time know but if you google "vanadium flow battery" surface area of carbon felt, you will find several papers, some of them on modelling, reporting recent estimations of the surface area of the SGL felts (in some cases they used the figures reported in the first two papers)

Given the large surface area of the felt, its effective electrochemical active area can be extremely difficult to measure. Hence, the volumetric mass transport coefficient can be used kmAe instead.

An important thing to note is that the surface area, permeability, porosity, tortuosity, resistivity against the current collector, etc. will change for different grades of compression.