About CMC as a binder in the evaluation for an electric double layer capacitor


Yamagata University Faculty of Engineering Department of Chemical Engineering substance 3 years　Daiki Kurosawa


Experimental purposes
　Well as assessing the applicability for various CMC (carboxymethyl cellulose), and subjected to electrochemical measurements, The CMC that does not degrade the electrical performance I seek the ideal of slurry designs that thickener.

Battery-powered

Al｜CMC1190,CNT,SBR｜5wt%AA｜SuS
Al｜CMC2200,CNT,SBR｜5wt%AA｜SuS

Experimental methodology
CNT, SBR, the slurry that was created by mixing the CMC is applied to the aluminum foil, you have created a positive electrode.
  Then, I went the CV measurement of two of the positive electrode.

○Adjustment of slurry
CMC2200, CMC1190 respectively 0.007g, was weighed 0.005g, 10 drops of water each, were added and stirred CNT, the SBR.
This time towards CMC2200 is I was found to be higher viscosity than CMC1190.

○Creating a positive electrode
　Was applied respectively to create slurry to two of aluminum foil.
　CMC1190 when it was applied, it was hard to can be easily uneven coating.
　CMC2200 when it was applied, was easy can be difficult uneven coating.

○CV measurement
First, I have to adjust the AAaq of 0.3M. After creating a double layer capacitor so as to be in the above battery-powered, and was measured CV.
・CMC1190
Capacitance of the capacitor is the minimum value of the cathode side 51.0mV, -135μA, the anode side of the maximum 996mV, was 134μA.
・CMC2200
Capacitance of the capacitor is the minimum value of the cathode side 46.1mV, -156μA, the anode side of the maximum 231mV, was 954μA.


The results
The relationship between the capacitance and the CNT coating amount of the CMC obtained from the measured values are shown below.

ThickenerCapacitance/mFCNT coating amount/mg
CMC11900.258.4
CMC22001.085.9


　The results, simply look if as towards CMC2200 binders because it is can be seen high capacitance per CNT coating amount of CMC2200 Performance I considered high.
However, during the experiment air bubbles from the electrode occurs has been confirmed using CMC2200.
In this case, bubbles the anodic oxidation reaction Possibility that inhibit it can be inferred that higher. Also, if it was used in a battery or the like CMC2200, accumulate gas therein by air bubbles generated There is a risk of explosion.
Another, CMC2200 when the slurry adjustment was difficult mix very when stirred with water. From the above, when comparing the two CMC, is considered a person CMC1190 is easily used as a binder.