Enabling high areal capacitance in electrochemical double layer capacitors by means of the environmentally friendly starch binder

• Potatoes starch is proposed as superior water-processable binder for electrochemical double layer capacitors.
• The presence of amylopectin provides enhanced mechanical properties and suppresses the cracking of the electrode.
• Potatoes starch enables considerably higher electrode loadings resulting on increased areal capacitance.

Potatoes starch (PS), a natural polymer obtainable from non-edible sources, is for the first time evaluated as alternative water-processable binder for Electrochemical Double-Layer Capacitor (EDLC) electrodes. Morphological and electrochemical properties of activated carbon (AC)-based electrodes are investigated and compared to those achieved with the state-of-the-art aqueous binder (CMC, i.e. Na-carboxymethyl cellulose). The obtained results suggest substantial benefits of PS, in particular regarding the electrode fabrication process. As a matter of fact, owing to its amylopectin content (moderately branched polysaccharide), PS displays only minimal shrinkage upon drying, resulting on rather homogeneous electrodes not presenting the dramatic surface cracking observed with CMC. Furthermore, owing to the smaller volume of water required for the processing, much higher active material loading per area unit can be achieved. This is reflected on improvements of up to 60% in terms of areal capacitance.