Chitin -a naturally occurring biopolymer -was employed for the first time as binder of carbon electrodes and studied in electrochemical capacitor. Chitinbound electrodes have shown excellent performance in neutral aqueous electrolyte up to 5 A g -1 current load with capacitance retention of ca. 80% of initial value for mild regimes. This manuscript reports on the electrochemical behaviour of commercially available activated carbon (Supra 30 NORIT) bound with chitin (10% wt.) in the form of pellets, operating in two different aqueous electrolytes, i.e. 1M Li 2 SO 4 and 1M KI solutions. It has been found that, for the 1M Li 2 SO 4 solution, the carbon electrodes demonstrate moderate capacitance value of 65 F g -1 at 1 A g -1 current density. In 1M KI solution merging electrical double-layer capacitance and faradaic contribution of the iodide/iodine redox couple, at the same current load, the capacitance was of 175 F g -1 and it significantly increased with cycling to 260 F g -1 in case of the chitin binder, and 300 F g -1 for the PTFE-bound electrodes taking into account the total charge supplied during capacitor discharging. Moreover, for the 1M Li 2 SO 4 solution, the chitin-bound electrodes display slightly better charge propagation than the PTFEbound ones, whereas for the 1M KI solution, the energy of the capacitor has been improved by 1 Wh kg -1 . Considering the rather negative impact of the commonly used binding fluoropolymers on the environment, chitin may become a great alternative for development of cheap and environmentally benign 2 electrochemical capacitors, while preserving their mechanical and electrochemical performance. Additionally, fluorine-based (e.g. PVdF or PTFE) electrodes are more hydrophobic and thus electrolyte penetration into the bulk of electrodes is unfavoured. Noteworthy, the formation of a chitin complex with electrochemically generated iodine, which has a tendency to leave the system, may enhance the reversibility of the iodide/iodine redox couple and improve both the capacitance value as well as the cycle life. 11 negligible difference in pore-blocking when compared to PTFE-bound electrode.This suggest that -similarly to PTFE -chitin has an impact on the specific surface area, but there is still a significant part of microporosity accessible for ions from electrolyte solution. Fig. 3. (A) Nitrogen sorption isotherms of Supra 30, PTFE-bound electrode, and chitin-bound electrode (B) pore size distribution of materials estimated by 2D-NDLFTAs mentioned before, the application of chitin as a binder could be an interesting approach to develop environmentally-friendly and safe 18 formation 39 ; this complex may trap the iodine in the chitin structure according to mechanism already deeply investigated and presented in Fig. 8, and enhance the cyclability by reversible redox reaction of iodine to (poly)iodides.On the other hand, if to consider only the slope of discharge profile, i.e. pure electrostatic attraction, the capacitance value remains stable, at the level of 160 F g -1 .