Authors: Adnane Bouzina, René Meng, Cyrille Bazin, Hubert Perrot, Ozlem Sel, Catherine Debiemme-Chouvy

Journal: Adv. Mater. Interfaces (2023)

Abstract

The simple and eco-friendly preparation of microsupercapacitor remains a great challenge. Here are presented the preparation and the characterizations of an all-solid symmetric micro-supercapacitor based on a new composite formed of highly ordered graphene sheets due to the presence of polydopamine between the layers, which present a d-spacing of 0.356 nm. This graphene-polydopamine composite is prepared by electroreduction of graphene oxide (GO) followed by the electrooxidation of dopamine added into the initial solution, i.e., after GO reduction. In Na₂SO₄ solution, this composite material shows excellent capacitance and stability even at a high scan rate (2 V s⁻¹) and a very low relaxation time (τ₀) of 62 ms. This value is in very good agreement with the high transfer kinetic and low transfer resistance values of the ions implied in the charge storage process (Na⁺·2H₂O and Na⁺) determined by ac-electrogravimetry. Finally, it is shown that the all-solid micro-supercapacitor (interdigitated electrodes obtained using a CO₂ laser and Na₂SO₄/PVA hydrogel) prepared with this new composite delivers a remarkable energy density of 6.36 mWh cm⁻³ for a power density of 0.22 W cm⁻³ and exhibits excellent cycling stability (98% of retention after 10 000 cycles at 2 V s⁻¹).

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