Preparing two-dimensional microporous carbon from Pistachio nutshell with high areal capacitance as supercapacitor materials

Two-dimensional (2D) porous carbon AC-SPN-3 possessing of amazing high micropore volume ratio of 83% and large surface area of about 1069 m² g^-1 is high-yield obtained by pyrolysis of natural waste Pistachio nutshells with KOH activation. The AC-SPN-3 has a curved 2D lamellar morphology with the thickness of each slice about 200 nm. The porous carbon is consists of highly interconnected uniform pores with the median pore diameter of about 0.76 nm, which could potentially improve the performance by maximizing the electrode surface area accessible to the typical electrolyte ions (such as TEA ⁺, diameter ∼0.68 nm). Electrochemical analyses show that AC-SPN-3 has significantly large areal capacitance of 29.3/20.1 μF cm ^-2 and high energy density of 10/39 Wh kg^-1 at power of 52/286 kW kg^-1 in 6 M KOH aqueous electrolyte and 1 M TEABF ₄ in EC-DEC (151) organic electrolyte system, respectively.