| Summary: | The growing demand for high performance from supercapacitors has inspired the development of porous nanocomposites using renewable and naturally available materials. In this work, a formaldehyde-free phenolic resin using monosaccharide-based furfural was synthesized to act as the carbon precursor. One dimensional halloysite nanotube (HNT) with high porosity and excellent cation/anion exchange capacity was mixed with the phenol-furfural resin to fabricate carbonaceous nanocomposite HNT/C. Their structure and porosity were characterized. The effects of the halloysite nanotube amount and carbonization temperature on the electrochemical properties of HNT/C were explored. HNT/C exhibited rich porosity, involving a large specific surface area 253 m<sup>2</sup>·g<sup>−1</sup> with a total pore volume of 0.27 cm<sup>3</sup>·g<sup>−1</sup>. The electrochemical performance of HNT/C was characterized in the three-electrode system and showed enhanced specific capacitance of 146 F·g<sup>−1</sup> at 0.2 A g<sup>−1</sup> (68 F·g<sup>−1</sup> for pristine carbon) in electrolyte (6 mol·L<sup>−1</sup> KOH) and a good rate capability of 62% at 3 A g<sup>−1</sup>. It also displayed excellent cycle performance with capacitance retention of 98.5% after 500 cycles. The symmetric supercapacitors with HNT/C-1:1.5-800 electrodes were fabricated, exhibiting a high energy density of 20.28 Wh·Kg<sup>−1</sup> at a power density of 100 W·Kg<sup>−1</sup> in 1 M Na<sub>2</sub>SO<sub>4</sub> electrolyte. The present work provides a feasible method for preparing composite electrode materials with a porous structure from renewable phenol-furfural resin and HNT. The excellent supercapacitance highlights the potential applications of HNT/C in energy storage.
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