Preparation and Performance of Porous Carbon Nanocomposite from Renewable Phenolic Resin and Halloysite Nanotube.

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 m2·g-1 with a total pore volume of 0.27 cm3·g-1. The electrochemical performance of HNT/C was characterized in the three-electrode system and showed enhanced specific capacitance of 146 F·g-1 at 0.2 A g-1 (68 F·g-1 for pristine carbon) in electrolyte (6 mol·L-1 KOH) and a good rate capability of 62% at 3 A g-1. 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-1 at a power density of 100 W·Kg-1 in 1 M Na2SO4 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.