Engineering biorefinery residues from loblolly pine for supercapacitor applications

Recycling agricultural waste biomass into high-value-added products is of great importance to offset the cost of biofuel production. Here, we make biochar-based activated carbons (BACs) from loblolly pine chips via different carbonization recipes and chemical activations. BACs were then assembled into electrochemical double-layer capacitors (EDLCs) as electrode materials. Surprisingly, pyrolysis at lower temperatures (300 degrees C and 350 degrees C) rendered better electrochemical performance of BACs than those done at higher temperatures (500 degrees C and 700 degrees C). This is mainly due to the large surface area and high pore volume generated at the lower temperatures. Among all the pyrolysis recipes, flash pyrolysis at 300 degrees C produced the BAC with the highest specific capacitance (74 F g(-1) at 20 mV s(-1)), exceeding the specific capacitance of commercial activated carbon (NORIT (R)) by 45%. This report demonstrates the great potential of our refinery recipe to engineer BACs from the sustainable, affordable, and abundant natural wastes for energy-storage applications, which opens the door for a group of biorefinery residues for value-added applications. (c) 2017 Elsevier Ltd. All rights reserved.