Towards high-energy-density supercapacitors via less-defects activated carbon from sawdust

Increasing the specific energy of the supercapacitor is vital for utilization in both energy and power intensive operations. In this study, the operating voltage and specific energy of the supercapacitor were extended by utilizing modified activated carbon with less defects. The activated carbon was produced from sawdust via a non-destructive activation (NDA) process using potassium hydroxide (KOH) as activation agent and aluminium (Al) as additive. A reference sample without additive was compared to the modified activated carbon produced with varying additive intensity. High specific surface area, increased micropore volumes, decreased mesopore volumes and reduced defects were observed in one of the NDA samples. Furthermore, superior electrochemical performance was achieved with a specific capacitance of 160 F g(-1) and operating voltage window extended to 3 V in conventional organic electrolyte. As a result, the specific energy was boosted to 49 Wh kg(-1) based on the mass of activated carbon. The NDA carbon assembled cells also exhibited a high cyclic stability with 97% capacity retention after 5000 cycles. (C) 2020 Elsevier Ltd. All rights reserved.