Exploring Shrimp Shell Powder as a Bio-Template for the Synthesis of Hierarchical Porous Biocarbon From Lignin for Supercapacitor Applications

Sodium lignosulfonate was effectively converted into hierarchical porous biocarbon (L/SS-PC) by employing shrimp shell as a bio-template. Further, its properties were enhanced by using KOH as a chemical activating agent (L/SS-AC). To understand the effect of the bio-template and activating agent, sodium lignosulfonate was converted into pristine (L-PC) and activated (L-AC) biocarbon materials by adopting similar processing conditions of 600°C for 1 h under an N₂ atmosphere. The prepared samples are subjected to various characterizations such as CHNS, X-ray diffraction, Fourier transform infrared spectroscopy, Raman, scanning electron microscopy–EDX analysis, and BET surface area analysis to identify their structural and morphological features. The specific surface area of synthesized biocarbon materials is found to be 86, 176, 88, and 836 m² g⁻¹, respectively for the L-PC, L-AC, L/SS-PC, and L/SS-AC. The synthesized biocarbons were used as electrode materials to fabricate the symmetric supercapacitor employing a pouch cell assembly using 1 M KOH as the electrolyte. Their specific capacitance was calculated to be 8.68, 36.56, 18.74, and 72.0 F g⁻¹ at 0.5 A g⁻¹, respectively, for L-PC, L-AC, L/SS-PC, and L/SS-AC biocarbons. The energy density and power density of the activated hierarchical porous biocarbon (L/SS-AC) were 2.452 Wh kg⁻¹ and 247.67 W kg⁻¹ at 0.5 A g⁻¹.