Hydrolyzed Eggshell-Membrane Derived B,N,O,P-Doped 3D- Hierarchical Porous Active Carbon Electrodes for High Performance Supercapacitors

Biomass-derived activated carbon materials (BCMs) exhibit excellent supercapacitance performance with good cycling stability due to their high specific surface area and porous nature. Nevertheless, low power density (Pd) and energy density (Ed) greatly limit the practical application of BCMs. Herein, a facile three-step method was developed to fabricate 3D-hierarchical porous active carbon electrode materials (ESM-AC-CW and ESM-AC-CWA) derived from hydrolyzed eggshell membrane (H-ESM) containing multiple heteroatoms (B, N, F, P, O). ESM-AC-CWA exhibited a high surface area of 2085.10 m2/g with low weight percentage (wt%) of B, N, P, and O atoms. ESM-AC-CW showed a moderate surface area of 65.26 m2/g but with a high wt% of heteroatoms such as B, N, S, O, F, and P. Surprisingly, ESM-AC-CW and ESM-AC-CWA as electrodes display excellent electrochemical performance. In three-electrode system, ESM-AC-CWA and ESM-AC-CW exhibited excellent specific capacitance (Cs) of 582.6 F/g and 440.3 F/g, respectively, at 1 A/g. Similarly, in two-electrode system, remarkable Cs of 243.5 F/g and 159.8 F/g were achieved by ESM-AC-CWA and ESM-AC-CW, respectively. ESM-AC-CWA attained excellent cycling stability (90.8% after 10000 cycles), good Ed (18.96 Wh kg-1), maximum Pd (4818.9 W kg-1) and an excellent initial columbic efficiency of 79.1% (86.7% after 10000 cycles) at 1 A/g. To the best of our knowledge, this is the most efficient BCMs (based on Cs, Pd, and Ed) as an electrode material for supercapacitors.