Biomimetic branch-honeycomb carbon from crab shells: Metal oxide interface engineering for high-performance supercapacitors

We report the fabrication of biomimetic carbon materials with high electrochemical performance using simple heat treatment methods. Carbon with a branched honeycomb structure was initially synthesized from natural chitin-rich crab shells via pyrolysis, followed by a hydrothermal method to grow fruit on the carbon surface. The effects of different fruit precursors [manganese (Mn), tin (Sn), and iron (Fe) salts] on the electrochemical properties of the resulting carbon materials were investigated. The deposition of Mn oxide nanoparticles (NPs) significantly enhances the electrochemical performance of the material, while the effect of Sn oxide NPs is secondary. In contrast, Fe oxide NP deposition degrades the composite performance because they partially block the pores. Mn//700C, the optimal sample, delivers a capacitance of 179 F g −1 at a current density of 1 A g −1 . Density functional theory calculations indicate that the adsorption energy of potassium ions (the electrolyte ion) on the carbon surface supported by Mn oxide NPs is higher than that supported by other metal oxides. COMSOL simulation results further confirm that the optimal sample exhibits highly uniform potential and current density distribution, with no localized current hotspots. This study provides a cost-effective and straightforward approach to fabricate carbon-based biomimetic composites for developing high-performance supercapacitors.