Meso-pore dominant activated carbon from spent coffee grounds for high-performance electrochemical capacitors in organic electrolyte

Porous Carbon Nanosheets Derived from Spent Coffee Grounds for Highly Stable Electric Double-Layer Capacitors Enabled by Structurally Complementary Carbons

“…Clearly, the appropriate proportion of BP2000/Super P = 75/25 in AC2500 is superior to that of all other carbon samples. The specific capacitance of an AC2500-based electrode can reach 224.6 F g –1 at 0.5 A g –1 , which is higher than that of previously reported organic EDLC systems. − …”

“…Recently, new-concept porous materials paired with appropriate electrolytes have demonstrated significant improvements in energy density for EDLC. , Hierarchical porous carbons with an appropriate micropore/mesopore proportion appear to have a greater specific capacitance as well as a high energy density. − Even so, designing the optimum pore shape for ions diffusion and a high connecting framework for electron transportation in carbon-based materials remains a challenge, particularly in quick charge–discharge behaviors. − Porous nanosheet-like morphologies, such as graphene or graphene-based components, ,,, have showed remarkable energy density with high power density among the superior forms of known carbon materials. Aside from graphene-based materials, a simple and cost-effective approach based on similar nanosheet-like structures generated from biomass wastes may also be beneficial for high-performance EDLC. − As we know, only a few biomass wastes, such as SCGs, can generate 2D PCNs structures. − However, under fast charge–discharge conditions, the specific capacitance clearly decayed due to a lack of high electron-connecting channels, which will slow the electrolyte ions’ access to the surface of the carbon electrodes. This disadvantage was partially overcome by the addition of an electron conductive additive, such as CB Super P, acetylene, or BP2000, to create effective electron-transporting pathways anchored on porous carbons.…”

“…The preparation process is illustrated in Scheme . A more detailed procedure was described in our previous report . The benefit of this process is that it is eco-friendly, low-cost, and sustainable due to the abundance of biomass waste around the world .…”

“…A more detailed procedure was described in our previous report. 30 The benefit of this process is that it is eco-friendly, low-cost, and sustainable due to the abundance of biomass waste around the world. 33 The as-prepared sample is designated as AC1200, where the number (1200) represents the approximate specific surface area determined by the Brunauer−Emmett−Teller (BET) method.…”

“…Yu et al proposed a model to generate desired thickness and pore structures of 2D PCNs with fast ion transport for high-energy-density supercapacitors . Several significant accomplishments have recently been completed using SCGs as precursors to yield 2D PCNs as the crucial electrode material for supercapacitors. − Most recently, a review article thoroughly described the recent advances and future opportunity for reusing SCGs as electrode materials for energy storage devices . These studies demonstrate a clear vision for converting SCGs into high-value materials with the potential for mass production.…”