Microporous carbon nanosheets with redox-active heteroatoms for pseudocapacitive charge storage

Abstract

We report microporous carbon nanosheets containing numerous redox active heteroatoms fabricated from exfoliated waste coffee grounds by simple heating with KOH for pseudocapacitive charge storage. We found that various heteroatom combinations in carbonaceous materials can be a redox host for lithium ion storage. The bio-inspired nanomaterials had unique characteristics, showing superior electrochemical performances as cathode for asymmetric pseudocapacitors.

3D interconnected macrostructure based on nano-scale pyroprotein units for energy storage

“…These redox-active nitrogen atoms may lead to an increase in capacity and contribute to an enhancement of electrical conductivity via N-type doping effects. 17,18,35 The 3D-IPMs prepared at a HTT of 700 °C exhibit the highest electrical conductivities of all the samples (~2.8 S cm -1 ). That this value is slightly higher than 2.5 S cm -1 supports the effect of nitrogen dopants on electrical properties [ Table 1].…”

“…[1][2][3][4][5][6][7][8][9][10][11] This bulk carbon architecture can exhibit nanometer-scale properties such as expanded surface area, which allow for nanoelectronic and nanoionic interactions within the materials' internal spaces and facilitate rapid charge storage via a pseudocapacitive mechanism. 7,12,13 Surface-driven redox reactions occur predominantly on defective carbon structures such as intrinsic topological and edge defects, as well as extrinsic defects, [14][15][16][17][18] However, sp 3 carbon structures have poor electrical conductivities, which result in unfavorable kinetic properties. In contrast, aromatic hexagonal carbon structures need additional energy to store charges on their surface [14][15][16] .…”

Waste coffee grounds-derived nanoporous carbon nanosheets for supercapacitors

“…The molecular structure of lignocellulose includes aromatic hexagonal carbon atoms that can be carbonized via relatively rapid pyrolysis [10]. Accordingly, the use of WCGs as source for carbon and activated carbon has been widely reported [11][12][13][14]. Nevertheless, there are few reports on developing nanostructured carbon-based materials from WCGs.…”

Nature‐Inspired Electrochemical Energy‐Storage Materials and Devices

“…[27] In recent years, inspirations have been taken from nature to fabricate biomolecule-based electrode materials from renewable biomass. [28][29][30][31][32] For example, inspired by the electron shuttles functioning in extracellular electron transfer via reversible redox-cycling, man-made electrode materials with similar active functional groups have been explored. [33,34] In our newly reported work, supercapacitor employing redoxactive biomolecule as the faradic-type active material could even obtain a higher energy density than those of previous transition-metal-based supercapacitors.…”