Beyond Surface Area: Interfacial Redox Chemistry in High-Energy-Density Hybrid Supercapacitors
- 1Nanomaterials Research Group, Department of Natural Sciences and Technology, Division of Natural Sciences, Technology and Environment, Universidad Ana G. Méndez-Gurabo Campus, Gurabo, PR 00778, USA
- 2Environmental Catalysis Research Lab, Division of Science, Technology and Environment, Cupey Campus, Universidad Ana G. Méndez, Cupey, PR 00926, USA
Abstract
High-energy-density supercapacitors are attracting increasing interest as electrochemical energy-storage devices capable of bridging the gap between conventional electric double-layer capacitors and rechargeable batteries. However, increasing energy density while preserving high power capability, long cycle life, and safety remains a major challenge. This review critically examines the role of interfacial redox chemistry and carbon/transition-metal-compound architectures in the development of high-energy-density hybrid supercapacitors. Particular attention is given to the transition from purely surface-controlled double-layer storage to pseudocapacitive and battery-type charge-storage mechanisms, emphasizing how electrode composition, nanoscale morphology, porosity, electrical conductivity, electrolyte compatibility, and interfacial stability determine practical performance. Carbonaceous materials, including activated carbons, graphene-derived structures, carbon nanotubes, and hierarchical porous carbons, are discussed as conductive and structural scaffolds for transition-metal oxides, hydroxides, sulfides, and mixed-valence compounds. The review further analyses key characterization approaches, including cyclic voltammetry, galvanostatic charge–discharge, electrochemical impedance spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and electron microscopy, highlighting how these techniques help distinguish capacitive, pseudocapacitive, and diffusion-controlled contributions. Finally, the review discusses current challenges related to mass loading, electrode density, voltage-window optimization, electrolyte selection, cycling stability, and practical device metrics. By linking interfacial chemistry, nanostructured electrode design, and realistic performance evaluation, this review aims to provide a focused framework for the rational development of high-energy-density hybrid supercapacitors.
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BibTeX
@article{martinezperales2026beyond,
title = {{Beyond Surface Area: Interfacial Redox Chemistry in High-Energy-Density Hybrid Supercapacitors}},
author = {Cristian Martínez-Perales and Abniel Machín and María C. Cotto and Francisco Díaz and José Duconge and Francisco Márquez},
journal = {Batteries},
year = {2026},
month = nov,
doi = {10.3390/batteries12110461},
url = {https://www.mdpi.com/2313-0105/12/11/461},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Beyond Surface Area: Interfacial Redox Chemistry in High-Energy-Density Hybrid Supercapacitors
AU - Cristian Martínez-Perales
AU - Abniel Machín
AU - María C. Cotto
AU - Francisco Díaz
AU - José Duconge
AU - Francisco Márquez
PY - 2026
DA - 2026/11/03
JO - Batteries
DO - 10.3390/batteries12110461
UR - https://www.mdpi.com/2313-0105/12/11/461
AB - High-energy-density supercapacitors are attracting increasing interest as electrochemical energy-storage devices capable of bridging the gap between conventional electric double-layer capacitors and rechargeable batteries. However, increasing energy density while preserving high power capability, long cycle life, and safety remains a major challenge. This review critically examines the role of interfacial redox chemistry and carbon/transition-metal-compound architectures in the development of high-energy-density hybrid supercapacitors. Particular attention is given to the transition from purely surface-controlled double-layer storage to pseudocapacitive and battery-type charge-storage mechanisms, emphasizing how electrode composition, nanoscale morphology, porosity, electrical conductivity, electrolyte compatibility, and interfacial stability determine practical performance. Carbonaceous materials, including activated carbons, graphene-derived structures, carbon nanotubes, and hierarchical porous carbons, are discussed as conductive and structural scaffolds for transition-metal oxides, hydroxides, sulfides, and mixed-valence compounds. The review further analyses key characterization approaches, including cyclic voltammetry, galvanostatic charge–discharge, electrochemical impedance spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and electron microscopy, highlighting how these techniques help distinguish capacitive, pseudocapacitive, and diffusion-controlled contributions. Finally, the review discusses current challenges related to mass loading, electrode density, voltage-window optimization, electrolyte selection, cycling stability, and practical device metrics. By linking interfacial chemistry, nanostructured electrode design, and realistic performance evaluation, this review aims to provide a focused framework for the rational development of high-energy-density hybrid supercapacitors.
SN - 2313-0105
ER -