High Energy Density Asymmetric Aqueous Supercapacitor Based on a 2D Manganese Carbide as a Positive Electrode
Year: 2025
Type: article
Abstract: ABSTRACT Maximizing the energy density of aqueous supercapacitors based on MXenes remains a critical challenge due to narrow voltage windows, sluggish or irreversible redox reactions, particularly at extreme and positive potentials. Here, we report a previously unexplored etched manganese–aluminum carbide (EMAX) synthesized via a circular route from waste surgical masks, delivering sustainability alongside performance. EMAX features improved porosity, low work function (2 eV), and a layered architecture with rough surface, while encoding Mn 4+ /Mn 2+ redox sites that underpin fast and reversible pseudocapacitance. In a three–electrode configuration, EMAX achieves superior gravimetric (975 F g −1 ) and volumetric (1657 F cm −3 ) capacitances. Its intrinsically low work function enables favorable electrode potential alignment (avoiding irreversible anodic oxidation) and effective operation in acidic aqueous electrolytes at extended positive potentials. Consequently, when paired with high‐work‐function nitrogen‐doped graphene, the asymmetric device operates particularly efficiently at 1.6 V, reaching a specific energy of 125.5 Wh kg −1 and 213 Wh L −1 and at a specific power of 863 W L −1 , previously considered unachievable in aqueous electrolyte devices. Together, these results highlight work function engineering, coupled with sustainable carbide synthesis, fast and reversible Mn redox sites, and etching‐induced nano‐architecture, leading to a substantial performance advancement in aqueous asymmetric supercapacitors.
Source: Advanced Functional Materials
Language: English
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $5,790
Funders: European Commission, Ministerstvo Školství, Mládeže a Tělovýchovy, Grantová Agentura České Republiky, Ministerstvo Životního Prostředí, HORIZON EUROPE Framework Programme, European Regional Development Fund, European Social Fund, H2020 Marie Skłodowska-Curie Actions, HORIZON EUROPE European Innovation Council
Awards: G1153767801, G1492781007, TWINNING EXCELLENCE IN MANAGEMENT AND RESEARCH FOR GREEN ENERGY AND CHEMICALS USING SINGLE-ATOM CATALYSIS, G164752657, G1694346177, G2677629327, G2678520069, G2685858526, G2778226874, G291036901, G3298089404, G3735356012, G3771185154, G3810236772, Graphene acid heterostructures with MXenes for lithium and sodium ion batteries, G4396925471, G5162580495, G5295502948, G6253592498, G6666489062, G6763527096, Transition of 2D-chemistry based supercapacitor electrode material from proof of concept to applications, Nanomaterials and Nanotechnologies for Environment Protection and Sustainable Future
OpenAlex ID: W4417493393