Rational design of MXene/activated carbon/polyoxometalate triple hybrid electrodes with enhanced capacitance for organic-electrolyte supercapacitors

We report a triple hybrid electrode (MXene/activated carbon (AC)/polyoxometalates (POMs)) combining the merits of three materials: MXene (high volumetric capacitance), AC (high gravimetric capacitance) and Phosphotungstate (fast redox). Phosphotungstic acid (HPW12) and tetraethylammonium phosphotung...

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Detalles Bibliográficos
Autores: Zhu, Jun-Jie|||0000-0002-8024-099X, Hemesh, Avireddy, Jacas Biendicho, Jordi|||0000-0001-5981-6168, Martinez-Soria, Luis, Rueda García, Daniel|||0000-0003-3539-1585, Morante, Joan Ramon|||0000-0002-4981-4633, Ballesteros, Belén|||0000-0002-1958-8911, Gómez-Romero, Pedro|||0000-0002-6208-5340
Tipo de recurso: artículo
Fecha de publicación:2022
País:España
Institución:Universitat Autònoma de Barcelona
Repositorio:Dipòsit Digital de Documents de la UAB
Idioma:inglés
OAI Identifier:oai:ddd.uab.cat:266356
Acceso en línea:https://ddd.uab.cat/record/266356
https://dx.doi.org/urn:doi:10.1016/j.jcis.2022.04.170
Access Level:acceso abierto
Palabra clave:Hybrid electroactive materials
MXene
Polyoxometalates
Organic
Supercapacitors
Descripción
Sumario:We report a triple hybrid electrode (MXene/activated carbon (AC)/polyoxometalates (POMs)) combining the merits of three materials: MXene (high volumetric capacitance), AC (high gravimetric capacitance) and Phosphotungstate (fast redox). Phosphotungstic acid (HPW12) and tetraethylammonium phosphotungstate (TEAPW12) were the two POMs used to prepare MXene/AC/POMs triple hybrids. MXene/AC/TEAPW12 outperformed MXene/AC/HPW12 in 1 M tetraethylammonium tetrafluoroborate (TEABF4)/acetonitrile. Nano-dispersion of POMs facilitates charge storage through surface capacitive processes (91% at 2 mV s). MXene/AC/TEAPW12 delivered significantly higher gravimetric capacitance (87F g at 1 mV s) than MXene (40F g at 1 mV s) in the same organic electrolyte, without sacrificing much volumetric capacitance (less than 10%). The gravimetric capacitance of the triple hybrid was similar to that of MXene/AC, whereas its volumetric capacitance was 1.5 times higher. Replacing TEA cations with 1-ethyl-3-methylimidazolium cations (EMIM), the capacitance improved by 21%. Coupled with AC positive electrodes in an asymmetric cell, MXene/AC/TEAPW12 delivered 4.6 times higher gravimetric energy density and 3.5 times higher volumetric energy density than a similar MXene asymmetric cell at relatively high-power densities. This study proves that MXene/AC/TEAPW12 combines the merits and compensates for the demerits of each component and is a promising electrode material for organic-electrolyte supercapacitors.

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