TY - JOUR
T1 - Tuning MXene Properties through Cu Intercalation
T2 - Coupled Guest/Host Redox and Pseudocapacitance
AU - Wee, Shianlin
AU - Lian, Xiliang
AU - Vorobyeva, Evgeniya
AU - Tayal, Akhil
AU - Roddatis, Vladimir
AU - La Mattina, Fabio
AU - Gomez Vazquez, Dario
AU - Shpigel, Netanel
AU - Salanne, Mathieu
AU - Lukatskaya, Maria R.
N1 - Publisher Copyright:
© 2024 The Authors. Published by American Chemical Society.
PY - 2024/4/9
Y1 - 2024/4/9
N2 - MXenes are 2D transition metal carbides, nitrides, and/or carbonitrides that can be intercalated with cations through chemical or electrochemical pathways. While the insertion of alkali and alkaline earth cations into Ti3C2Tx MXenes is well studied, understanding of the intercalation of redox-active transition metal ions into MXenes and its impact on their electronic and electrochemical properties is lacking. In this work, we investigate the intercalation of Cu ions into Ti3C2Tx MXene and its effect on its electronic and electrochemical properties. Using X-ray absorption spectroscopy (XAS) and ab initio molecular dynamics (AIMD), we observe an unusual phenomenon whereby Cu2+ ions undergo partial reduction upon intercalation from the solution into the MXene. Furthermore, using in situ XAS, we reveal changes in the oxidation states of intercalated Cu ions and Ti atoms during charging. We show that the pseudocapacitive response of Cu-MXene originates from the redox of both the Cu intercalant and Ti3C2Tx host. Despite highly reducing potentials, Cu ions inside the MXene show an excellent stability against full reduction upon charging. Our findings demonstrate how electronic coupling between Cu ions and Ti3C2Tx modifies electrochemical and electronic properties of the latter, providing the framework for the rational design and utilization of transition metal intercalants for tuning the properties of MXenes for various electrochemical systems.
AB - MXenes are 2D transition metal carbides, nitrides, and/or carbonitrides that can be intercalated with cations through chemical or electrochemical pathways. While the insertion of alkali and alkaline earth cations into Ti3C2Tx MXenes is well studied, understanding of the intercalation of redox-active transition metal ions into MXenes and its impact on their electronic and electrochemical properties is lacking. In this work, we investigate the intercalation of Cu ions into Ti3C2Tx MXene and its effect on its electronic and electrochemical properties. Using X-ray absorption spectroscopy (XAS) and ab initio molecular dynamics (AIMD), we observe an unusual phenomenon whereby Cu2+ ions undergo partial reduction upon intercalation from the solution into the MXene. Furthermore, using in situ XAS, we reveal changes in the oxidation states of intercalated Cu ions and Ti atoms during charging. We show that the pseudocapacitive response of Cu-MXene originates from the redox of both the Cu intercalant and Ti3C2Tx host. Despite highly reducing potentials, Cu ions inside the MXene show an excellent stability against full reduction upon charging. Our findings demonstrate how electronic coupling between Cu ions and Ti3C2Tx modifies electrochemical and electronic properties of the latter, providing the framework for the rational design and utilization of transition metal intercalants for tuning the properties of MXenes for various electrochemical systems.
KW - 2D materials
KW - MXenes
KW - ab initio molecular dynamics
KW - charge storage mechanism
KW - in situ X-ray absorption spectroscopy
KW - pseudocapacitance
KW - transition metal intercalation
UR - http://www.scopus.com/inward/record.url?scp=85188536757&partnerID=8YFLogxK
U2 - 10.1021/acsnano.3c12989
DO - 10.1021/acsnano.3c12989
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AN - SCOPUS:85188536757
SN - 1936-0851
VL - 18
SP - 10124
EP - 10132
JO - ACS Nano
JF - ACS Nano
IS - 14
ER -