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Title: Understanding the MXene Pseudocapacitance

Journal Article · · Journal of Physical Chemistry Letters

MXenes have attracted great attention as next-generation capacitive energy-storage materials, but the mechanisms underlying their pseudocapacitive behavior are not well understood. Here we provide a theoretical description of the surface redox process of Ti3C2Tx (T = O, OH), a prototypical MXene, in 1 M H2SO4 electrolyte, based on joint density functional theory with an implicit solvation model and the analysis of Gibbs free energy under a constant-electrode potential. From the dependence of the O/OH ratio (or the surface H coverage) and the surface charge on the applied potential, we obtain a clear picture of the capacitive energy-storage mechanism of Ti3C2Tx that shows good agreement with previous experimental findings in terms of the integral capacitance and Ti valence change. We find a voltage-dependent redox/double-layer co-charging behavior: the capacitive mechanism is dominated by the redox process, but the electric double-layer charge works against the redox process. This new insight may be useful in improving the capacitance of MXenes.

Research Organization:
Energy Frontier Research Centers (EFRC) (United States). Fluid Interface Reactions, Structures and Transport Center (FIRST); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
AC05-00OR22725; AC02-05CH11231
OSTI ID:
1493989
Alternate ID(s):
OSTI ID: 1484259
Journal Information:
Journal of Physical Chemistry Letters, Vol. 9, Issue 6; ISSN 1948-7185
Publisher:
American Chemical SocietyCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 197 works
Citation information provided by
Web of Science

References (37)

Role of Surface Structure on Li-Ion Energy Storage Capacity of Two-Dimensional Transition-Metal Carbides journal April 2014
Cation Intercalation and High Volumetric Capacitance of Two-Dimensional Titanium Carbide journal September 2013
Ion Intercalation into Two-Dimensional Transition-Metal Carbides: Global Screening for New High-Capacity Battery Materials journal October 2014
MXene-based materials for electrochemical energy storage journal January 2018
MXene: a promising transition metal carbide anode for lithium-ion batteries journal March 2012
Sulfur Cathodes Based on Conductive MXene Nanosheets for High-Performance Lithium-Sulfur Batteries journal February 2015
Are MXenes Promising Anode Materials for Li Ion Batteries? Computational Studies on Electronic Properties and Li Storage Capability of Ti 3 C 2 and Ti 3 C 2 X 2 (X = F, OH) Monolayer journal September 2012
Two-Dimensional Molybdenum Carbide (MXene) as an Efficient Electrocatalyst for Hydrogen Evolution journal August 2016
Electrochemical and in-situ X-ray diffraction studies of Ti 3 C 2 T x MXene in ionic liquid electrolyte journal November 2016
Effect of Postetch Annealing Gas Composition on the Structural and Electrochemical Properties of Ti 2 CT x MXene Electrodes for Supercapacitor Applications journal July 2015
Flexible and conductive MXene films and nanocomposites with high capacitance journal November 2014
Solving the Capacitive Paradox of 2D MXene using Electrochemical Quartz-Crystal Admittance and In Situ Electronic Conductance Measurements journal August 2014
High-Capacitance Mechanism for Ti 3 C 2 T x MXene by in Situ Electrochemical Raman Spectroscopy Investigation journal November 2016
Probing the Mechanism of High Capacitance in 2D Titanium Carbide Using In Situ X-Ray Absorption Spectroscopy journal May 2015
Ultra-high-rate pseudocapacitive energy storage in two-dimensional transition metal carbides journal July 2017
Atomic Defects in Monolayer Titanium Carbide (Ti 3 C 2 T x ) MXene journal September 2016
Nanoscale Elastic Changes in 2D Ti 3 C 2 T x (MXene) Pseudocapacitive Electrodes journal March 2016
NMR reveals the surface functionalisation of Ti 3 C 2 MXene journal January 2016
Probing the electrochemical capacitance of MXene nanosheets for high-performance pseudocapacitors journal January 2016
Atomic-Scale Analysis of the RuO 2 /Water Interface under Electrochemical Conditions journal April 2016
Ab Initio Study of the Charge-Storage Mechanisms in RuO 2 -Based Electrochemical Ultracapacitors journal December 2011
Charge Storage Mechanism of RuO 2 /Water Interfaces journal August 2017
Understanding the pseudocapacitance of RuO 2 from joint density functional theory journal September 2016
Impacts of electrode potentials and solvents on the electroreduction of CO 2 : a comparison of theoretical approaches journal January 2015
Atomistic Mechanisms Underlying Selectivities in C 1 and C 2 Products from Electrochemical Reduction of CO on Cu(111) journal December 2016
Joint Density-Functional Theory:  Ab Initio Study of Cr 2 O 3 Surface Chemistry in Solution journal August 2005
Joint density-functional theory for electronic structure of solvated systems journal May 2007
Grand canonical electronic density-functional theory: Algorithms and applications to electrochemistry journal March 2017
Joint density functional theory of the electrode-electrolyte interface: Application to fixed electrode potentials, interfacial capacitances, and potentials of zero charge journal August 2012
The importance of nonlinear fluid response in joint density-functional theory studies of battery systems journal October 2013
The charge-asymmetric nonlocally determined local-electric (CANDLE) solvation model journal February 2015
Generalized Gradient Approximation Made Simple journal October 1996
Pseudopotentials for high-throughput DFT calculations journal January 2014
Dependence of elastic and optical properties on surface terminated groups in two-dimensional MXene monolayers: a first-principles study journal January 2016
Conductive two-dimensional titanium carbide ‘clay’ with high volumetric capacitance journal November 2014
A grid-based Bader analysis algorithm without lattice bias journal January 2009
Accurate and efficient algorithm for Bader charge integration journal February 2011

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MXene-Conducting Polymer Asymmetric Pseudocapacitors journal December 2018
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Delaminating Vanadium Carbides for Zinc‐Ion Storage: Hydrate Precipitation and H + /Zn 2+ Co‐Action Mechanism journal August 2019
Layer-by-layer self-assembly of pillared two-dimensional multilayers journal June 2019
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Figures / Tables (6)