TY - JOUR
T1 - MXene Electrode Materials for Electrochemical Energy Storage
T2 - First-Principles and Grand Canonical Monte Carlo Simulations
AU - Okada, Yasuaki
AU - Keilbart, Nathan
AU - Goff, James M.
AU - Higai, Shin'ichi
AU - Shiratsuyu, Kosuke
AU - Dabo, Ismaila
N1 - Publisher Copyright:
© Materials Research Society 2019.
PY - 2019
Y1 - 2019
N2 - MXenes are a novel class of two dimensional materials, discovered by Barsoum and Gogotsi [M. Naguib, J. Come, B. Dyatkin, V. Presser, P. Taberna, P. Simon, M. W. Barsoum, and Y. Gogotsi, Electrochemistry Communications 16, 61-64 (2012); B. Anasori, M. R. Lukatskaya, and Y. Gogotsi, Nature Reviews Materials vol. 2, 16098 (2017)]. Their large specific surface area and the tunability of their physicochemical properties as a function of the transition metal and surface terminal group make them a unique design platform for various applications, a primary example of which is pseudocapacitive energy storage. However, there is still incomplete understanding of how the transition metal chemistry and stoichiometry, and the surface termination affect charge storage mechanisms in MXene. In this study, we have performed systematic first-principles calculations for bulk MXene and found that the atomic charge of the metal cations, which is related to their valence, decreases across the d-electron metal series. Electronic-structure indicators of performance are examined to understand the energy storage behavior, whereby charges are stored between the terminal groups and adsorbing cations. Importantly, we found that the differential Bader charges show good agreement with theoretical capacitances and are useful in predicting charge storage trends in MXene-based pseudocapacitors. Furthermore, we have performed first-principles and grand canonical Monte Carlo calculations for the slab systems, finding that the solvent plays a critical role in enhancing the pseudocapacitive response.
AB - MXenes are a novel class of two dimensional materials, discovered by Barsoum and Gogotsi [M. Naguib, J. Come, B. Dyatkin, V. Presser, P. Taberna, P. Simon, M. W. Barsoum, and Y. Gogotsi, Electrochemistry Communications 16, 61-64 (2012); B. Anasori, M. R. Lukatskaya, and Y. Gogotsi, Nature Reviews Materials vol. 2, 16098 (2017)]. Their large specific surface area and the tunability of their physicochemical properties as a function of the transition metal and surface terminal group make them a unique design platform for various applications, a primary example of which is pseudocapacitive energy storage. However, there is still incomplete understanding of how the transition metal chemistry and stoichiometry, and the surface termination affect charge storage mechanisms in MXene. In this study, we have performed systematic first-principles calculations for bulk MXene and found that the atomic charge of the metal cations, which is related to their valence, decreases across the d-electron metal series. Electronic-structure indicators of performance are examined to understand the energy storage behavior, whereby charges are stored between the terminal groups and adsorbing cations. Importantly, we found that the differential Bader charges show good agreement with theoretical capacitances and are useful in predicting charge storage trends in MXene-based pseudocapacitors. Furthermore, we have performed first-principles and grand canonical Monte Carlo calculations for the slab systems, finding that the solvent plays a critical role in enhancing the pseudocapacitive response.
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U2 - 10.1557/adv.2019.292
DO - 10.1557/adv.2019.292
M3 - Article
AN - SCOPUS:85085660648
SN - 2059-8521
VL - 4
SP - 1833
EP - 1841
JO - MRS Advances
JF - MRS Advances
IS - 33-34
ER -