Unraveling the Charge Storage Mechanism of Ti3C2Tx MXene Electrode in Acidic Electrolyte

Hui Shao (1, 2) , Kui Xu , Yih-Chyng Wu (1, 2) , Antonella Iadecola (2) , Liyuan Liu (1, 2) , Hongyun Ma (3) , Liangti Qu (3) , Encarnación Raymundo-Piñero (4, 2) , Jixin Zhu , Zifeng Lin (5) , Pierre-Louis Taberna (1, 2) , Patrice Simon (1, 2, 6)

1 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux
2 RS2E - Réseau sur le stockage électrochimique de l'énergie
3 THU - Tsinghua University [Beijing]
4 CEMHTI - Conditions Extrêmes et Matériaux : Haute Température et Irradiation
5 SCU - Sichuan University [Chengdu]
6 IUF - Institut universitaire de France

Two-dimensional Ti3C2Tx MXenes have been extensively studied as pseudocapacitive electrode materials. This Letter aims at providing further insights into the charge storage mechanism of the Ti3C2Tx MXene electrode in the acidic electrolyte by combining experimental and simulation approaches. Our results show that the presence of H2O molecules between the MXene layers plays a critical role in the pseudocapacitive behavior, providing a pathway for proton transport to activate the redox reaction of the Ti atoms. Also, thermal annealing of the samples at different temperatures suggests that the presence of the confined H2O molecules is mainly controlled by the surface termination groups. These findings pave the way for alternative strategies to enhance the high-rate performance of MXenes electrodes by optimizing their surface termination groups.

Mots clés: Layers; Molecules; Two dimensional materials; Electrodes; Electrolytes

Domaines: Matériaux; Autre

Hui Shao, Kui Xu, Yih-Chyng Wu, Antonella Iadecola, Liyuan Liu, et al.. Unraveling the Charge Storage Mechanism of Ti3C2Tx MXene Electrode in Acidic Electrolyte. ACS Energy Letters, 2020, 5 (9), pp.2873-2880. ⟨10.1021/acsenergylett.0c01290⟩. ⟨hal-03065967⟩