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Hydrogenated core-shell MAX@K2Ti8O17 pseudocapacitance with ultrafast sodium storage and long-term cycling.

Zou, Guodong; Guo, Jianxin; Liu, Xianyu; Zhang, Qingrui; Huang, Gang; Fernandez, Carlos; Peng, Qiuming


Guodong Zou

Jianxin Guo

Xianyu Liu

Qingrui Zhang

Gang Huang

Qiuming Peng


Sodium-ion batteries are considered alternatives to lithium-ion batteries for energy storage devices due to their competitive cost and source abundance. However, the development of electrode materials with long-term stability and high capacity remains a great challenge. Here, this paper describes for the first time the synthesis of a new class of core-shell MAX@K2Ti8O17 by alkaline hydrothermal reaction and hydrogenation of MAX, which grants high sodium ion-intercalation pseudocapacitance. This composite electrode displays extraordinary reversible capacities of 190 mA h g-1 at 200 mA g-1 (0.9 C, theoretical value of ~219 mA h g-1) and 150 mA h g-1 at 1000 mA g-1 (4.6 C). More importantly, a reversible capacity of 75 mA h g-1 at 10 000 mA g-1 (46 C) is retained without any apparent capacity decay even after more than 10 000 cycles. Experimental tests and first-principle calculations confirm that the increase in Ti3+ on the surface layers of MAX@K2Ti8O17 by hydrogenation increases its conductivity in addition to enhancing the sodium-ion intercalation pseudocapacitive process. Furthermore, the distorted dodecahedrons between Ti and O layers not only provide abundant sites for sodium-ion accommodation but also act as wide tunnels for sodium-ion transport.


ZOU, G., GUO, J., LIU, X., ZHANG, Q., HUANG, G., FERNANDEZ, C. and PENG, Q. 2017. Hydrogenated core-shell MAX@K2Ti8O17 pseudocapacitance with ultrafast sodium storage and long-term cycling. Advanced energy materials [online], 7(18), article number 1700700. Available from:

Journal Article Type Article
Acceptance Date May 22, 2017
Online Publication Date May 22, 2017
Publication Date Sep 20, 2017
Publicly Available Date Oct 22, 2019
Journal Advanced energy materials
Print ISSN 1614-6832
Electronic ISSN 1614-6840
Publisher Wiley Open Access
Peer Reviewed Peer Reviewed
Volume 7
Issue 18
Article Number 1700700
Keywords Electrode; Hydrogenation treatment; MAX@K2Ti8O17 composite; Sodium batteries
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