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Pillared Mo2TiC2 MXene for High-Power and Long-life Lithium and Sodium-ion Batteries

preprint
revised on 11.01.2021, 14:33 and posted on 12.01.2021, 07:11 by Philip A. Maughan, Luc Bouscarrat, Valerie R. Seymour, Shouqi Shao, Sarah J Haigh, Richard Dawson, Nuria Tapia-Ruiz, Nuno Bimbo

In this work, we apply an amine-assisted silica pillaring method to create the first example of a porous Mo2TiC2 MXene with nanoengineered interlayer distances. The pillared Mo2TiC2 has a surface area of 202 m2 g-1, which is among the highest reported for any MXene, and has a variable gallery height between 0.7 and 3 nm. The expanded interlayer distance leads to significantly enhanced cycling performance for Li-ion storage, with superior capacities, rate capabilities and cycling stabilities in comparison to the non-pillared version. The pillared Mo2TiC2 achieved capacities over 1.7 times greater than multilayered MXene at 20 mA g-1 (≈ 320 mAh g-1) and 2.5 times higher at 1 A g-1 (≈ 150 mAh g-1). The fast-charging properties of pillared Mo2TiC2 are further demonstrated by outstanding stability even at 1 A g-1 (under 8 min charge time), retaining 80% of the initial capacity after 500 cycles. Furthermore, we use a combination of spectroscopic techniques (i.e. XPS, NMR and Raman) to show unambiguously that the charge storage mechanism of this MXene occurs by a conversion reaction through the formation of Li2O. This reaction increases by 2-fold the capacity beyond intercalation, and therefore, its understanding is crucial for further development of this family of materials. In addition, we also investigate for the first time the sodium storage properties of the pillared and non-pillared Mo2TiC2.


Funding

EPSRC Graphene NOWNANO Centre for Doctoral Training

Royal Society (RG170150)

EPSRC EP/R00661X/1

EPSRC EP/S019367/1

EPSRC EP/P025021/1

EPSRC EP/P025498/1

EPSRC EP/P009050/1

European Research Council Horizon 2020 Starter Grant EvoluTEM (715502)

History

Email Address of Submitting Author

n.bimbo@soton.ac.uk

Institution

University of Southampton

Country

United Kingdom

ORCID For Submitting Author

0000-0001-8740-8284

Declaration of Conflict of Interest

N/A

Version Notes

Version 1 - June 2020 Version 2 - January 2021 - inclusion of STEM results and Shouqi Shao and Prof Haigh as authors. Slight change of title and further modifications to the previous draft.

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