MXene: a promising transition metal carbide anode for lithium-ion batteries

Herein we report on Li insertion into a new two-dimensional (2-D) layered Ti2C-based material (MXene) with an oxidized surface, formed by etching Al from Ti2AlC in HF at room temperature. Nitrogen sorption of treated powders showed desorption hysteresis consistent with the presence of slit-like pores. At 23 m(2) g(-1), the specific surface area was an order of magnitude higher than untreated Ti2AlC. Cyclic voltammetry exhibited lithiation and delithiation peaks at 1.6 V and 2 V vs. Li+/Li, respectively. At C/25, the steady state capacity was 225 mAh g(-1); at 1C, it was 110 mAh g(-1) after 80 cycles; at 3C, it was 80 mAh g(-1) after 120 cycles: at 10C, it was 70 mAh g(-1) after 200 cycles. Since Ti2C is a member of the MXene family - where M is an early transition metal and X is C and/or N - that to date includes Ti3C2,Ta4C3,TiNbC, and (V-0.5,Cr-0.5)(3)C-2, our results suggest that MXenes are promising as anode materials for Li-ion batteries. (C) 2012 Elsevier B.V. All rights reserved.