One-step synthesis of few-layer niobium carbide MXene as a promising anode material for high-rate lithium ion batteries.

Two-dimensional (2D) few-layer MXene nanosheets have attracted extensive attention due to their great potential for high-rate energy storage devices, but a simplified method to synthesize these structures with good cycling and rate performances is still a challenge for the MXene family. In this work, a one-step method to synthesize 2D few-layer niobium carbide (Nb2CTx) MXene nanosheets by etching Nb2AlC powder is reported for the first time. A sample of the few-layer Nb2CTx electrode shows a high specific capacity of 354 mA h g-1 at 0.05 A g-1 with a long cycling lifetime. The specific capacity can be stabilized at 225 mA h g-1 after 800 cycles at 1.0 A g-1. The one-step synthesis of unassisted few-layer Nb2CTx MXene nanosheets paves the way for the exploration of Nb2CTx-based composite materials and applications.