Nitrogen-doped Nb2CTx MXene as anode materials for lithium ion batteries.

MXene, a recently discovered family of 2D materials, is well known for its application in energy storage areas due to its excellent properties. However, the low capacity of pristine MXene limits its application in energy storage devices such as lithium ion batteries. To solve this problem, we synthesized a new type of N-doped two-dimensional Nb 2 CT x MXene. The nitrogen content of N-doped MXene was 4.5 at% after thermal reaction with urea. The introduction of nitrogen into MXene nanosheets increases c-lattice parameter of Nb 2 CT x MXene from 22.32 Å to 34.78 Å. And the incorporation of nitrogen into MXene nanosheets leads to superior electrochemical performance. For example, the N-doped Nb 2 CT x shows an increased reversible capacity of 360 mAh /g at 0.2C, which is much higher than that of the un-doped Nb 2 CT x MXene (190 mAh/g at 0.2C). And the N-doped Nb 2 CT x MXene also shows excellent cycling stability (288 mAh/g at 0.5C after 1500 cycles). Our results suggest N-doped Nb 2 CT x MXene is promising for energy storage applications. Image 1 • Nitrogen doped Nb 2 CT x MXene is firstly prepared through hydrothermal reaction. • N-doping leads to increased intersheet distance and larger specific surface area. • N-doping leads to a 90% increase of capacity at 0.2C. • The N Nb 2 CT x anode shows a high level of capacity retention (92% after 1500 cycles at 0.5C). [ABSTRACT FROM AUTHOR]