Hybrid Charge‐Storage Route to Nb₂CT_xMXene as Anode for Sodium‐Ion Batteries

Abstract

A facile hydrothermal approach has been successfully adopted to synthesize two-dimensional Nb 2 CT x MXene, targeting sodium storage approach in two-dimensional MXene. As an anode material for sodium-ion batteries (SIBs), as-prepared Nb 2 CT x MXene delivered a stable electrochemical performance of ∼ 102 mA h g À 1 after 500 cycles at a current density of 1.0 A g À 1 . Further, the full cell comprising of Na 3 V 2 (PO 4 ) 3 @C cathode and Nb 2 CT x MXene anode also rendered a reversible capacity of 181 mA h g À 1 at a current density of 100 mA g À 1 after 50 cycles. The good sodium storage could be ascribed to the contribution of hybrid pseudocapacitance, effectively promoted charge storage, unique layered structure and expedited dynamic diffusion of ions. Accordingly, these facts enabled the Nb 2 CT x MXene to be a promising candidate as an anode material for sodium-ion batteries. Results and DiscussionHere, a facile hydrothermal route was chosen to synthesize Nb 2 CT x MXene, with an advantage of environmentally friendly and efficient stripping. In addtion, it was conducive to the generation of high valence of Nb. X-ray diffraction (XRD) profiles of Nb 2 AlC before and after HF etching were showed in [a] Dr.

MXene‐Based Materials for Electrochemical Sodium‐Ion Storage

“…synthesized Nb 2 CT x /Nb 2 O 5 composites by mild hydrothermal approach, in which MXenes are partially oxidized to Nb 2 O 5 in the process. [ 128 ] Thanks to the hybrid pseudocapacitance including the surface‐controlled pseudocapacitance and intercalation pseudocapacitance at the high and low potential, respectively, the composite rendered a capacity of 102 mAh g −1 at 1 A g −1 after 500 cycles for SIBs.…”

“…Du et al synthesized Nb 2 CT x /Nb 2 O 5 composites by mild hydrothermal approach, in which MXenes are partially oxidized to Nb 2 O 5 in the process. [128] Thanks to the hybrid pseudocapacitance including the surface-controlled pseudocapacitance [126] Copyright 2018, Elsevier Ltd. b) Rate capability of MXene@NTP-C and MXene at varied current densities of 0.1-10 A g −1 . Reproduced with permission.…”

Interlayer Engineering Construction of 2D Nb2CTx with Enlarged Interlayer Spacing Towards High Capacity and Rate Capability for Lithium‐Ion Storage

“…The other two peaks (Nb−O and Nb(V)−O) located at 205.1 eV and 207.6 eV are related to Nb 2 O 5 , which is attributed to the adsorption of oxygen elements on the surface. The spectrum of N 1s at 393.0 eV, 397.8 eV, and 399.9 eV corresponding to N−C, N−H, and −NH 2 bonds of PPDA‐Nb 2 CT x [38] (Figure 1g). Besides, the C 1s and Nb 3d spectra of Nb 2 CT x are similar with that of PPDA‐Nb 2 CT x as shown in Figure S1, suggesting the intercalation of PPDA molecules has no effect on the chemical state of Nb 2 CT x .…”

Recent status and challenges in multifunctional electrocatalysis based on 2D MXenes

“…55 The efficient etching method was investigated for Ti 2 N (MXene), synthesized by selective etching of Al from a Ti 2 AlN precursor using a potassium fluoride and hydrochloric acid combination. 56,57 In another study, ammonization at 600 °C transforms Mo 2 CT x and V 2 CT x carbide MXenes into 2D metal nitrides. Mo 2 N maintains the MXene structure while V 2 N changes into a mixed layer structure, including trigonal V 2 N and cubic VN.…”