Preparation of interconnected tin oxide nanoparticles on multi-layered MXene for lithium storage anodes

Abstract

MXenes, a novel class of two-dimensional (2D) materials known for their excellent electronic conductivity and hydrophilicity, have emerged as promising candidates for lithium-ion battery anodes. This study presents a simple wet-chemical method for depositing interconnected SnO₂ nanoparticles (NPs) onto MXene sheets. The SnO₂ NPs act as both a high-capacity energy source and a spacer to prevent MXene sheets from restacking. The highly conductive MXene facilitates rapid electron and lithium-ion transport and mitigates the volume changes of SnO₂ during the lithiation/delithiation process by confining the SnO₂ NPs between the MXene layers. This composite anode, SnO₂@MXene, leverages the high capacity of SnO₂ and the structural and mechanical stability MXene provides. The SnO₂@MXene anode exhibits superior electrochemical performance, with a high specific capacity of 678 mAh g^{- 1} at a current rate of 2.0 A g^{- 1} over 500 cycles, outperforming pristine MXenes and SnO₂ nanoparticles.

Keywords: Anode; Deposition of SnO2; Electrochemical performance; LIBs; MXene multilayers.

Fig. 1

Schematic presentation for the preparation of MXene and SnO₂@MXene nanocomposite [The diagram was created using Microsoft PowerPoint (2020 version), Available at: https://www.microsoft.com/en-us/microsoft-365/free-office-online-for-the-web]

Fig. 2

Shows (a) FE-SEM images of SnO₂ NPs and (b, c) MXene, (d–f) SnO₂@MXene, (g) elemental mapping of the hybrid SnO₂@MXene composite, and (g) SEM elemental mapping of SnO₂@MXene of Sn, O, C and Ti elements. [The surfaces were investigated using field-emission scanning electron microscopy (FE-SEM, JEOL-4001, Tokyo, Japan). Available at: https://www.jeol.com/products/scientific/sem/]

Fig. 3

(a) XRD pattern of MXene and SnO2@MXene, (b and c) HR-TEM image of MXene (Ti3C2) multi-layered structured, (d) SnO2 particles deposited on MXene, (e) selected zone (a and b) showing the d-spacing of SnO2@MXene, (f) High resolutions TEM of SnO2 and MXene, and (g) High resolution of SnO2 NPs and MXene crystallinity, (h) Selected two distinct zone of SnO2@MXene, (i) schematic diagram of SnO2 NPs and MXene layers and (j) elemental mapping of the SnO2@MXene sample. [High-resolution transmission electron microscopy (HR-TEM, JEOL JEM-2000), scanning TEM (STEM), Tokyo, Japan. Available at: https://www.jeol.com/products/scientific/tem/JEM-2100.php]

Fig. 4

(a) Raman spectra of MXene (Ti₃C₂), SnO₂, and SnO₂@MXene, (b) surface areas of SnO₂ and SnO₂@MXene nanocomposites, (c) XPS spectra of SnO₂@MXene, and (d–f) XPS spectra of Ti, Sn, and C, of hybrid SnO₂@ MXene.

Fig. 5

(a) CV of SnO₂@MXene first three cycles, (b) charging /discharging profile of Ti₃C₂, SnO₂, and SnO₂@MXene, (c) cycling performance of three samples for comparison, (d) discharge–charge profile of SnO₂@MXene (500 cycles), (e) different current rate performance of MXene and SnO₂@MXene, (f) EIS Nyquist plots of MXene, SnO₂, and SnO₂@MXene, (g) long cycling performance of SnO₂@MXene, and (h) schematic diagram of rapid electron and Li-ion transportation.

Fig. 6

(a–c) SEM images of SnO₂@MXene nanocomposite after cycling, (d-f) high-resolution TEM images of SnO₂@MXene after 100 cycles.