Magnesium‐Ion Battery Anode from Polymer‐Derived SiOC Nanobeads

Abstract

Tin‐containing silicon oxycarbide (SiOC/Sn) nanobeads are synthesized with different carbon/tin content and tested as electrodes for magnesium‐ion batteries. The synthesized ceramics are characterized by thermogravimetric‐mass spectroscopy, Fourier‐transform infrared spectroscopy, X‐ray diffraction (XRD), Raman spectroscopy, N2 sorption analysis, scanning electron microscope, energy‐dispersive X‐ray, and elemental analysis. Galvanostatic cycling tests, rate performance tests, electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) tests, and ex situ XRD measurements are conducted. Results of battery performance tests present a high capacity of 198.2 mAh g−1 after the first discharging and a reversible capacity of 144.5 mAh g−1 after 100 cycles at 500 mA g−1. Excellent rate performance efficiency of 85.2% is achieved. Battery performances in this research are influenced by surface area, and tin contentof the SiOC/Sn nanobeads. EIS, CV tests, and ex situ XRD measurements reveal that higher surface area contributes to higher capacity by providing more accessible Mg2+ ion storage sites and higher rate capability by improving the diffusion process. Higher Sn content increases battery capacity through reversible Mg‐Mg2Sn‐Mg alloying/dealloying process and improves the rate performances by increasing electrical conductivity. Besides, SiOC advances cycling stability by preventing electrode collapse and enhances the capacity due to higher surface capacitive effects.

Tin–containing Silicon Oxycarbonitride Ceramic Nanocomposites as Stable Anode for Magnesium Ion Batteries

“…The lower surface area of Sn 42.4 SiOCN nanocomposite compared with other Sn-containing SiOCN nanocomposite might be explained by the agglomeration of Sn nanoparticles (see Figure 3) that might block the pores on the sample surface. (> 0.25 V) observed in all electrodes can be assigned to the insertion of Mg 2 + ions into the micropores, defect sites, active chemical constituents, and between carbon layers of SiOCN materials, [24,30] while the plateau region between 0.15 and 0.25 V observed for only the Sn-containing electrodes could be attributed to formation of Mg 2 Sn alloy. [31,32] Irreversible reaction of Mg 2 + ions with Sn is confirmed by the difference between the de-magnesiation (C mag. )…”

“…The observations are consistent with prior studies that have examined Sn-based electrodes in the context of magnesium ion batteries. [24,51,52] Furthermore, the voltage necessary for the extraction of Mg 2 + from Mg 2 Sn exhibited a mere 0.1 V increment in positivity compared to the voltage requisite for the insertion of Mg 2 + into Sn. The observed low hysteresis indicates that the incorporation of Sn into the SiOCN ceramic matrix could potentially mitigate electrode polarization and enhance battery performance, similar to the electrochemical findings reported earlier.…”

“…The electrolyte was synthesized in a glove-box under argon following the procedure described in elsewhere. [24,28] First, 1.34 g AlCl 3 was added slowly to 40 mL THF solvent under vigorous stirring to obtain the targeted concentration. Subsequently, the acquired solution was dropwise added to a 10 mL PhMgCl/THF solution (2 M PhMgCl), followed by stirring for 16 h at room temperature.…”

“…[56][57][58][59] The formation of Mg 2 Sn is also confirmed by the shifting of the Sn 3d 5/2 peak at 483.5 eV (Figure 9b) attributed to Sn 0 in the initial anode prior to magnesiation to lower binding energy (485.3 eV) following the process of magnesiation, which corresponds to Mg 2 Sn compound. [24] The insertion of Mg ions in the SiOCN matrix is indicated by the appearance of an additional peak at 396.0 eV in the X-ray photoelectron spectra of N 1s (Figure 9c) of the anode after magnesiation, which can be assigned to NÀ Mg bond, [57,58] while only two peaks at 397.5 and 399.1 eV corresponding to the NÀ Si and NÀ C bonds, [60] respectively, are observed in the spectra of initial anode before magnesiation. Subsequently, upon demagnesiation, all the peaks corresponding to Mg bonding in the Sn/SiOCN anode disappeared, suggesting the reversibility of the electrochemical reactions between Mg and the anode materials.…”

“…[7] Although Sn/SiOC and Sn/SiCN have been applied as electrodes of rechargeable lithium ion batteries with good results in a few reports, [18][19][20][21][22] they have not been tested as an anode for magnesium ion batteries before our recently published work. [24] Our previous study showed Sn/SiOC nanobeads could be promising anode materials for magnesium ion batteries, possessing a high capacity of 198.2 mAh/g after the first discharging and a reversible capacity of 144.5 mAh/g after 100 cycles at 500 mA/g. Although our latter study showed that the battery performances were influenced by the tin content in the SiOC/Sn nanobeads, the synthesis route applied in this work did not allow us to increase the Sn and free carbon content above 6.3 wt .…”