High throughput production of nanocomposite SiO_x powders by plasma spray physical vapor deposition for negative electrode of lithium ion batteries

Figures & data

Figure 1 Calculated equilibrium chemistries in the (a) Ar–H–O–Si and (b) Ar–H–O–Si–C system under the conditions equivalent to the experiment shown in table 1.

Table 1. List of the plasma spray conditions.

Parameter	Value
dc power (kW)	8
RF power (kW)	90
Pressure (Torr)	400
dc Ar flow rate (slm)	10
Radial Ar flow rate (slm)	140
Tangential Ar flow rate (slm)	30
Powder carrier gas flow rate (slm)	3.6
H2 flow rate (slm)	30
CH4 flow rate (slm)	0 ∼ 6.6
SiO average particle size (μm)	165
Powder feeding rate (g min^−1)	8

Figure 2 FE-SEM images of the raw SiO (a), plasma sprayed (PS-PVD) powder with CH₄ addition (C/Si = 1) (b) and its higher magnitudes (c).

Figure 3 Comparison of the particle size distribution of the PS-PVD powders between the powders produced with different CH₄ additions (volumetric frequency basis).

Figure 4 HR-TEM images of the PS-PVD SiO powders processed (a) without and (b) with 1.1 slm CH₄ gas addition.

Figure 5 Change in the EEL spectra of the Si–L edge within the SiO_x particle of the PS-PVD powders processed with and without CH₄ gas addition. The positions of the EELS analysis are indicated in the STAM HAADF images.

Figure 6 XRD patterns of the PS-PVD powders processed with different CH₄ gas additions.

Table 2. Relative amount (wt%) of phases present in the PS-PVD powder mixture, estimated by Rietveld analysis of the XRD patterns shown in figure 5.

C/Si	nc-Si	3C-SiC	a-SiOx
0	8.6	0.0	91.4
0.25	31.6	0.0	68.4
1	53.8	4.6	41.6
1.5	54.4	13.5	32.1

Figure 7 Change in the initial capacity with voltage for the PS-PVD powders with different C/Si ratios. The battery was charged at a constant current of 0.1 mA, and the cut-off voltage was set to 0 V. The initial efficiency (%) is shown next to the C/Si.

Figure 8 Capacity change with number of cycle for PS-PVD powders processed with different CH₄ gas additions. The battery was charged at a constant current of 0.1 mA for the first three cycles and at 0.5 mA for the rest of the cycles.

Figure 9 Coulombic efficiency change with cycle for the PS-PVD powders processed with different CH₄ gas additions.

Figure 10 Change in the differential capacity with voltage for the PS-PVD powders processed with different CH₄ gas additions at the 1st cycle. Inset: at the 100th cycle.