Experimental methods for preparing silicon-carbon composite materials for lithium-ion batteries
We used solution plasma treatment (SPP) to determine the composition of silicon-CB composites. The results show that SPP is an excellent method for preparing carbon black with a medium-to-micro layered porous structure and high pore volume. (0-22)
In these studies, only organic solvents such as benzene were used to form CB. However, in this study, we investigated the composition of the composite material by relaxing silicon nanoparticles in an organic solvent before plasma discharge.
The experiment was conducted at room temperature and pressure. A pair of mechanical pencil leads were used as electrodes for plasma generation, and since most of the metal wires were sputtered or vaporized by the plasma, it can be inferred that the composite material contains impurities.
Each electrode was covered with a ceramic tube, which was then inserted into a silicone stopper. A pair of electrodes were encapsulated in ceramic tubes, fitted with silicone stoppers, and then placed in a beaker with a diameter of 50 mm and a height of 100 mm (Figure 1). The distance between the electrodes was maintained at 1 mm. The carbon precursor was pure xylene (reagent grade, Sigma-Aldrich), and silicon nanoparticles (uniform particle size = 100 nm, Alfa Aesar) were mixed with xylene. A bipolar pulsed power supply was used to initiate the discharge. The power supply frequency and pulse width were adjusted to 25 kHz and 0.5 s, respectively. After discharge, the discharge solution was filtered through glass fiber paper to obtain any solid compounds present in the solution. The solution was then filtered again; it was monotonized at 80°C, leaving a powdery substance.
Xylene was evaporated. To obtain positive conductivity, the resulting powder was treated in an electric furnace at 700°C under a N2 atmosphere for 1 h. To perform electrochemical evaluation of the silicon-CB composite material, an anode was prepared using a slurry of the silicon-CB composite material (80 wt%) as the active material CB.
(10% component; super P) as a conductive agent, poly(acrylic acid) (PAA; 10%) as a binder in distilled water.
The CR2032 coin cell was assembled in an argon-filled glove box, using 2400 Celgard as separators, lithium foil as counter and reference electrodes, and 1M LiPF6 as polycarbonate vinyl diethyl carbonate (EC=DEC) (1:1 volume). Vinyl fluorocarbonate (FEC) containing 10% of the component was used as the electrolyte. All cells were detected at current densities (Li=Li+) between 0.05 and 3 V at 1 °C.
[372mah=g; Using the BCS805 bio-based battery detection system, charging (lithium extraction) and discharging (lithium thrust) were performed at room temperature.]
