Details
Sulfide solid electrolyte, lithium phosphorus sulfur Li5.5PS4.5Cl1.5 for solid-state lithium batteries
Li5.5PS4.5Cl1.5 is used as a high-performance solid-state battery separator, with better ion conductivity and air stability than Li6PS5Cl
Sulfide Electrolyte Powder Ionic Conductivity Test:
1. The ionic conductivity of sulfide solid electrolyte powder increases with increasing tableting pressure. Above 400 MPa, the ionic conductivity tends to stabilize. Excessive pressure may even cause internal cracking and delamination of the tablet, resulting in inaccurate test values. Therefore, tableting is generally performed at a pressure of 200-400 MPa.
2. A stainless steel post is used as a blocking electrode in the cold-pressed green sheet. Applying a pressure of at least 30 MPa on both sides ensures good contact between the electrode and the electrolyte.
3. Testing Procedure:
① Tableting: Pour 200 mg of electrolyte powder into a mold with an inner diameter of 10 mm and apply a pressure of 350 MPa to the tablet.
② Measurement: Use a vernier caliper depth gauge to measure the thickness of the electrolyte sheet in the mold.
③ Assembly: After assembly, apply 350 MPa of pressure, maintain pressure using a steel pressure gauge, and then test.
④ EIS Test: Connect to the electrochemical workstation, set the test parameters, and start the test. The AC impedance test frequency range is 1 MHz to 1 Hz, with a voltage amplitude of 10 mV.
⑤ Calculation of Ionic Conductivity: Because sulfide materials are soft and have good interparticle contact, the AC impedance curve appears as a straight line inclined approximately 45° upward, with no obvious grain boundary capacitance signal. The intersection of the curve with the real axis Z' is used as the total impedance for calculating the ionic conductivity.
Important Notes and Usage Recommendations:
1. Operating Environment: All operations must be performed in a glove box filled with high-purity argon (O₂ & H₂O < 0.1 ppm). Any exposure to air will cause material decomposition, performance failure, and the generation of toxic gases (H₂S).
2. Personal Protection Equipment (PPE): Even when working in a glove box, it is recommended to wear chemical-resistant gloves (such as nitrile rubber gloves). If removal is required, a protective mask, goggles, and an anti-static lab coat must be worn.
Hazard Statements:
1. Contact with water may release hydrogen sulfide gas, which is colorless and highly toxic. It has a rotten egg odor at low concentrations and is odorless at high concentrations. It may spontaneously ignite.
2. Fatal if swallowed, in contact with skin, or inhaled.
3. Can cause severe skin burns and eye damage.
4. Extremely toxic to aquatic life.
Precautionary Statements:
1. Avoid contact with water.
2. Operate in an inert gas glove box to protect from moisture.
3. Wear protective gloves/protective clothing/eye protection/face protection.
4. Wash thoroughly after handling.
5. Do not eat, drink, or smoke when using this product.
6. Do not inhale dust/fumes/gases/mist/vapors/spray.
7. Avoid release to the environment.
Sulfide solid electrolytes. Li5.5PS4.5Cl1.5 is used in solid-state lithium batteries. In sulfide solid electrolytes, sulfur replaces oxygen, which increases the cell volume, expands the Li+ transport channel size, weakens the attraction and binding of Li+ by the structure, and increases the carrier concentration. Therefore, sulfide electrolytes have relatively high ionic conductivity among several solid electrolytes. Compared with Li6PS5Cl, the increased chlorine doping ratio further improves the ionic conductivity. However, on the other hand, it is prone to producing toxic gases, and its stability in humid air needs improvement.
| Test items | Detection value | Detection methods | |
| Appearance | Grayish-white powder, uniform and free of foreign matter | Visual inspection | |
| phase of matter | Sulfur-silver-germanium ore | X-ray diffraction instrument | |
| Particle size | D10(μm) | 0.18 | Particle size analyzer |
| D50(μm) | 0.32 | ||
| D90(μm) | 1.26 | ||
| D99(μm) | 3.01 | ||
| Ionic conductivity (mS/cm) | 6.75 | Electrochemical impedance spectroscopy was performed at 28℃, and the tablets were pressed at 350 MPa. | |
| Electron conductivity (nS/cm) | 8.42 | Electrochemical impedance spectroscopy (EIS) was performed at 28°C, and the tablets were pressed at 350 MPa. | |
| Test conditions: (1) XRD test: Samples are prepared in an inert atmosphere glove box to avoid polar solvent atmosphere. The sample surface is sealed with a protective film to isolate moisture interference during the test. (2) Ionic conductivity test: Take 100mg of powder, mold diameter 10mm, apply 350MPa pressure to form a film, maintain pressure 350MPa, test EIS: frequency 1MHZ~1Hz, disturbance voltage 10mV. (3) Electronic conductivity test: Take 100mg of powder, mold diameter 10mm, apply 350MPa pressure to form a film, maintain pressure 350MPa, test DCP: constant voltage 0.5V, test time 3600s. |
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| Note: (1) It has a foul odor and a melting point of 650-700℃. It is non-flammable. (2) It is soluble in water, producing highly toxic hydrogen sulfide gas. It is soluble in some organic solvents such as alcohols and ethers. (3) Toxicity: It can cause poisoning if swallowed, and direct skin contact can easily cause burns. It is easily denatured in the air to produce highly toxic sulfur gas. (4) Stability: It is stable in an inert atmosphere (Ar/N2) at room temperature. It denatures when exposed to air and can be exposed to a dew point of -45℃ for a short time. Surrounding ignition sources may cause the release of hazardous vapors. |
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