Short answer: The three main inorganic solid electrolyte families are oxide garnets (LLZO), NASICON phosphates (LATP) and sulfides (such as argyrodite Li6PS5Cl). Sulfides conduct lithium ions best and press into dense layers at room temperature but are air-sensitive; LLZO is stable against lithium metal but hard to process; LATP is air-stable and low-cost but reacts with lithium metal.
Comparison of solid electrolyte families
| LLZO (garnet) | LATP (NASICON) | Sulfides (e.g. Li6PS5Cl) | |
|---|---|---|---|
| Typical room-temperature conductivity | about 10⁻⁴ to 10⁻³ S/cm (doped) | about 10⁻⁴ to 10⁻³ S/cm | about 10⁻³ to 10⁻² S/cm |
| Stability vs lithium metal | Good | Poor (Ti⁴⁺ is reduced) | Forms an interphase; often usable |
| Air / moisture | Forms Li2CO3 on the surface | Stable | Reacts with moisture, releases H2S |
| Processing | High-temperature sintering | Sintering | Cold pressing works |
| Typical use | Li-metal anodes, ceramic separators | Coatings, composite electrolytes, cathode side | All-solid-state pellet and pouch cells |
LLZO (Li7La3Zr2O12)
Garnet LLZO needs doping (Al, Ga or Ta) to stabilize its highly conductive cubic phase. It is prized for stability against lithium metal, but surface Li2CO3 and high sintering temperatures make interfaces a challenge.
LATP (Li1.3Al0.3Ti1.7(PO4)3)
LATP is inexpensive and air-stable, and is often used in composite polymer electrolytes or as a protective coating. Because titanium is reduced by lithium metal, it needs an interlayer when used with lithium anodes.
Sulfide electrolytes
Argyrodites such as Li6PS5Cl and thiophosphates such as Li3PS4 reach liquid-like conductivity and deform easily, so they can be densified by pressing. They must be handled under dry, inert conditions. Related sulfide precursors such as lithium sulfide are listed in our electrolyte materials.
Which solid electrolyte should I choose?
- Highest conductivity and cold-pressed cells: sulfides.
- Direct contact with lithium metal: LLZO.
- Air-stable, low-cost composite or coating layer: LATP.
Frequently asked questions
What is the most conductive solid electrolyte?
Sulfide electrolytes, including argyrodites and Li10GeP2S12-type materials, reach 10⁻³ to above 10⁻² S/cm at room temperature.
Why is LLZO doped?
Undoped LLZO forms a tetragonal phase with low conductivity; Al, Ga or Ta doping stabilizes the cubic phase.
Can I source solid electrolyte materials from NanoLithium?
We supply lithium salts, precursors and other materials for solid-state battery research. Contact us to ask about LLZO, LATP and sulfide electrolyte availability.
