Solid-state electrolyte for solid-state rechargeable sodium-ions batteries
The present invention provides a solid-state electrolyte for solid-state rechargeable sodium-ions batteries comprising: —Na in a molar content x of at least 3.50 and of at most 4.00, —Sn in a molar content y of at least 0.50 and of at most 1.00, —As in a molar content z superior to 0.00, preferably of at least 0.10, and of at most 0.50, —S in a molar content of 4.00.
1 . A solid-state electrolyte for solid-state rechargeable sodium-ions batteries comprising:
Na in a molar content x of at least 3.50 and of at most 4.00,
Sn in a molar content y of at least 0.50 and of at most 1.00,
As in a molar content z of 0.21≤z≤0.29, and
S in a molar content of 4.00.
2 . The solid-state electrolyte for solid-state rechargeable sodium-ions batteries according to claim 1 , having a general formula Na x Sn y As z S 4 , wherein 3.55≤x≤3.95.
3 . The solid-state electrolyte for solid-state rechargeable sodium-ions batteries according to claim 2 , wherein 3.70≤x≤3.80.
4 . The solid-state electrolyte for solid-state rechargeable sodium-ions batteries according to claim 1 , wherein 0.55≤y≤0.95.
5 . The solid-state electrolyte for solid-state rechargeable sodium-ions batteries according to claim 4 , wherein 0.70≤y≤0.80.
6 . The solid-state electrolyte for solid-state rechargeable sodium-ions batteries according to claim 1 , wherein 0.24≤z≤0.26.
7 . The solid-state electrolyte for solid-state rechargeable sodium-ions batteries according to claim 1 , wherein 3.70≤x≤3.80, 0.70≤y≤0.80 and 0.21≤z≤0.29.
8 . The solid-state electrolyte for solid-state rechargeable sodium-ions batteries according to claim 1 , having a sodium ionic conductivity of superior to 0.30 mS/cm at a temperature of 30° C. and at least 1.00 mS/cm at a temperature of 60° C.
9 . The solid-state electrolyte for solid-state rechargeable sodium-ions batteries according to claim 1 , comprising a space group of I41/acd having 13.0 Å≤lattice constant a≤15.0 Å, 25.0 Å≤lattice constant c≤30.0 Å, as determined by XRD.
10 . A process for manufacturing the solid-state electrolyte according to any of the preceding claims , said process comprising:
a first step of mixing Na 2 S, SnS 2 , As 2 S 3 , and S powder in an inert atmosphere so as to obtain a mixture;
a second step of pressing said mixture under a pressure between 50 and 400 MPa, so as to obtain a pellet; and
a third step of firing said pellet at a temperature between 300° C. and 700° C. during a period of time comprised between 1 and 20 hours.
11 . A positive electrode for solid-state rechargeable sodium-ions batteries, comprising the solid-state electrolyte according to claim 1 .
12 . A solid-state rechargeable sodium-ions battery comprising the solid-state electrolyte according to claim 1 .