Method for preparing a solid-state battery by sintering under pulsating current

A process for producing a bulk all-solid-state Li-ion battery with a monolithic body having at least one negative-electrode composite layer and at least one positive-electrode composite layer, said layers being separated from one another by at least one intermediate solid-electrolyte layer, said process comprising the steps of:

• preparing a pulverulent mixture (MP1) comprising at least one powder of an active negative-electrode material, at least one powder of a solid electrolyte, and at least one powder of electron-conductivity providing agent;
• and
• preparing a pulverulent mixture (MP2) comprising at least one powder of an active lithium-based positive-electrode material, at least one powder of a solid electrolyte, and at least one powder of electron-conductivity providing agent,
• wherein:
• the battery is formed in a single step by superposing at least one layer of said pulverulent mixture MP1 and at least one layer of said pulverulent mixture MP2, said layers being separated from one another by at least one intermediate layer of a solid electrolyte in pulverulent form, and simultaneously sintering these sets of three layers in pulverulent form, at a pressure of at least 20 MPa, using a pulsed current;
• the particle size of the solid electrolyte in pulverulent form is 5 μm or less;
• the solid-electrolyte content in each of the pulverulent mixtures MP1 and MP2 independently varies from 35 to 80 wt %;
• the content of the electron-conductivity providing agent in each of the pulverulent mixtures MP1 and MP2 independently varies from 2 to 25 wt %;
• and
• the active electrode material content in each of the pulverulent mixtures MP1 and MP2 independently varies from 20 to 85 wt %.