Methods of fabricating porous ceramic electrodes for solid state battery applications
View Patent ↗Compositions and methods for the fabrication of electrode and porous lithium-garnet electrolyte scaffolds for use in solid state batteries and other devices are provided. The methods produce porous structures using phase inversion or high shear compaction processes to fabricate a solid-state battery electrode material from LLZO electrolytes. Engineered electrode structures with a porous scaffold of solid electrolyte material provide lower interfacial resistances and a mechanical support for a thin solid electrode layer improving performance.
1. A method of forming a porous tape structure, the method comprising:
(a) forming a slurry of LLZO powder, a binder and a solvent;
(b) tape casting the slurry on a substrate to form a LLZO tape;
(c) applying a sacrificial layer on the LLZO tape to produce a bi-layered LLZO tape;
(d) immersing the bi-layered LLZO tape in water to induce solvent/water exchange;
(e) removing the bi-layered LLZO tape from the water and drying the bi-layered LLZO tape; and
(f) heating the bi-layered LLZO tape to remove the sacrificial layer and sinter the LLZO tape to produce a sintered LLZO tape;
(g) wherein a sintered LLZO tape with elongate pores with a length aligned perpendicularly to a top surface of the sintered LLZO tape is produced;
(h) wherein the water for solvent/water exchange further comprises a lithium salt selected from the group consisting of Li 2 CO 3 , LiCl, LiOH, LiNO 3 and Li 2 SO 4 ; and
(i) wherein lithium loss from solid materials during solvent exchange is inhibited.
2. The method of claim 1 , wherein the sacrificial layer is a material selected from the group of materials consisting of poly(methyl methacrylate) (PMMA), carbon, graphite, camphor, naphthalene and a polymer.
3. The method of claim 1 , wherein the slurry further comprises one or more selected from the group of Li 2 CO 3 , MgO, a dispersant and a wetting agent.
4. The method of claim 1 , further comprising:
removing binder from the dry bi-layered LLZO tape;
sintering the bi-layered LLZO tape after binder removal; and
infiltrating the sintered LLZO tape with lithium nickel manganese cobalt oxide (NMC).