Electrode materials with mixed particle sizes
The present invention is directed to electrochemical devices and materials thereof. More specifically, embodiments set forth herein provide a low-porosity electrode that includes large particles and small particles. The large particles include electrochemically active material. The small particles include ion conductive electrolyte materials. In some examples, the large particles and small particles are characterized by a dispersity of no higher than 0.5. There are other embodiments as well.
1. A solid state electrode of an electrochemical device comprising:
a first plurality of particles of electrochemically active material, the first plurality of particles having a first particle size distribution characterized by a first dispersity of 0.25 or less and a first median diameter; and
a second plurality of particles of ion conductive material, the second plurality of particles having a second particle size distribution characterized by a second dispersity of 0.25 or less and a second median diameter, the second median diameter being at least three times smaller than the first median diameter;
wherein the electrode is characterized by a porosity of less than 10% by volume.
2. The electrode of claim 1 , wherein the electrode comprises a volume fraction of second particles of less than 20% relative to a total particle volume of the electrode.
3. The electrode of claim 1 , wherein the ion conductive material comprises Li a X b P c S d O e , where X═Si, Ge, Al, Sn, and combinations thereof, and where 5≦a≦15, 0<b≦3, 1≦c≦4, 6≦d≦18 and 0<e≦5.
4. The electrode of claim 1 , wherein the ion conductive material comprises a member selected from the group consisting of Li 2 S—SiS 2 , Li 2 S—SiS 2 —LiI, Li 2 S—SiS 2 —Li 3 MO 4 , Li 2 S—SiS 2 —Li 3 MO 3 , Li 2 S—P 2 S 5 —LiI, and LATS, where M is a member selected from the group consisting of Si, P, Ge, B, Al, Ga, and In.
5. The electrode of claim 1 , further comprising an electron conductive additive, the electron conductive additive comprising acetylene black, carbon black, activated carbon, C65, C45, VGCF, carbon fibers, carbon nanotubes, ketjen black, or a combination thereof.
6. The electrode of claim 1 , further comprising a binder material, the binder material selected from a rubber or a polymer.
7. The electrode of claim 1 , further comprising a percolating network, wherein a fraction of the second plurality of particles participates in the percolating network at a ratio of greater than 80%.
8. The electrode of claim 1 , wherein the total ionic conductivity of the electrode is greater than 1% of the conductivity of the bulk ion conductive material.
9. The electrode of claim 1 , wherein the second median diameter is at least four times smaller than the first median diameter.
10. A solid state battery comprising the solid state electrode of claim 1 , a solid state electrolyte, and a lithium metal anode.
11. A solid state electrochemical electrode comprising:
active materials characterized by a first particle size distribution having a first median particle size;
catholyte materials characterized by a second particle size distribution having a second median particle size;
wherein the volumetric ratio of active materials to catholyte materials is from 99:1 to 1:1; and
wherein the particle size ratio of the first median particle size to the second median particle size is at least 3:1 or greater; and
wherein the electrochemical electrode has a porosity of less than 10% by volume.
12. The electrode of claim 11 , wherein the first particle size distribution has a dispersity of 0.25 or less.
13. The electrode of claim 11 , wherein the second particle size distribution has a dispersity of 0.25 or less.
14. The electrode of claim 11 , further comprising an electron conductive additive, the electron conductive additive comprising acetylene black, carbon black, activated carbon, C65, C45, VGCF, carbon fibers, carbon nanotubes, ketjen black, or a combination thereof.
15. The electrode of claim 11 , further comprising a binder material, the binder material selected from a rubber or a polymer.
16. The electrode of claim 11 , wherein the catholyte materials form a percolating network.
17. The electrode of claim 16 , wherein more than 80% of the catholyte materials in the electrode are bonded within the percolating network.
18. An electrochemical cell comprising
an anode current collector;
an anode in direct contact with the anode current collector;
an electrolyte in direct contact with the anode, the anode being positioned
between the anode current collector and the electrolyte, and the electrolyte being characterized by an ionic conductivity of at least 1 e-4 S/cm; and
a solid state positive electrode in direct contact with the electrolyte and comprising:
active materials characterized by a first particle size distribution having a first median particle size;
catholyte materials characterized by a second particle size distribution having a second median particle size;
wherein the volumetric ratio of active materials to catholyte materials is from 99:1 to 1:1; and
wherein the particle size ratio of the first median particle size to the second median particle size is at least 3:1 or greater; and
wherein the positive electrode has a porosity of less than 10% by volume.
19. The cell of claim 18 , wherein the first particle size distribution has a dispersity of 0.25 or less.
20. The cell of claim 18 , wherein the second particle size distribution has a dispersity of 0.25 or less.
21. The cell of claim 18 , wherein the catholyte materials form a percolating network.
22. The cell of claim 21 , wherein more than 80% of the catholyte materials in the positive electrode are bonded within the percolating network.