Ionic conductivity in silicon electrolyte composite particles
Processes for the manufacture of porous particulates for use in lithium ion batteries are described. The porous materials include silicon active materials carried in a continuous matrix that includes a carbon phase and a solid-electrolyte phase.
1. A porous microparticulate comprising:
about 5 wt. % to about 80 wt. % dry basis of a carbon matrix,
about 5 wt. % to about 50 wt. % dry basis of a plurality of solid-electrolyte nanoparticles, and
about 5 wt. % to about 90 wt. % dry basis of a plurality of silicon nanoparticles;
wherein the porous microparticulate has an average diameter of about 1 μm to about 100 μm.
2. A process of preparing a porous particulate for use in a lithium ion battery, the process comprising:
providing a porous microparticulate, having an average diameter of about 1 m to about 100 μm, and including about 5 wt. % to about 80 wt. % dry basis of a carbon matrix, about 5 wt. % to about 50 wt. % dry basis of a plurality of solid-sulfide-electrolyte nanoparticles, and about 5 wt. % to about 90 wt. % dry basis of a plurality of silicon nanoparticles; and then
admixing the porous microparticulate with a polysulfide solution thereby interconnecting the solid-sulfide-electrolyte nanoparticles and forming a solid-electrolyte phase.
3. The process of claim 2 , wherein forming the solid-electrolyte phase includes heating the interconnected solid-sulfide-electrolyte nanoparticles to a temperature of about 50° C. to about 600° C.
4. The process of claim 2 , wherein forming the solid-electrolyte phase includes heating the admixture of the porous microparticulate and the polysulfide solution to a temperature of about 30° C. to a polysulfide solution solvent boiling point.
5. The process of claim 2 , the polysulfide solution includes a polysulfide and a solvent.
6. The process of claim 5 , wherein the polysulfide is a lithium polysulfide having the formula Li 2 S x where x is in the range of 1 to about 12.
7. The process of claim 5 , wherein the solvent is an ether.
8. The process of claim 7 , wherein the ether is selected from tetrahydrofuran (THF), tetrahydropyran, 2,2,5,5-tetramethyl tetrahydrofuran, 2-methyl tetrahydrofuran, methyl t-butyl ether, ethyl t-butyl ether, 1,4-dioxane, 1,3-dioxane, dimethoxyethane, diisopropylether, dibutyl ether, diethyl ether, and mixtures thereof.
9. The process of claim 2 , wherein solid-sulfide-electrolyte nanoparticles have a formula of Li x M y S z where M includes B and/or P, where x, y, and z are positive integers, and have an electrolyte nanoparticle S to M ratio of z:y; and
wherein the solid-electrolyte phase has a formula of Li x′ M y′ S z′ where M includes B and/or P, and where x′, y′, and z′ are positive integers, and has an electrolyte phase S to M ratio of z′:y′;
wherein the electrolyte phase S to M ratio is greater than the electrolyte nanoparticle S to M ratio.
10. The process of claim 9 , wherein M further includes As, Ge, Ga, Sb, Si, Sn, Al, In, Ti, V, Nb, Ta, and/or Zn.
11. The process of claim 10 , wherein M includes Si, Sn, Ge, and/or Zn.
12. The process of claim 2 , wherein solid-sulfide-electrolyte nanoparticles have a formula of Li X M y S z R n , where M includes B and/or P, where R is a halide, and where x, y, and z are positive integers, and have an electrolyte nanoparticle S to M ratio of z:y; and
wherein the solid-electrolyte phase has a formula of Li x′ M y′ S z′ R n′ where M includes B and/or P, where R is a halide, and where x′, y′, z′, and n′ are positive integers, and has an electrolyte phase S to M ratio of z′:y′; and
wherein the electrolyte phase S to M ratio is greater than the electrolyte nanoparticle S to M ratio.
13. The process of claim 2 , wherein the porous microparticulate is provided by
forming a plurality of admixture microparticulates, having an average diameter of about 1 μm to about 100 μm, the admixture microparticulates include about 5 wt. % to about 80 wt. % dry basis of the carbon matrix precursor, about 5 wt. % to about 50 wt. % dry basis of the plurality of solid-electrolyte nanoparticles, and about 5 wt. % to about 90 wt. % dry basis of the plurality of silicon nanoparticles; and then
reducing the carbon matrix precursor to form the carbon matrix.
14. The process of claim 13 , wherein the admixture microparticulates are formed by a spray drying process.
15. The process of claim 2 , wherein the porous microparticulate is provided by forming a plurality of admixture microparticulates, having an average diameter of about 1 μm to about 100 μm, the admixture microparticulates include about 5 wt. % to about 80 wt dry basis of the carbon matrix precursor, about 5 wt. % to about 50 wt. % dry basis of the plurality of solid-electrolyte nanoparticles, and about 5 wt. % to about 90 wt. % dry basis of the plurality of silicon nanoparticles; and then
crosslinking the carbon matrix precursor to provide the carbon matrix.
16. The process of claim 2 , wherein the porous microparticulate further include about 1 wt. % to about 20 wt. % dry basis of a conductive agent.
17. The process of claim 16 , wherein the conductive agent is a conductive carbon.
18. A process of preparing a porous particulate for use in a lithium ion battery, the process comprising:
providing a porous microparticulate, having an average diameter of about 1 m to about 100 μm, and including about 5 wt. % to about 80 wt. % dry basis of a carbon matrix, about 5 wt. % to about 50 wt. % dry basis of a plurality of solid-sulfide-electrolyte nanoparticles, and about 5 wt. % to about 90 wt. % dry basis of a plurality of silicon nanoparticles; and then
admixing the porous microparticulate with a sulfur solution thereby interconnecting the solid-sulfide-electrolyte nanoparticles and forming a solid-electrolyte phase.
19. The process of claim 18 , wherein the sulfur solution includes a sulfur compound and a solvent;
wherein the sulfur compound is selected from sulfur, phosphorous pentasulfide, boron sulfide, and a mixture thereof; and
wherein the solvent is selected from carbon disulfide, pyridine, and a mixture thereof.
20. The process of claim 19 , wherein interconnecting the solid-sulfide-electrolyte nanoparticles and forming the solid-electrolyte phase includes heating the admixture of the porous microparticulate and the sulfur compound to a temperature in the range of about 50° C. to about 500° C.
21. The process of claim 19 , wherein the sulfur solution includes sulfur and carbon disulfide.
22. The process of claim 19 , wherein the sulfur solution includes phosphorous pentasulfide and carbon disulfide and/or pyridine.
23. The process of claim 19 , wherein the sulfur solution includes boron sulfide and pyridine.