Electrodes, lithium-ion batteries, and methods of making and using same
Described herein are improved composite anodes and lithium-ion batteries made therefrom. Further described are methods of making and using the improved anodes and batteries. In general, the anodes include a porous composite having a plurality of agglomerated nanocomposites. At least one of the plurality of agglomerated nanocomposites is formed from a dendritic particle, which is a three-dimensional, randomly-ordered assembly of nanoparticles of an electrically conducting material and a plurality of discrete non-porous nanoparticles of a non-carbon Group 4A element or mixture thereof disposed on a surface of the dendritic particle. At least one nanocomposite of the plurality of agglomerated nanocomposites has at least a portion of its dendritic particle in electrical communication with at least a portion of a dendritic particle of an adjacent nanocomposite in the plurality of agglomerated nanocomposites.
1. A porous composite comprising:
a plurality of agglomerated nanocomposites, wherein each of the nanocomposites comprises:
a plurality of dendritic particles, wherein the dendritic particles comprise a three-dimensional, randomly-ordered assembly of nanoparticles of carbon;
a plurality of discrete non-porous nanoparticles of silicon disposed on the outer surface of the dendritic particle;
an electrically conductive material joining the nanocomposites together, wherein at least a portion of the nanocomposites are in electrical communication with each other through the electrically conductive material; and
a lithium ion permeable layer disposed on at least a portion of the surface of the joined nanocomposites and forming a total pore volume within the porous composite that has a range of about 1.5 to about 20 times the volume occupied by all of the nanoparticles in the porous composite.
2. The porous composite of claim 1 , wherein the electrically conductive material is a carbon layer.
3. The porous composite of claim 1 , wherein the lithium ion permeable layer is a metal oxide layer.
4. The porous composite of claim 1 , wherein the lithium ion permeable layer is a carbon layer.
5. The porous composite of claim 1 , wherein the lithium ion permeable layer is a metal oxyfluoride layer.
6. The porous composite of claim 1 , wherein the lithium ion permeable layer is a lithium ion permeable polymer layer.
7. The porous composite of claim 1 , wherein a void is present between at least a portion of the lithium ion permeable layer and the joined nanocomposites.
8. The porous composite of claim 1 , wherein the plurality of discrete non-porous nanoparticles of silicon have an average longest dimension of about 5 nanometers to about 200 nanometers.
9. The porous composite of claim 1 , wherein the plurality of discrete non-porous nanoparticles of silicon comprise about 15 weight percent to about 90 weight percent of each nanocomposite.
10. A battery electrode comprising:
a conductive metal substrate; and
a porous composite dispersed in a binder coupled to the conductive metal substrate, wherein the porous composite comprises:
a plurality of agglomerated nanocomposites, wherein each of the plurality of nanocomposites comprises:
a plurality of dendritic particles, wherein the dendritic particles comprise a three-dimensional, randomly-ordered assembly of nanoparticles of carbon; and
a plurality of discrete non-porous nanoparticles of silicon disposed on the outer surface of the dendritic particle;
an electrically conductive material joining the nanocomposites together, wherein at least a portion of the nanocomposites are in electrical communication with each other through the electrically conductive material; and
a lithium ion permeable layer disposed on at least a portion of the surface of the joined nanocomposites and forming a total pore volume within the porous composite that has a range of about 1.5 to about 20 times the volume occupied by all of the nanoparticles in the porous composite.
11. A battery, comprising:
a cathode comprising lithium;
an anode comprising a porous composite dispersed in a binder coupled to a conductive metal substrate, wherein the porous composite comprises:
a plurality of agglomerated nanocomposites, wherein each of the plurality of nanocomposites comprises:
a plurality of dendritic particles, wherein the dendritic particles comprise a three-dimensional, randomly-ordered assembly of nanoparticles of carbon; and
a plurality of discrete non-porous nanoparticles of silicon disposed on the outer surface of the dendritic particle;
an electrically conductive material joining the nanocomposites together, wherein at least a portion of the nanocomposites are in electrical communication with each other through the electrically conductive material; and
a lithium ion permeable layer disposed on at least a portion of the surface of the joined nanocomposites and forming a total pore volume within the porous composite that has a range of about 1.5 to about 20 times the volume occupied by all of the nanoparticles in the porous composite;
a separator, positioned between the cathode and the anode; and
an electrolyte composition disposed between the cathode and the anode.
12. A method of making a porous composite, the method comprising:
obtaining a three-dimensional, randomly-ordered dendritic particle composed of a plurality of discrete nanoparticles of carbon;
disposing a plurality of discrete non-porous nanoparticles of silicon on the outer surface of the dendritic particle to form a nanocomposite particle;
joining the nanocomposite particles together with an electrically conductive material, wherein at least a portion of the nanocomposites are in electrical communication with each other through the electrically conductive material; and
forming a lithium ion permeable layer on at least a portion of the surface of the joined nanocomposites and forming a total pore volume within the porous composite that has a range of about 1.5 to about 20 times the volume occupied by all of the nanoparticles in the porous composite.
13. The porous composite of claim 1 , wherein at least a fraction of the total pore volume is formed such that it is inaccessible to electrolyte solvent.
14. The porous composite of claim 1 , wherein at least a fraction of the total pore volume is formed such that it is accessible to electrolyte solvent.
15. The porous composite of claim 1 , wherein the lithium ion permeable layer is formed by thermal decomposition of a precursor in a gaseous environment.
16. The porous composite of claim 1 , wherein the plurality of discrete non-porous nanoparticles of silicon are deposited by thermal decomposition of a gaseous precursor at sub-atmospheric pressure or by a chemical vapor deposition process at sub-atmospheric pressure.
17. The porous composite of claim 1 , wherein at least some of the dendritic particles are characterized in shape by a branched structure having at least three branches extending from a common vertex.