Energy storage devices
View Patent ↗A novel hybrid lithium-ion anode material based on coaxially coated Si shells on vertically aligned carbon nanofiber (CNF) arrays. The unique cup-stacking graphitic microstructure makes the bare vertically aligned CNF array an effective Li + intercalation medium. Highly reversible Li + intercalation and extraction were observed at high power rates. More importantly, the highly conductive and mechanically stable CNF core optionally supports a coaxially coated amorphous Si shell which has much higher theoretical specific capacity by forming fully lithiated alloy. Addition of surface effect dominant sites in close proximity to the intercalation medium results in a hybrid device that includes advantages of both batteries and capacitors.
1. An electrode comprising:
a conductive substrate;
a plurality of carbon fibers;
an intercalation material dispersed with the plurality of carbon fibers, wherein the intercalation material is configured to reversibly adsorb charge carriers within a bulk of the intercalation material; and
a plurality of nanoparticles that catalyze intercalation of the charge carriers into the bulk of the intercalation material.
2. The electrode of claim 1 , further comprising a binder that holds the plurality of carbon fibers in proximity to the conductive substrate.
3. The electrode of claim 1 , wherein the plurality of carbon fibers are attached to the conductive substrate.
4. The electrode of claim 1 , wherein the plurality of nanoparticles are disposed on a surface of the intercalation material.
5. The electrode of claim 1 , wherein the intercalation material is attached to the plurality of carbon fibers.
6. The electrode of claim 1 , wherein the plurality of nanoparticles comprise carbon.
7. The electrode of claim 1 , wherein the intercalation material comprises silicon.
8. An energy storage system comprising:
a cathode;
an electrolyte; and
an anode, the anode comprising
a conductive substrate;
a plurality of carbon fibers;
an intercalation material dispersed with the plurality of carbon fibers, wherein the intercalation material is configured to reversibly adsorb charge carriers within a bulk of the intercalation material; and
a plurality of nanoparticles that catalyze intercalation of the charge carriers into the bulk of the intercalation material.
9. The energy storage system of claim 8 , further comprising a binder that holds the plurality of carbon fibers in proximity to the conductive substrate.
10. The energy storage system of claim 8 , wherein the plurality of carbon fibers are attached to the conductive substrate.
11. The energy storage system of claim 8 , wherein the plurality of nanoparticles are disposed on a surface of the intercalation material.
12. The energy storage system of claim 8 , wherein the intercalation material is attached to the plurality of carbon fibers.
13. The energy storage system of claim 8 , wherein the plurality of nanoparticles comprise carbon.
14. The energy storage system of claim 8 , wherein the intercalation material comprises silicon.
15. An anode for use in a lithium-ion battery, the anode comprising:
a conductive substrate;
a plurality of carbon nanofibers bound to the conductive substrate by a binder;
a plurality of silicon particles dispersed among the plurality of carbon nanofibers; and
a plurality of nanoparticles that provide surface effect dominant sites to donate electrons to charge carriers via faradaic interactions on surfaces of the nanoparticles.
16. The anode of claim 15 , wherein the plurality of silicon particles have a size between 0.1 μm and 29 μm.
17. The anode of claim 15 , wherein the plurality of carbon nanofibers have a length between 10 μm and 250 μm.
18. The anode of claim 15 , wherein the plurality of silicon particles are configured to reversibly adsorb charge carriers into a bulk of the plurality of silicon particles.
19. The anode of claim 15 , wherein the plurality of silicon particles are disposed on the plurality of carbon nanofibers.
20. The anode of claim 15 , wherein the nanoparticles comprise transition metal oxides, metal nitrides, carbon, activated carbon, graphene, graphite, titanate, crystalline silicon, tin, germanium, metal hydrides, iron phosphates, polyaniline, mesophase carbon, or mixtures thereof.