Supercapacitor
Embodiments provide a hybrid supercapacitor exhibiting high energy and power densities enabled by a high-performance lithium-alloy anode coupled with a porous carbon cathode in an electrolyte containing lithium salt. Embodiments include a size reduced silicon oxide anode, a boron-doped silicon oxide anode, and/or a carbon coated silicon oxide anode, which may improve cycling stability and rate performance. Further embodiments include a hybrid supercapacitor system using a Li-active anode in an electrolyte including LiPF6 in a mixture of ethylene carbonate, diethyl carbonate, and dimethyl carbonate (EC:DEC:DMC, 2:1:2 by vol.) and 10 wt % fluoroethylene carbonate (FEC), which may reduce the self-discharge rate.
1. A supercapacitor system, comprising:
a lithium-alloy anode, a carbon-based cathode, comprising porous carbon and coupled to the lithium-alloy anode; and,
an electrolyte;
wherein the lithium-alloy anode, the carbon-based cathode, and the electrolyte form a supercapacitor system, and
wherein the lithium-alloy anode further comprises crystalline domains dispersed in an amorphous matrix.
2. The supercapacitor recited in claim 1 , wherein the lithium-alloy anode comprises a member of the group consisting of silicon, germanium, and tin.
3. The supercapacitor recited in claim 2 , wherein short charge transport paths of lithium-alloy anodes are generated due to the reduced-sized particles.
4. The supercapacitor recited in claim 2 , wherein lower charge transfer resistance of lithium-alloy anodes is generated by boron doping of the anode.
5. The supercapacitor recited in claim 1 , wherein the porous carbon has a hierarchical porous structure.
6. The supercapacitor recited in claim 1 , wherein the electrolyte includes lithium salts.
7. The supercapacitor recited in claim 6 , wherein the lithium-alloy anode can reversibly react with Li.
8. The supercapacitor recited in claim 1 , wherein the supercapacitor operates between 2.0-4.5 V with a high energy density of 128 Wh/kg at a power density of 1229 W/kg.
9. A supercapacitor, comprising:
a doped lithium-alloy anode, comprising materials that can form an alloy with lithium, the doped lithium-alloy anode further comprising crystalline domains dispersed in an amorphous matrix;
a carbon-based cathode coupled to the lithium-alloy anode, comprising porous carbon; and,
an electrolyte;
wherein the lithium-alloy anode, the carbon-based cathode, and the electrolyte form a supercapacitor.
10. The supercapacitor recited in claim 9 , wherein short charge transport paths and lower charge transfer resistance are generated due to the reduced-sized particles and doping.
11. The supercapacitor recited in claim 9 , wherein the porous carbon has a hierarchical porous structure.
12. The supercapacitor recited in claim 9 , wherein the electrolyte includes lithium salts.
13. The supercapacitor recited in claim 9 , wherein the supercapacitor is configured to operate between 2.0-4.5 V with an energy density of 128 Wh/kg at a power density of 1229 W/kg.
14. The supercapacitor of claim 9 , wherein the anode comprises a material selected from the group consisting of silicon, germanium, and tin.