Semi-solid electrodes having high rate capability
Embodiments described herein relate generally to electrochemical cells having high rate capability, and more particularly to devices, systems and methods of producing high capacity and high rate capability batteries having relatively thick semi-solid electrodes. In some embodiments, an electrochemical cell includes an anode, a semi-solid cathode that includes a suspension of an active material and a conductive material in a liquid electrolyte, and an ion permeable membrane disposed between the anode and the cathode. The semi-solid cathode has a thickness in the range of about 250 μm-2,500 μm, and the electrochemical cell has an area specific capacity of at least 5 mAh/cm 2 at a C-rate of C/2.
1. An electrochemical cell, comprising:
an anode;
a cathode; and
a separator disposed between the anode and the cathode,
wherein at least one of the anode and the cathode is a slurry electrode that includes about 35% to about 75% by volume of an active material and a conductive material in a liquid electrolyte,
wherein the conductive material includes at least one of graphite, carbon powder, pyrolytic carbon, carbon black, carbon fibers, carbon microfibers, carbon nanotubes, single walled carbon nanotubes, multi walled carbon nanotubes, fullerene carbons, graphene sheets, and aggregate of graphene sheets,
wherein at least one of the anode and the cathode has a thickness of at least about 250 μm, and
wherein the electrochemical cell has an area specific capacity of at least 7 mAh/cm 2 at a C-rate of C/4.
2. The electrochemical cell of claim 1 , wherein the electrochemical cell has an area specific capacity of at least 8 mAh/cm 2 at a C-rate of C/4.
3. The electrochemical cell of claim 1 , wherein the electrochemical cell has an area specific capacity of at least 9 mAh/cm 2 at a C-rate of C/4.
4. The electrochemical cell of claim 1 , wherein the electrochemical cell has an area specific capacity of at least 10 mAh/cm 2 at a C-rate of C/4.
5. The electrochemical cell of claim 1 , wherein the active material is about 45% to about 75% by volume.
6. The electrochemical cell of claim 1 , wherein the conductive material is about 0.5% to about 8% by volume.
7. An electrochemical cell, comprising:
an anode;
a cathode; and
a separator disposed between the anode and the cathode,
wherein at least one of the anode and the cathode is a slurry electrode and includes about 35% to about 75% by volume of an active material and a conductive material in a liquid electrolyte,
wherein the slurry electrode has a thickness of at least 300 μm, and
wherein the electrochemical cell has an area specific capacity of at least 7 mAh/cm 2 at a C-rate of C/4.
8. The electrochemical cell of claim 7 , wherein the slurry electrode having the thickness of at least 300 μm is the cathode.
9. The electrochemical cell of claim 7 , wherein the liquid electrolyte is non-aqueous.
10. The electrochemical cell of claim 7 , wherein the conductive material includes at least one of graphite, carbon powder, pyrolytic carbon, carbon black, carbon fibers, carbon microfibers, carbon nanotubes, single walled carbon nanotubes, multi walled carbon nanotubes fullerene carbons, graphene sheets, and an aggregate of graphene sheets.
11. An electrochemical cell, comprising:
an anode;
a slurry cathode including (a) about 20% to about 75% by volume of an active material, and (b) a conductive material in a liquid electrolyte; and
a separator disposed between the anode and the cathode,
wherein the cathode has a thickness of at least about 250 μm, and
wherein the electrochemical cell has an area specific capacity of at least 7 mAh/cm 2 at a C-rate of C/4.
12. The electrochemical cell of claim 11 , wherein the active material in the cathode includes an ordered rocksalt compound.
13. The electrochemical cell of claim 12 , wherein the ordered rocksalt compound includes at least one of LiCoO 2 , LiCoO 2 doped with Mg, LiNiO 2 , Li(Ni, Co, Al)O 2 , and Li(Ni, Mn, Co)O 2 .
14. The electrochemical cell of claim 11 , wherein the active material in the cathode includes an olivine compound.
15. The electrochemical cell of claim 14 , wherein the olivine compound includes LiMPO 4 , wherein M is at least one of Mn, Fe, Co, and Ni.
16. The electrochemical cell of claim 11 , wherein the conductive material in the cathode is about 0.5% to about 8% by volume.
17. The electrochemical cell of claim 11 , wherein the cathode has a thickness of at least 300 μm.
18. The electrochemical cell of claim 11 , wherein the cathode has a thickness in a range of about 250 μm to about 2,000 μm.