Lithium ion batteries with supplemental lithium
View Patent ↗Supplemental lithium can be used to stabilize lithium ion batteries with lithium rich metal oxides as the positive electrode active material. Dramatic improvements in the specific capacity at long cycling have been obtained. The supplemental lithium can be provided with the negative electrode, or alternatively as a sacrificial material that is subsequently driven into the negative electrode active material. The supplemental lithium can be provided to the negative electrode active material prior to assembly of the battery using electrochemical deposition. The positive electrode active materials can comprise a layered-layered structure comprising manganese as well as nickel and/or cobalt.
1. A lithium ion battery comprising:
a negative electrode consisting essentially of graphitic carbon and an effective amount of extractable supplemental lithium distinct from amounts of lithium provided by cycling positive electrode active material;
a positive electrode comprising layered-layered crystalline composition, which is a cycling active material of the positive electrode, approximately represented by the formula Li 1+x M 1−y O 2−z F z where M is one or more metal elements, x is from about 0.01 to about 0.33, y is from about x−0.2 to about x+0.2 with the proviso that y≧0, and z is from 0 to about 0.2; and
a separator between the negative electrode and the positive electrode,
wherein after 600 cycles at C/3 rate between 4.5V and 2.0V the negative electrode comprises no more than about 1 weight percent transition metals from the positive electrode.
2. The lithium ion battery of claim 1 wherein after 600 cycles at C/3 rate, the negative electrode comprises no more than about 0.25 weight percent transition metals from the positive electrode.
3. A lithium ion battery comprising a positive electrode, a negative electrode consisting essentially of graphitic carbon and extractable supplemental lithium distinct from amounts of lithium provided by cycling positive electrode active material, a separator between the positive electrode and the negative electrode and an electrolyte comprising lithium ions, wherein the positive electrode comprises a layered-layered crystalline composition, which is a cycling active material of the positive electrode, approximately represented by a formula Li 1+x M 1−y O 2−z F z where M is one or more metal elements, x is from about 0.01 to about 0.33, y is from about x−0.2 to about x+0.2 with the proviso that y≧0, and z is from 0 to about 0.2 and wherein after cycling the battery for 20 cycles from 4.5 volts to 2 volts and after discharging the battery to 98% of the discharge capacity, the negative electrode can be removed and electrochemically de-intercalated/de-alloyed with a capacity attributable to supplemental lithium that is at least about 2.5% of the negative electrode capacity with the corresponding removal of lithium from the negative electrode.
4. The lithium ion battery of claim 3 wherein after cycling the battery for 550 cycles at C/3 rate from 4.5 volts to 2 volts and after discharging the battery to 98 percent of capacity, the negative electrode can be removed and electrochemically de-intercalated/de-alloyed with a capacity attributable to supplemental lithium that is at least about 2.5% of the negative electrode capacity with the corresponding removal of lithium from the negative electrode.
5. A lithium ion battery comprising:
a negative electrode consisting essentially of graphitic carbon and an effective amount of extractable supplemental lithium distinct from amounts of lithium provided by cycling positive electrode active material;
a positive electrode comprising a layered-layered crystalline composition, which is a cycling active material of the positive electrode, approximately represented by the formula Li 1+x M 1−y O 2−z F z where M is one or more metal elements, x is from about 0.01 to about 0.33, y is from about x−0.2 to about x+0.2 with the proviso that y≧0, and z is from 0 to about 0.2; and
a separator between the negative electrode and the positive electrode,
wherein from about 300 cycles to about 600 cycles the positive electrode active material has a specific discharge capacity of at least about 90 mAh/g between 3V and 2.5V at a rate of C/3.
6. The lithium ion battery of claim 1 wherein the positive electrode comprises lithium metal oxide that can be approximately represented by a formula Li 1+b Ni α Mn β Co γ A δ O 2 , where b ranges from about 0.05 to about 0.3, α ranges from 0 to about 0.4, β range from about 0.2 to about 0.65, γ ranges from 0 to about 0.46, and δ ranges from about 0 to about 0.15, and where A is Mg, Sr, Ba, Cd, Zn, Al, Ga, B, Zr, Ti, Ca, Ce, Y, Nb, Cr, Fe, V, Li, or combinations thereof.
7. The lithium ion battery of claim 1 wherein the positive electrode comprises lithium metal oxide that can be approximately represented by a formula of xLi 2 MnO 3 .(1−x)LiMO 2 , where M represents one or more metal ions having an average valance of +3, and 0<x<1.
8. The lithium ion battery of claim 1 wherein after cycling the battery for 20 cycles from 4.5 volts to 2.0 volts and after fully discharging the battery to 2.0 volts, the negative electrode can be removed and discharged with a specific capacity of at least about 1 mAh/g with the corresponding removal of lithium from the negative electrode.
9. The lithium ion battery of claim 1 wherein the positive electrode has a room temperature specific discharge capacity at the 200th cycle that is at least about 92.5% of the 5th cycle specific discharge capacity when discharged from the 5th cycle to the 200th cycle at a C/3 rate.
10. The lithium ion battery of claim 3 wherein after 600 cycles at a C/3 rate between 4.5V and 2.0V the negative electrode comprises no more than about 1 weight percent transition metals from the positive electrode.
11. The lithium ion battery of claim 3 wherein the positive electrode has a room temperature specific discharge capacity at the 200th cycle that is at least about 92.5% of the 5th cycle specific discharge capacity when discharged from the 5th cycle to the 200th cycle at a C/3 rate from 4.5V to 2V.
12. The lithium ion battery of claim 3 wherein the battery has a specific discharge capacity at the 45th cycle that is at least about 90% of the 5th cycle specific discharge capacity when discharged from the 5th cycle to the 45th cycle at a C/3 rate at a temperature of 55° C. from 4.5V to 2V.
13. The lithium ion battery of claim 3 wherein from about 300 cycles to about 600 cycles the positive electrode active material has a specific discharge capacity of at least about 90 mAh/g between 3V and 2.5V at a rate of C/3.
14. The lithium ion battery of claim 3 wherein the positive electrode comprises lithium metal oxide that can be approximately represented by a formula Li 1+b Ni α Mn β Co γ A δ O 2 , where b ranges from about 0.05 to about 0.3, α ranges from 0 to about 0.4, β range from about 0.2 to about 0.65, γ ranges from 0 to about 0.46, and δ ranges from about 0 to about 0.15, and where A is Mg, Sr, Ba, Cd, Zn, Al, Ga, B, Zr, Ti, Ca, Ce, Y, Nb, Cr, Fe, V, Li, or combinations thereof.
15. The lithium ion battery of claim 3 wherein the battery has a room temperature specific discharge capacity at the 175th cycle that is at least about 75% of the 5th cycle specific discharge capacity when discharged from the 5th cycle to the 175th cycle at a 1 C rate from 4.5V to 2V.