Li Mn-RICH CATHODE FOR HIGH ENERGY Li-ION BATTERY

Abstract

A compound for use in a lithium, manganese-rich cathode for a Li-ion battery is doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 including Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 doped with Na.sup.+, Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 doped with Co.sup.3+, or Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 dual doped with Na.sup.+ and Co.sup.3+. A lithium, manganese-rich cathode for an Li-ion battery includes the aforementioned compound. A lithium-ion battery includes an anode, a cathode, and an electrolyte, wherein the cathode is the aforementioned lithium, manganese-rich cathode.

Claims

1.-18. (canceled)

19. A lithium-ion battery comprising an anode, a cathode, and an electrolyte, wherein the cathode comprises Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 doped with Na.sup.+, Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 doped with Co.sup.3+, or Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 dual doped with Na.sup.+ and Co.sup.3+.

20. The lithium-ion battery of claim 19, wherein the doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 is Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 doped with Na.sup.+.

21. The lithium-ion battery of claim 20, wherein the doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 is Li.sub.1.175Na.sub.0.025Ni.sub.0.2Mn.sub.0.6O.sub.2.

22. The lithium-ion battery of claim 20, wherein the doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 is Li.sub.1.15Na.sub.0.05Ni.sub.0.2Mn.sub.0.6O.sub.2.

23. The lithium-ion battery of claim 19, wherein the doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 is Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 doped with Co.sup.3+.

24. The lithium-ion battery of claim 23, wherein the doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 is Li.sub.1.195Co.sub.0.025Ni.sub.0.195Mn.sub.0.585O.sub.2.

25. The lithium-ion battery of claim 23, wherein the doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 is Li.sub.1.19Co.sub.0.05Ni.sub.0.19Mn.sub.0.57O.sub.2.

26. The lithium-ion battery of claim 19, wherein the doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 is dual doped with Na.sup.+ and Co.sup.3+.

27. The lithium-ion battery of claim 26, wherein the doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 is Li.sub.1.17Na.sub.0.025Co.sub.0.025Ni.sub.0.195Mn.sub.0.585O.sub.2.

28. The lithium-ion battery of claim 26, wherein the doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 is Li.sub.1.155Na.sub.0.0375Co.sub.0.0375Ni.sub.0.1925Mn.sub.0.5775O.sub.2.

29. Doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2, comprising Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 doped with Na.sup.+, Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 doped with Co.sup.3+, or Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 dual doped with Na.sup.+ and Co.sup.3+.

30. The doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 of claim 29, wherein the doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 is Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 doped with Na.sup.+.

31. The doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 of claim 30, wherein the doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 is Li.sub.1.175Na.sub.0.025Ni.sub.0.2Mn.sub.0.6O.sub.2.

32. The doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 of claim 30, wherein the doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 is Li.sub.1.15Na.sub.0.05Ni.sub.0.2Mn.sub.0.6O.sub.2

33. The doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 of claim 29, wherein the doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 is Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 doped with Co.sup.3+.

34. The doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 of claim 33, wherein the doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 is Li.sub.1.195Co.sub.0.025Ni.sub.0.195Mn.sub.0.585O.sub.2.

35. The doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 of claim 33, wherein the doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 is Li.sub.1.19Co.sub.0.05Ni.sub.0.19Mn.sub.0.57O.sub.2.

36. The doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 of claim 29, wherein the doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 is dual doped with Na.sup.+ and Co.sup.3+.

37. The doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 of claim 36, wherein the doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 is Li.sub.1.17Na.sub.0.025Co.sub.0.025Ni.sub.0.195Mn.sub.0.585O.sub.2.

38. The doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 of claim 36, wherein the doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 is Li.sub.1.155Na.sub.0.0375Co.sub.0.0375Ni.sub.0.1925Mn.sub.0.5775O.sub.2.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0027] Example embodiments of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawing in which:

[0028] FIG. 1 shows an X-ray diffraction pattern for Na.sup.+ doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 (LNMO1226) embodiments of the present disclosure.

[0029] FIG. 2 shows an X-ray diffraction pattern for Co.sup.3+ doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 (LNMO1226) embodiments of the present disclosure.

[0030] FIG. 3 shows an X-ray diffraction pattern for Na.sup.+/Co.sup.3+ dual doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 (LNMO1226) embodiments of the present disclosure.

[0031] FIG. 4 shows graphs of specific capacity vs. cycle number and corresponding tables including embodiments of Co.sup.3+ doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 of the present disclosure.

[0032] FIG. 5 shows graphs of specific capacity vs. cycle number and corresponding tables including embodiments of Na.sup.+ doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 of the present disclosure.

[0033] FIG. 6 shows graphs of specific capacity vs. cycle number and corresponding tables including embodiments of Na.sup.+ Co.sup.3+ dual doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 of the present disclosure.

[0034] FIG. 7 is a graph showing the specific capacity for Na doped, Co doped, and Na/Co doped embodiments of the present disclosure compared with embodiments doped with other dopants.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0035] As mentioned above, the present disclosure provides doped compounds for use in LMR cathodes for Li-ion batteries.

[0036] The major concern for lithium, manganese-rich (LMR) cathodes is the low capacity retention when charging to high voltages (>4.7V). To facilitate the industry application of LMR, the LMR cathode is only charged to high voltage in the formation cycle and cycles within a narrow voltage window (2-4.5V or 2.5-4.45V) in the following cycles. Although the retention can be improved, the capacity and energy density are compromised. The present disclosure addresses this issue experimentally by high-throughput screening suitable dopants for improving capacity within a narrow cycling window. It was found that Nat, Co.sup.3+ and their dual doping can dramatically increase the capacity, without sacrificing retention. This new finding is significantly different than the single dopant strategy reported in the literature as the strategy of the present disclosure uses dual dopants in some embodiments of the present disclosure. The combination of Na.sup.+ and Co.sup.3+ further improves the electrochemical performance compared with a single dopant such as Ca.sup.2+.

[0037] Thus, Na.sup.+ and Co.sup.3+ dual dopants are applied in LMR Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 in some embodiments of the present disclosure. The capacity increases with this strategy. In particular, the initial capacity is improved by Na.sup.+ and Co.sup.3+ dual dopants in Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2.

[0038] The lithium-containing oxide in this disclosure can be made by a solid-state method and doped by a doping method in the art, except that the doping is with two dopants rather than a single dopant in some embodiments of the present disclosure. A cathode can then be formed from by a cathode manufacturing method in the art, except that the material used to form the cathode is the dual doped lithium-containing oxide in some embodiments of the present disclosure rather than another material.

[0039] The cathode can then be used in a lithium-ion battery comprising an anode, a cathode, and an electrolyte, particularly a high-energy Li-ion battery. The battery can be formed by a battery manufacturing method in the art, except that the cathode used to form the battery is a cathode of the present disclosure, which contains the dual doped lithium-containing oxide in some embodiments of the present disclosure rather than another material.

[0040] Specific embodiments of the present disclosure were synthesized and tested according to the following synthesis and test protocol for doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 (LNMO1226).

[0041] In a total of 500 mg Ni.sub.0.25Mn.sub.0.75(OH).sub.2, Li.sub.2CO.sub.3 (5% excess to compensate the Li loss at high temperature) and Na.sub.2CO.sub.3 and/or Co.sub.3O.sub.4 were dosed into crucibles and mixed as appropriate for Na doped, Co doped, and NaCo doped embodiments.

[0042] To synthesize LNMO1266, the temperature was ramped to 600 C. within 2 h and held at 600 C. for 1h before ramping to the final sinter temperature (950 C.) and holding for 12 h.

[0043] The product was ground by hand in mortar and pestle to reduce the agglomeration.

[0044] 350 mg of product was mixed with 100 mg carbon and 1g 5% PVDF/NMP by a Thinky mixer.

[0045] The slurry was cast on Al foil and dried overnight before calendering and punching to make coin cells.

[0046] The specific embodiments of the present disclosure will now be described by way of the figures.

[0047] FIG. 1 is an X-ray diffraction pattern for Na.sup.+ doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 (LNMO1226) embodiments of the present disclosure showing high phase purity, namely, Li.sub.1.1875Na.sub.0.0125Ni.sub.0.2Mn.sub.0.6O.sub.2, Li.sub.1.175Na.sub.0.025Ni.sub.0.2Mn.sub.0.6O.sub.2, Li.sub.1.1625Na.sub.0.0375Ni.sub.0.2Mn.sub.0.6O.sub.2, Li.sub.1.15Na.sub.0.05Ni.sub.0.2Mn.sub.0.6O.sub.2, and Li.sub.1.1375Na.sub.0.0625Ni.sub.0.2Mn.sub.0.6O.sub.2, as well as undoped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 for comparison.

[0048] FIG. 2 is an X-ray diffraction pattern for Co.sup.3+ doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 (LNMO1226) embodiments of the present disclosure showing high phase purity, namely, Li.sub.1.1975Co.sub.0.0125Ni.sub.0.1975Mn.sub.0.5925O.sub.2, Li.sub.1.195Co.sub.0.025Ni.sub.0.195Mn.sub.0.585O.sub.2, Li.sub.1.1925Co.sub.0.0375Ni.sub.0.1925Mn.sub.0.5775O.sub.2, Li.sub.1.19Co.sub.0.05Ni.sub.0.19Mn.sub.0.57O.sub.2, and Li.sub.1.1875Co.sub.0.0625Ni.sub.0.1875Mn.sub.0.5625O.sub.2, as well as undoped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 for comparison.

[0049] FIG. 3 is an X-ray diffraction pattern for Na.sup.+/Co.sup.3+ dual doped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 (LNMO1226) embodiments of the present disclosure showing high phase purity, namely, Li.sub.1.185Na.sub.0.0125Co.sub.0.0125Ni.sub.0.1975Mn.sub.0.5925O.sub.2, Li.sub.1.1825Na.sub.0.0125Co.sub.0.025Ni.sub.0.195Mn.sub.0.585O.sub.2, Li.sub.1.18Na.sub.0.0125Co.sub.0.0375Ni.sub.0.1925Mn.sub.0.5775O.sub.2, Li.sub.1.1725Na.sub.0.025Co.sub.0.0125Ni.sub.0.1975Mn.sub.0.5925O.sub.2, Li.sub.1.17Na.sub.0.025Co.sub.0.025Ni.sub.0.195Mn.sub.0.585O.sub.2, Li.sub.1.1675Na.sub.0.025Co.sub.0.0375Ni.sub.0.1925Mn.sub.0.5775O.sub.2, Li.sub.1.16Na.sub.0.0375Co.sub.0.0125Ni.sub.0.1975Mn.sub.0.5925O.sub.2, Li.sub.1.1575Na.sub.0.0375Co.sub.0.025Ni.sub.0.195Mn.sub.0.585O.sub.2, and Li.sub.1.155Na.sub.0.0375Co.sub.0.0375Ni.sub.0.1925Mn.sub.0.5775O.sub.2, as well as undoped Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 for comparison.

[0050] FIG. 4 shows graphs of specific capacity vs. cycle number (wherein the battery is only charged to a high voltage of 4.8V in the formation cycle and is charged within a narrow voltage window of 2.5 to 4.5V in subsequent cycles, or wherein the battery is only charged to a high voltage of 4.7V in the formation cycle and is charged within a narrow voltage window of 2.5 to 4.45V subsequently) and corresponding tables including Co.sup.3+ doped embodiments of the present disclosure, namely, Li.sub.1.195Co.sub.0.025Ni.sub.0.195Mn.sub.0.585O.sub.2 (Co25) and Li.sub.1.19Co.sub.0.05Ni.sub.0.19Mn.sub.0.57O.sub.2 (Co50), as well as Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 (LNMO1226). FIG. 4 shows that Co.sup.3+ doping decreases retention, but it is still basically >90% after 50 cycles, as can also be seen from the results shown in Tables 1A and 1B below.

TABLE-US-00001 TABLE 1A Co.sup.3+ doping, 2.5-4.8 V 0.1C & 2.5-4.5 V 0.2C & 2.5-4.5 V 0.5C, 25 C. Retention Capacity.sub. Capacity.sub. Capacity.sub. after 50 1st cycle 2nd cycle 3rd cycle cycles (mAh/g) (mAh/g) (mAh/g) % LNMO1226 Cell1 244.1144 211.7219 197.3397 Cell2 250.4214 217.4582 203.2472 Cell3 251.8348 218.5256 204.5882 Average 248.7902 215.9019 201.7251 92.1 Co25 Cell1 261.3304 223.4406 207.5919 Cell2 275.6688 224.7872 207.7619 Average 268.4996 224.1139 207.6769 90.5 Co50 Cell1 263.8921 222.6738 207.7081 Cell2 264.2317 222.1871 206.2563 Cell3 260.2167 221.6331 205.4695 Average 262.7801 222.1647 206.478 89.7

TABLE-US-00002 TABLE 1B Co.sup.3+ doping, 2.5-4.7 V 0.1C & 2.5-4.45 V 0.2C, 25 C. Retention Capacity_1st Capacity_2nd after 50 cycle cycle cycles (mAh/g) (mAh/g) % LNMO1226 Cell1 242.9077 202.0012 Cell2 242.392 201.6998 Average 242.6499 201.8505 95.6 Co25 Cell1 263.453 216.3107 Cell2 254.0439 211.157 Average 258.7485 213.7339 95.2 Co50 Cell1 256.7379 212.3989 Cell2 257.071 212.0502 Average 256.9045 212.2246 94.6

[0051] As can be seen from the results presented above, Co.sup.3+ doping decreases retention, but it is still basically >90% after 50 cycles.

[0052] FIG. 5 shows graphs of specific capacity vs. cycle number (wherein the battery is only charged to a high voltage of 4.8V in the formation cycle and is charged within a narrow voltage window of 2.5 to 4.5V in subsequent cycles, or wherein the battery is only charged to a high voltage of 4.7V in the formation cycle and is charged within a narrow voltage window of 2.5 to 4.45V subsequently) and corresponding tables including Na.sup.+ doped embodiments of the present disclosure, namely, Li.sub.1.175Na.sub.0.025Ni.sub.0.2Mn.sub.0.6O.sub.2 (Na25) and Li.sub.1.15Na.sub.0.05Ni.sub.0.2Mn.sub.0.6O.sub.2 (Na50), as well as Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 (LNMO1226). FIG. 5 shows that Na.sup.+ doping decreases retention, but it is still >90% after 50 cycles, as can also be seen from the results shown in Tables 2A and 2B below.

TABLE-US-00003 TABLE 2A Na.sup.+ doping, 2.5-4.8 V 0.1C & 2.5-4.5 V 0.2C & 2.5-4.5 V 0.5C, 25 C. Retention Capacity.sub. Capacity.sub. Capacity.sub. after 50 1st cycle cycle 2nd 3rd cycle cycles (mAh/g) (mAh/g) (mAh/g) % LNMO1226 Cell1 244.1144 211.7219 197.3397 Cell2 250.4214 217.4582 203.2472 Cell3 251.8348 218.5256 204.5882 Average 248.7902 215.9019 201.7251 92.1 Na25 Cell1 259.2477 221.1027 206.7947 Cell2 260.0921 224.3155 209.6461 Average 259.6699 222.7091 208.2204 91.0 Na50 Cell1 257.2971 220.7668 207.2523 Cell2 264.8309 223.0754 208.271 Cell3 257.0867 218.6203 203.7837 Average 259.7382 220.8208 206.4357 91.4

TABLE-US-00004 TABLE 2B Na.sup.+ doping, 2.5-4.7 V 0.1C & 2.5-4.45 V 0.2C, 25 C. Retention Capacity_1st Capacity_2nd after 50 cycle cycle cycles (mAh/g) (mAh/g) % LNMO1226 Cell1 242.9077 202.0012 Cell2 242.392 201.6998 Average 242.6499 201.8505 95.6 Na25 Cell1 260.3904 212.4406 Cell2 258.2258 211.3958 Average 259.3081 211.9182 93.1 Na50 Cell1 252.6883 207.5034 Cell2 251.912 206.4744 Average 252.3002 206.9889 93.1

[0053] As can be seen from the results presented above, Na.sup.+ doping decreases retention, but it is still >90% after 50 cycles.

[0054] FIG. 6 shows graphs of specific capacity vs. cycle number (wherein the battery is only charged to a high voltage of 4.8V in the formation cycle and is charged within a narrow voltage window of 2.5 to 4.5V in subsequent cycles, or wherein the battery is only charged to a high voltage of 4.7V in the formation cycle and is charged within a narrow voltage window of 2.5 to 4.45V subsequently) and corresponding tables including Na.sup.+ Co.sup.3+ dual doped embodiments of the present disclosure, namely, Li.sub.1.17Na.sub.0.025Co.sub.0.025Ni.sub.0.195Mn.sub.0.585O.sub.2 (Na25Co25) and Li.sub.1.155Na.sub.0.0375Co.sub.0.0375Ni.sub.0.1925Mn.sub.0.5775O.sub.2 (Na375Co375), as well as a comparison embodiment, namely. Li.sub.1.2Ni.sub.0.2Mn.sub.0.6O.sub.2 (LNMO1226). FIG. 6 shows that Na.sup.+Co.sup.3+ dual doping increases the capacity. as can also be seen from the results shown in Table 3A and 3B below.

TABLE-US-00005 TABLE 3A Na.sup.+Co.sup.3+ doping, 2.5-4.8 V 0.1C & 2.5-4.5 V 0.2C & 2.5-4.5 V 0.5C, 25 C. Retention Capacity.sub. Capacity.sub. Capacity.sub. after 50 1st cycle 2nd cycle 3rd cycle cycles (mAh/g) (mAh/g) (mAh/g) % LNMO1226 Cell1 244.1144 211.7219 197.3397 Cell2 250.4214 217.4582 203.2472 Cell3 251.8348 218.5256 204.5882 Average 248.7902 215.9019 201.7251 92.1 Na25Co25 Cell1 262.8765 225.7146 209.4289 Cell2 263.2205 226.2195 210.2427 Average 263.0485 225.9671 209.8358 89.2 Na375Co375 Cell1 272.1599 233.0451 215.6459 Cell2 274.011 232.5328 215.7487 Cell3 267.4294 229.5457 212.8784 Average 271.2001 231.7078 214.7576 88.2

TABLE-US-00006 TABLE 3B Na.sup.+Co.sup.3+ doping, 2.5-4.7 V 0.1C & 2.5-4.45 V 0.2C, 25 C. Retention Capacity 1_st Capacity_2nd after 50 cycle cycle cycles (mAh/g) (mAh/g) % LMNO1226 Cell1 242.9077 202.0012 Cell2 242.392 201.6998 Average 242.6499 201.8505 95.6 Na25Co25 Cell1 248.362 209.063 Cell2 251.7144 211.4612 Average 250.0382 210.2621 93.9 Na375Co375 Cell1 251.4289 213.1349 Cell2 254.5009 212.1146 Average 252.9649 212.6248 93.8

[0055] As can be seen from the results presented above, Na.sup.+Co.sup.3+ dual doping according to the present disclosure increases the capacity.

[0056] FIG. 7 is a graph showing the specific capacity for Na doped, Co doped, and NaCo doped embodiments of the present disclosure compared with embodiments doped with other dopants. As can be seen from FIG. 7, the Na doping, Co doping, and NaCo dual doping of the present disclosure provide excellent results as compared with other doped embodiments, particularly embodiments based on either single doping with any of Cr, Si, and Ca or dual doping with MgCr.

[0057] The foregoing is illustrative of exemplary embodiments and is not to be construed as limiting the disclosure. Although a few exemplary embodiments have been described, those skilled in the art will readily appreciate that many modifications are possible in the above embodiments without materially departing from the disclosure.