1. A positive electrode for a rechargeable lithium battery, comprising:
a current collector including pores on a surface thereof; and
a positive active material layer on the current collector and including a positive active material, the positive active material including a lithium metal compound including primary particles and secondary particles including agglomerations of the primary particles,
an average diameter of the pores of the current collector being greater than an average particle diameter (D50) of the primary particles and less than an average particle diameter (D50) of the secondary particles.
2. The positive electrode as claimed in claim 1, wherein the average diameter of the pores is about 0.2 \u03bcm to about 10 \u03bcm.
3. The positive electrode as claimed in claim 1, wherein the pores of the current collector are formed by etching the surface of the current collector.
4. The positive electrode as claimed in claim 1, wherein the average particle diameter (D50) of the primary particles is about 0.2 \u03bcm to about 1 \u03bcm.
5. The positive electrode as claimed in claim 1, wherein the average particle diameter (D50) of the secondary particles is about 1 \u03bcm to about 15 \u03bcm.
6. The positive electrode as claimed in claim 1, wherein the lithium metal compound includes LiFePO4, LiNiaCobMncO2 (0.2\u2266a\u22660.6, 0.2\u2266b\u22660.6, 0.2\u2266c\u22660.6), or a combination thereof.
7. The positive electrode as claimed in claim 1, wherein the positive active material layer further includes activated carbon.
8. The positive electrode as claimed in claim 7, wherein the lithium metal compound is included in an amount of about 55.5 wt % to about 99.5 wt % based on a total amount of the lithium metal compound and the activated carbon.
9. A rechargeable lithium battery, comprising:
the positive electrode as claimed in claim 1;
a negative electrode including a negative active material; and
an electrolyte.
10. The rechargeable lithium battery as claimed in claim 9, wherein the negative active material includes amorphous carbon.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. In a microporous polymer web configured for use as a battery separator, the microporous polymer web including a three-dimensional matrix of polyolefin, a dispersed wettability component, and interconnecting pores that exhibit tortuosity and communicate through the thickness of the microporous polymer web, and the battery separator formed from the microporous polymer web characterized by a porosity, a pore size distribution, and an electrical resistivity when an electrolyte penetrates the interconnecting pores, the improvement comprising:
an electrolyte-soluble pore former distributed throughout the microporous polymer web such that the porosity, pore size distribution, and tortuosity are modified to reduce the electrical resistivity of the battery separator upon dissolution of the electrolyte-soluble pore former.
2. The microporous polymer web of claim 1, in which the electrolyte-soluble pore former includes magnesium hydroxide.
3. The microporous polymer web of claim 1, in which the electrolyte-soluble pore former includes magnesium oxide.
4. The microporous polymer web of claim 1, in which the electrolyte-soluble pore former includes a sulfate of zinc, lithium, aluminum, magnesium, tin, potassium, or sodium; or a carbonate of lithium, magnesium, potassium, or sodium.
5. The microporous polymer web of claim 1, in which the polyolelin comprises ultrahigh molecular weight polyethylene.
6. The microporous polymer web of claim 1, in which the wettability component includes a siliceous filler.
7. The microporous polymer web of claim 6, in which the siliceous filler includes precipitated silica.
8. A method of manufacturing a separator suitable for use in a lead-acid battery, comprising:
forming a microporous polymer web including a three-dimensional polymer matrix of polyolefin, a dispersed wettability component, interconnecting pores exhibiting a tortuosity and communicating through the thickness of the microporous polymer web, and an electrolyte-soluble pore former distributed throughout the microporous polymer web, and the microporous polymer web, in the absence of the electrolyte-soluble pore former, characterized by an electrical resistivity when an electrolyte penetrates the interconnecting pores; and
causing uptake of electrolytic fluid to dissolve the electrolyte-soluble pore former and thereby produce newly generated pores where the electrolyte-soluble pore former resided before dissolution, the newly generated pores modifying the tortuosity of the interconnecting pores to reduce the electrical resistivity of the microporous polymer web.
9. The method of claim 8, in which the causing of uptake of electrolytic fluid is accomplished by:
installing the microporous polymer web in a battery case;
introducing the electrolytic fluid into the battery case so that the microporous polymer web takes up the electrolytic fluid to dissolve the electrolyte-soluble pore former in situ, thereby to form the newly generated pores in locations previously occupied by the dissolved electrolyte-soluble pore former.
10. The method of claim 8, in which the polyolefin web comprises ultrahigh molecular weight polyethylene.
11. The method of claim 8, in which the dispersed wettability component includes a siliceous filler.
12. The method of claim 11, in which the siliceous filler includes precipitated silica.
13. The method of claim 8, in which the electrolyte-soluble pore former includes magnesium hydroxide.
14. The method of claim 8, in which the electrolyte-soluble pore former includes magnesium oxide.
15. The method of claim 8, in which the electrolyte-soluble pore former includes a sulfate of zinc, lithium, aluminum, magnesium, tin, potassium, or sodium; or a carbonate of lithium, magnesium, potassium, or sodium.
16. The method of claim 8, in which the newly generated pores are of sizes that are larger than the sizes of the interconnecting pores.
17. A lead-acid battery including a separator constructed in accordance with the method of claim 8.
18. A lead-acid battery, comprising:
multiple electrodes contained in a case tilled with an electrolytic fluid; and
a battery separator in the form of a microporous polymer web that includes a three-dimensional matrix of polyolefin, interconnecting pores exhibiting a tortuosity and communicating through the thickness of the microporous polymer web, and newly generated pores produced by dissolution of an electrolyte-soluble pore former distributed throughout the microporous polymer web, the microporous polymer web, in the absence of the electrolyte-soluble pore former, characterized by an electrical resistivity, and the newly generated pores in the microporous polymer web decreasing the tortuosity of the interconnecting pores to reduce the electrical resistivity of the battery separator.
19. The battery of claim 18, in which the electrolyte-soluble pore former includes magnesium hydroxide.
20. The battery of claim 18, in which the electrolyte-soluble pore former includes magnesium oxide.
21. The battery of claim 18, in which the electrolyte-soluble pore former includes a sulfate of zinc, lithium, aluminum, magnesium, tin, potassium, or sodium; or a carbonate of lithium, magnesium, potassium, or sodium.
22. The battery of claim 18, in which the newly generated pores are of sizes that are larger than the sizes of the interconnecting pores.