Battery life by controlling the voltage window of the negative electrode
In an example of a method for improving a life cycle of a battery containing a lithium-silicon negative electrode, the battery is provided. The battery includes a positive electrode; the lithium-silicon negative electrode, which has at least 10% of its capacity attributed to a silicon-based active material; a separator positioned between the positive and negative electrodes; and an electrolyte. The battery is operated within a voltage potential window ranging from about 0.7 V and about 0.07 V versus a lithium reference electrode.
1. A method for improving a life cycle of a battery containing a lithium-silicon thin-film negative electrode, the method comprising:
providing the battery, including:
a positive electrode;
the lithium-silicon thin-film negative electrode having at least 10% of its capacity attributed to a silicon-based active material and a thickness of less than about 50 μm;
a separator positioned between the positive and negative electrodes; and
an electrolyte; and
operating the battery within a voltage potential window ranging from about 0.7 V and about 0.07 V versus a lithium reference electrode so that a stress amplitude of the lithium-silicon thin-film negative electrode is maintained from about −0.5 GPa to about 0.3 GPa during the operating of the battery.
2. The method as defined in claim 1 wherein an areal capacity ratio of negative to positive electrodes (N/P ratio) ranges from 1.025 to 3.
3. The method as defined in claim 1 , further comprising controlling the voltage potential window to be within a range from about 0.637 V and about 0.1871 V versus the lithium reference electrode.
4. The method as defined in claim 1 , further comprising controlling the voltage potential window to be within a range from about 0.5526 V and about 0.1331 V versus the lithium reference electrode.
5. The method as defined in claim 1 , further comprising controlling the voltage potential window to be within a range from about 0.4650 V and about 0.0763 V versus the lithium reference electrode.
6. The method as defined in claim 1 wherein:
the lithium-silicon negative electrode is a lithium-silicon thin-film negative electrode; and
a capacity of the lithium-silicon negative electrode is about 1.0 mAh/cm 2 or greater over at least 10 cycles.
7. The method as defined in claim 1 wherein the stress amplitude of the lithium-silicon negative electrode is maintained at a negative GPa during the operation of the battery.
8. The method as defined in claim 1 wherein the silicon-based active material is silicon or a silicon alloy.
9. The method as defined in claim 1 wherein the lithium-silicon negative electrode is a thin film of silicon having a thickness ranging from about 50 nm to about 50 μm.
10. A method for conditioning a negative electrode, the method comprising:
incorporating a silicon film having a thickness ranging from about 50 nm to about 50 μm into a silicon-lithium battery as a negative electrode, such that a separator is positioned between the silicon film and a positive electrode;
soaking the silicon-lithium battery in an electrolyte; and
operating the lithium-silicon battery within a voltage potential window ranging from about 0.7 V and about 0.07 V versus a lithium reference electrode, thereby conditioning the negative electrode with a compressive stress state;
wherein the negative electrode retains the compressive stress state so that a stress amplitude of the lithium-silicon negative electrode is maintained from about −0.5 GPa to about 0.3 GPa during subsequent battery cycles operating within the voltage potential window.
11. The method as defined in claim 10 , wherein an areal capacity ratio of negative to positive electrodes (N/P ratio) ranges from 1.025 to 3.
12. The method as defined in claim 10 , wherein the voltage potential window is within a range from about 0.637 V and about 0.1871 V versus the lithium reference electrode.
13. The method as defined in claim 10 , wherein the voltage potential window is within a range from about 0.5526 V and about 0.1331 V versus the lithium reference electrode.
14. The method as defined in claim 10 , wherein the voltage potential window is within a range from about 0.4650 V and about 0.0763 V versus the lithium reference electrode.
15. The method as defined in claim 10 , wherein a capacity of the lithium-silicon negative electrode is about 1.0 mAh/cm 2 or greater over at least 10 cycles.
16. The method as defined in claim 10 , wherein the stress amplitude of the lithium-silicon negative electrode is maintained at a negative GPa during subsequent battery cycles operating within the voltage potential window.
17. The method as defined in claim 10 , wherein the silicon-based active material is silicon or a silicon alloy.