Metal/oxygen battery with internal oxygen reservoir
An electrochemical cell in one embodiment includes a negative electrode, a positive electrode spaced apart from the negative electrode, a separator positioned between the negative electrode and the positive electrode; and an active material particle within the positive electrode, the active material particle including an outer shell defining a core with a substantially constant volume and including a form of oxygen, the outer shell substantially impervious to oxygen and pervious to lithium.
1. An electrochemical cell, comprising:
a negative electrode;
a positive electrode spaced apart from the negative electrode;
a separator positioned between the negative electrode and the positive electrode; and
an active material particle within the positive electrode, the active material particle including an outer shell defining a core space and configured such that when the positive electrode is in a fully lithiated state, the core space includes Li 2 O 2 and no electrolyte, and when the positive electrode is in a delithiated state, the core space includes O 2 and no electrolyte.
2. The electrochemical cell of claim 1 , wherein the volume of the core space when the positive electrode is in a fully delithiated state is substantially the same as the volume of the core space when the positive electrode is in a fully lithiated state.
3. The electrochemical cell of claim 2 , wherein the volume of Li 2 O 2 in the core space when the positive electrode is in a fully lithiated state is substantially the same as the volume of the core space.
4. The electrochemical cell of claim 2 , wherein the volume of Li 2 O 2 in the core space when the positive electrode is in a fully lithiated state is less than the volume of the core space.
5. The electrochemical cell of claim 1 , wherein:
the active material particle has a core space diameter;
the outer shell has a thickness; and
the thickness is less than about 10% of the core space diameter.
6. The electrochemical cell of claim 5 , wherein the core space diameter is less than about 10 microns.
7. The electrochemical cell of claim 5 , wherein the core space diameter is less than about 200 nanometers.
8. The electrochemical cell of claim 5 , wherein the thickness is less than about 1 micron.
9. The electrochemical cell of claim 8 , wherein the thickness is less than about 20 nanometers.
10. The electrochemical cell of claim 1 , wherein the outer shell comprises an oxide material.
11. The electrochemical cell of claim 1 , wherein the outer shell comprises a sulfide material.
12. The electrochemical cell of claim 1 , wherein the outer shell is substantially impervious to oxygen and pervious to lithium.
13. The electrochemical cell of claim 1 , wherein the active material particle is one of a plurality of active material particles within the positive electrode, each of the plurality of active material particles including a respective outer shell defining a respective core space and configured such that when the positive electrode is in a fully lithiated state, the respective core space includes Li 2 O 2 and no electrolyte, and when the positive electrode is in a delithiated state, the respective core space includes O 2 and no electrolyte.
14. The electrochemical cell of claim 13 , wherein each of the respective outer shells is substantially spherical.