Additives for electrochemical cells
Articles and methods including additives in electrochemical cells, are generally provided. As described herein, such electrochemical cells may comprise an anode, a cathode, an electrolyte, and optionally a separator. In some embodiments, at least one of the anode, the cathode, the electrolyte, and/or the optional separator may comprise an additive and/or additive precursor. For instance, in some cases, the electrochemical cell comprises an electrolyte and an additive and/or additive precursor that is soluble with and/or is present in the electrolyte. In some embodiments, the additive precursor comprises a disulfide bond. In certain embodiments, the additive is a carbon disulfide salt. In some cases, the electrolyte may comprise a nitrate.
1. An electrochemical cell, comprising:
a first electrode, wherein the first electrode comprises an alkali metal;
a protective layer comprising a ceramic and/or a glass disposed on the first electrode;
a second electrode;
a separator; and
an electrolyte, wherein:
the electrolyte comprises a fluorinated ether,
the electrolyte comprises an unfluorinated carbonate; and
the electrolyte comprises a fluorinated carbonate.
2. An electrochemical cell as in claim 1 , wherein the alkali metal is lithium metal.
3. An electrochemical cell as in claim 1 , wherein the second electrode is a lithium-intercalation cathode.
4. An electrochemical cell as in claim 3 , wherein the lithium-intercalation cathode comprises Li x CoO 2 , Li x NiO 2 , Li x MnO 2 , Li x Mn 2 O 4 , Li x FePO 4 , Li x CoPO 4 , Li x MnPO 4 , and Li x NiPO 4 , where (0<x≤1), and/or LiNi x Mn y Co z O 2 where (x+y+z=1).
5. An electrochemical cell as in claim 1 , wherein the electrolyte comprises LiPF 6 .
6. An electrochemical cell as in claim 1 , wherein the electrolyte comprises LiBF 4 .
7. An electrochemical cell as in claim 1 , wherein the electrolyte comprises a sulfonimide salt.
8. An electrochemical cell as in claim 7 , wherein the sulfonimide salt is lithium bis(trifluoromethane) sulfonimide.
9. An electrochemical cell as in claim 1 , wherein the unfluorinated carbonate is a linear unfluorinated carbonate.
10. An electrochemical cell as in claim 9 , wherein the unfluorinated linear carbonate is dimethyl carbonate.
11. An electrochemical cell as in claim 1 , wherein the fluorinated carbonate is a cyclic fluorinated carbonate.
12. An electrochemical cell as in claim 11 , wherein the cyclic fluorinated carbonate is fluoroethylene carbonate.
13. An electrochemical cell as in claim 1 , wherein the fluorinated ether is a linear fluorinated ether.
14. An electrochemical cell as in claim 13 , wherein the linear fluorinated ether is a fluorinated diethyl ether.
15. An electrochemical cell as in claim 1 , wherein the protective layer is an ion-conductive layer that is non-polymeric.
16. An electrochemical cell as in claim 7 , wherein the sulfonimide salt is LiN(SO 2 F) 2 .