Lithium-containing electrochemical cells, electrochemical systems, and related methods
Electrochemical cells and electrochemical systems containing lithium (e.g., lithium metal) are generally described.
1 . An electrochemical system, the system comprising:
an electrochemical cell, comprising:
a first electrode comprising a base electrode material layer comprising a first active electrode species, wherein the first active electrode species comprises lithium metal;
a second electrode comprising a second active electrode species, wherein the second active electrode species comprises nickel, cobalt, and manganese, and wherein the second electrode comprises a binder comprising a fluorinated compound and conductive carbon;
a separator; and
an electrolyte, wherein the electrolyte comprises:
a first solvent comprising a fluorinated carbonate;
a second solvent comprising a carbonate, wherein a ratio of the fluorinated carbonate to the carbonate is greater than or equal to 5:95 and less than or equal to 95:1; and
a lithium salt,
wherein an anisotropic force is applied to the electrochemical cell, the anisotropic force comprising a component normal to a surface of the first electrode, and wherein the component normal defines a pressure of at least about 4.9 N/cm 2 .
2 . A method of operating an electrochemical system, the method comprising:
in an electrochemical cell, comprising:
a first electrode comprising a base electrode material layer comprising a first active electrode species, wherein the first active electrode species comprises lithium metal;
a second electrode comprising:
a second active electrode species, wherein the second active electrode species comprises lithium, nickel, cobalt, and manganese; wherein the second electrode comprises a binder comprising a fluorinated compound and conductive carbon; and
an electrolyte, wherein the electrolyte comprises:
a first solvent comprising a fluorinated carbonate, a second solvent comprising a carbonate, wherein a ratio of the fluorinated carbonate to the carbonate is greater than 1:1 and less than or equal to 10:1; and
a lithium salt,
performing the steps of:
charging the electrochemical cell at a charging rate over a first state of charge range having breadth of at least 2%,
discharging the electrochemical cell at a discharging rate over a second state of charge range having a breadth of at least 2%,
wherein the discharging rate is at least 2 times the charging rate.
3 . An electrochemical system, the system comprising:
an electrochemical cell, comprising:
a first electrode comprising a base electrode material layer comprising a first active electrode species, wherein the first active electrode species comprises lithium metal, and where the first electrode comprises a protective layer adjacent to the base electrode material layer, wherein the protective layer comprises pores and has a thickness of less than 5 microns;
a second electrode comprising a second active electrode species, wherein the second active electrode species comprises lithium, nickel, cobalt, and manganese;
a separator; and
an electrolyte, wherein the electrolyte comprises:
a first solvent comprising a fluorinated carbonate;
a second solvent comprising a carbonate, and
a lithium salt,
wherein an anisotropic force is applied to the electrochemical cell,
the anisotropic force comprising a component normal to a surface of the first electrode, and wherein the component defines a pressure of at least about 4.9 N/cm 2 .
4 . The system of claim 1 , further comprising a protective layer, and wherein the protective layer comprises a ceramic material.
5 . The system of claim 1 , further comprising a protective layer, and wherein the protective layer comprises a plurality of particles.
6 . The system of claim 1 , further comprising a protective layer, and wherein the protective layer comprises ionically conductive and ionically non-ionically conductive particles.
7 . The system of claim 1 , further comprising a protective layer, and wherein the protective layer comprises a compound comprising Li 22 .
8 . The system of claim 5 , wherein at least a portion of the plurality of particles are fused to one another such that at least a portion of an original surface of the particles can no longer be discerned in the portion of the plurality of particles fused to one another.
9 . The system of claim 8 , wherein a polymeric material is present in at least a portion of spaces between the fused particles.
10 . The system of claim 5 , wherein at least a portion of the plurality of particles of the protective layer are embedded in the lithium of the first electrode.
11 . The system of claim 1 , further comprising a protective layer, and wherein the protective layer comprises a compound of formula (I): Li x M y Q w P z S u X t (I) wherein: M is Fe Q is absent or selected from the group consisting of Cr, B, Sn, Si, Ta, Nb, V, P, Fe, Ga, Al, As, and combinations thereof, and wherein Q, when present, is different than M, X is absent or selected from the group consisting of halide and pseudohalide, where x is 8-22, y is 0.1-3, w is 0-3, z is 0.1-3, u is 7-20, and t is 0-8.
12 . The system of claim 1 , further comprising a protective layer, and wherein the protective layer comprises a compound of formula (B): Li 2x S x+w+5z M y P 2z (I) wherein: M is selected from the group consisting of Lanthanides, Group 3, Group 4, Group 5, Group 6, Group 7, Group 8, Group 9, Group 12, Group 13, and Group 14 atoms, and combinations thereof; x is 8-16, y is 0.1-6, w is 0.1-15, and z is 0.1-3.
13 . The system of claim 1 , wherein the second active electrode species comprises a lithium intercalation compound having a nickel content of greater than or equal to 70 mol % relative to other transition metals of the second active electrode species.
14 . The system of claim 1 , wherein the lithium salt comprises LiPF 6 .
15 . The system of claim 1 , wherein the lithium salt comprises LiBOB.
16 . The system of claim 1 , wherein the lithium salt comprises LiTOP.
17 . The system of claim 1 , further comprising a release layer adjacent to the first electrode and/or the second electrode.
18 . The system of claim 1 , wherein the anisotropic force is applied to the electrochemical cell during at least one period of time during charge and/or discharge of the electrochemical cell.
19 . The system of claim 1 , further comprising a solid electrolyte interphase layer disposed between the first electrode and the electrolyte, wherein the solid electrolyte interphase layer comprises an inorganic material comprising LiF and Li 2 CO 3 .
20 . The system of claim 19 , wherein a first ratio of fluorine atoms to oxygen atoms adjacent the electrolyte is higher than a second ratio of fluorine atoms to oxygen atoms adjacent the anode in the solid electrolyte interphase layer.