Silicon oxide based high capacity anode materials for lithium ion batteries
Silicon oxide based materials, including composites with various electrical conductive compositions, are formulated into desirable anodes. The anodes can be effectively combined into lithium ion batteries with high capacity cathode materials. In some formulations, supplemental lithium can be used to stabilize cycling as well as to reduce effects of first cycle irreversible capacity loss. Batteries are described with surprisingly good cycling properties with good specific capacities with respect to both cathode active weights and anode active weights.
1 . A lithium ion battery comprising a positive electrode comprising a lithium metal oxide, a negative electrode, extractable supplemental lithium, an electrolyte comprising lithium ions and from about 5 volume percent to about 18 volume percent of a halogenated carbonate, and a separator between the positive electrode and the negative electrode, wherein the negative electrode has a thickness on a current collector and comprises at least about 80 weight percent of negative electrode active material, from about 2 weight percent to about 15 weight percent of distinct conductive additive, and polymer binder, wherein the negative electrode active material comprises graphite and composite particles comprising carbon and silicon oxide with the structure SiO x , 0.1≤x≤1.5, and wherein a negative electrode capacity is from about 115 percent to about 180 percent of a positive electrode capacity.
2 . The lithium ion battery of claim 1 wherein at least a portion of the extractable supplemental lithium is associated with the negative electrode.
3 . The lithium ion battery of claim 1 wherein the negative electrode active material is preloaded with the extractable supplemental lithium.
4 . The lithium ion battery of claim 1 wherein the extractable supplemental lithium is reversibly associated with the negative electrode.
5 . The lithium ion battery of claim 1 wherein the extractable supplemental lithium comprises elemental lithium.
6 . The lithium ion battery of claim 1 wherein the extractable supplemental lithium corresponds to at least about 2.5% of the negative electrode capacity.
7 . The lithium ion battery of claim 1 wherein the extractable supplemental lithium corresponds to at least about 10% of the negative electrode capacity.
8 . The lithium ion battery of claim 1 wherein the distinct conductive additive comprises nanoscale carbon.
9 . The lithium ion battery of claim 1 wherein the distinct conductive additive comprises carbon nanofibers.
10 . The lithium ion battery of claim 1 wherein the composite particles comprise silicon oxide particles coated with amorphous pyrolytic carbon.
11 . The lithium ion battery of claim 1 wherein the composite particles have volume average particle size of not more than about 8 microns.
12 . The lithium ion battery of claim 1 wherein the distinct conductive additive comprises carbon black and the polymer binder comprises polyimide.
13 . The lithium ion battery of claim 1 wherein the negative electrode active material further comprises elemental silicon.
14 . The lithium ion battery of claim 1 wherein the positive electrode comprises LiMO 2 , where M is one or more metals with an average oxidation state of +3.
15 . The lithium ion battery of claim 1 wherein the positive electrode comprises lithium metal oxide represented by the formula Li 1+b Ni α Mn β Co γ A δ O 2-z F z , where b ranges from about 0.01 to about 0.3, a ranges from about 0 to about 0.4, β ranges from about 0.2 to about 0.65, γ ranges from 0 to about 0.46, δ ranges from 0 to about 0.15 and z ranges from 0 to about 0.2 with the proviso that both α and γ are not zero, and where A is Mg, Sr, Ba, Cd, Zn, Al, Ga, B, Zr, Ti, Ca, Ce, Y, Nb, Cr, Fe, V, Li or combinations thereof.
16 . The lithium ion battery of claim 1 wherein the halogenated carbonate comprises fluoroethylene carbonate.
17 . The lithium ion battery of claim 1 wherein the negative electrode has a specific discharge capacity of at least about 700 mAh/g at a rate of C/3 based on negative electrode active material mass.
18 . The lithium ion battery of claim 1 wherein a battery discharge capacity decreases by no more than about 15 percent at a 50th discharge cycle relative to a 7th discharge cycle when discharged at a rate of C/3 from the 7th discharge cycle to the 50th discharge cycle.
19 . The lithium ion battery of claim 1 wherein after 50 charge-discharge cycles between 4.5V and 1.0V, the battery exhibits at least about 750 mAh/g discharge capacity from the negative electrode and at least about 150 mAh/g discharge capacity from the positive electrode at a rate of C/3.
20 . The lithium ion battery of claim 1 wherein the polymer binder has an elongation of at least about 50% without tearing.
21 . The lithium ion battery of claim 20 wherein the polymer binder has a tensile strength of at least about 100 MPa.
22 . The lithium ion battery of claim 1 wherein the negative electrode active material comprises from about 5 wt % to about 30 wt % graphite.
23 . The lithium ion battery of claim 1 wherein the distinct conductive additive comprises carbon black or acetylene black.
24 . The lithium ion battery of claim 1 wherein the polymer binder comprises a mixture of polyimide and one or more of sodium carboxy methyl cellulose (CMC), polyvinylidine fluoride (PVDF), polyethylene oxide, polyethylene, polypropylene, polytetrafluoroethylene, polyacrylates, and rubber.
25 . The lithium ion battery of claim 24 wherein the rubber comprises ethylene-propylene-diene monomer (EPDM) rubber and/or styrene butadiene rubber (SBR).
26 . The lithium ion battery of claim 1 wherein the polymer binder comprises a polyacrylate.