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Combinations of materials are described in which high energy density active materials for negative electrodes of lithium ion batteries. In general, metal alloy/intermetallic compositions can provide the high energy density. These materials can have moderate volume changes upon cycling in a lithium i

Combinations of materials are described in which high energy density active materials for negative electrodes of lithium ion batteries. In general, metal alloy/intermetallic compositions can provide the high energy density. These materials can have moderate volume changes upon cycling in a lithium ion battery. The volume changes can be accommodated with less degradation upon cycling through the combination with highly porous electrically conductive materials, such as highly porous carbon and/or foamed current collectors. Whether or not combined with a highly porous electrically conductive material, metal alloy/intermetallic compositions with an average particle size of no more than a micron can be advantageously used in the negative electrodes to improve cycling properties.

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1. A lithium ion battery comprising a positive electrode, a negative electrode, a separator between the positive electrode and the negative electrode and an electrolyte comprising lithium ions, wherein the negative electrode comprises a composite composition formed through milling of metal and/or me

1. A lithium ion battery comprising a positive electrode, a negative electrode, a separator between the positive electrode and the negative electrode and an electrolyte comprising lithium ions, wherein the negative electrode comprises a composite composition formed through milling of metal and/or metal alloy/intermetallic particles and from about 12 to about 65 weight % of high surface area carbon particles that have submicron particle size, andwherein the positive electrode comprises an electroactive material having discharge capacity at a 10th discharge cycle of at least 240 mAh/g at room temperature at a discharge rate of C/3 when discharged from 4.6 volts to 2.0 volts. 2. The lithium ion battery of claim 1 wherein the high surface area carbon particles have a Brunauer-Emmett-Teller (BET) surface area from about 255 to about 3500 m2/g. 3. The lithium ion battery of claim 1 wherein the high surface area carbon particles comprise activated carbon, mesoporous carbon, or combination thereof. 4. The lithium ion battery of claim 1 wherein the metal and/or metal alloy/intermetallic particles have an average particle size of no more than 1 micron. 5. The lithium ion battery of claim 1 wherein the metal and/or metal alloy/intermetallic particles comprise elemental silicon. 6. The lithium ion battery of claim 1 wherein the high surface area carbon particles have a Brunauer-Emmett-Teller (BET) surface area of at least about 250 m2/g. 7. The lithium ion battery of claim 1 wherein the composite comprises at least about 65 weight percent metal and/or metal alloy/intermetallic. 8. The lithium ion battery of claim 1 wherein the metal and/or metal alloy/intermetallic particles are amorphous. 9. The lithium ion battery of claim 1 wherein the metal and/or metal alloy/intermetallic particles have an average particle size of no more than 250 nm 10. The lithium ion battery of claim 1 wherein the metal and/or metal alloy/intermetallic particles comprises a tin-copper alloy or an alloy of copper, tin and one or more additional metals, tin, or combination thereof. 11. The lithium ion battery of claim 1 wherein the metal alloy/intermetallic particles comprises a composition having a formula SixSnqMyCz, where (q +x)>2y+z, q>=0, z>=0 and M is a metal selected from manganese, molybdenum, niobium, tungsten, tantalum, iron, copper, titanium, vanadium, chromium, nickel, cobalt, zirconium, yttrium and combinations thereof having at least about 40 weight percent and about 80 atomic percent Si as an amorphous Si phase, a nanocrystalline metal silicide phase, a silicon carbide phase when z>0, and an amorphous Sn phase when q>0. 12. The lithium ion battery of claim 1 wherein the metal alloy/intermetallic particles comprises a composition having a formula Sn-E-M, where E is boron (B), carbon (C), aluminum (Al), phosphorous (P) or a combination thereof ranging from 9.8 weight percent to 49 weight percent, and M is a metal selected from silicon, magnesium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, zirconium, niobium, molybdenum, silver, indium, cerium, hafnium, tantalum, tungsten, bismuth and combinations thereof. 13. The lithium ion battery of claim 1 wherein the electroactive material of the positive electrode has a 10th cycle specific discharge capacity of at least 235 mAh/g at room temperature and a tap density of at least 1.8 g/mL, wherein the specific discharge capacity is determined at a discharge rate of C/3 when discharged from 4.6 volts to 2.0 volts. 14. The lithium ion battery of claim 1 wherein the negative electrode further comprises a foamed current collector impregnating the electroactive negative electrode composite and lacks a foil current collector or a grid current collector separate from the foamed current collector. 15. The lithium ion battery of claim 14 wherein the foamed current collector comprises carbon, nickel, titanium, aluminum, stainless steel, or a combination thereof. 16. A lithium ion battery comprising a positive electrode, a negative electrode, a separator between the positive electrode and the negative electrode, and an electrolyte comprising lithium ions, wherein the negative electrode comprises metal and/or metal alloy/intennetallic particles, high surface area carbon particles, and lithium titanate particles having an average particle size of no more than 1 micron forming an electroactive negative electrode composite, andwherein the positive electrode comprises an electroactive material having discharge capacity at a 10th discharge cycle of at least 240 mAh/g at room temperature at a discharge rate of C/3 when discharged from 4.6 volts to 2.0 volts. 17. The lithium ion battery of claim 16 wherein the metal alloy/intermetallic particles and the lithium titanate particles each have an average particle size of no more than 250 nm. 18. The lithium ion battery of claim 16 wherein the lithium titanate comprises from about 1 weight percent to about 45 weight percent relative to the combined weight of the metal alloy/intermetallic particles and the lithium titanate. 19. The lithium ion battery of claim 16 wherein the high surface area carbon particles have a Brunauer-Emmett-Teller (BET) surface area from about 255 to about 3500 m2/g. 20. The lithium ion battery of claim 16 wherein the high surface area carbon particles comprise activated carbon, mesoporous carbon, or combination thereof. 21. The lithium ion battery of claim 16 wherein the metal and/or metal alloy/intennetallic particles comprise elemental silicon. 22. The lithium ion battery of claim 16 wherein the metal and/or metal alloy/intermetallic particles comprises a tin-copper alloy or an alloy of copper, tin and one or more additional metals, tin, or combination thereof. 23. The lithium ion battery of claim 16 wherein the metal alloy/intermetallic particles comprises a composition having a formula SixSnqMyCz, where (q+x)>2y+z, q>=0, z>=0 and M is a metal selected from manganese, molybdenum, niobium, tungsten, tantalum, iron, copper, titanium, vanadium, chromium, nickel, cobalt, zirconium, yttrium and combinations thereof having at least about 40 weight percent and about 80 atomic percent Si as an amorphous Si phase, a nanocrystalline metal silicide phase, a silicon carbide phase when z>0, and an amorphous Sn phase when q>0. 24. The lithium ion battery of claim 16 wherein the metal alloy/intennetallic particles comprises a composition having a formula Sn-E-M, where E is boron (B), carbon (C), aluminum (Al), phosphorous (P) or a combination thereof ranging from 9.8 weight percent to 49 weight percent, and M is a metal selected from silicon, magnesium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, zirconium, niobium, molybdenum, silver, indium, cerium, hafnium, tantalum, tungsten, bismuth and combinations thereof. 25. The lithium ion battery of claim 16 wherein the electroactive material of the positive electrode has a 10th cycle specific discharge capacity of at least 235 mAh/g at room temperature and a tap density of at least 1.8 g/mL, wherein the specific discharge capacity is determined at a discharge rate of C/3 when discharged from 4.6 volts to 2.0 volts. 26. The lithium ion battery of claim 16 wherein the negative electrode further comprises a foamed current collector impregnating the electroactive negative electrode composite and lacks a foil current collector or a grid current collector separate from the foamed current collector, wherein the foamed current collector comprises carbon, nickel, titanium, aluminum, stainless steel, or a combination thereof.