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AssigneeZenlabs Energy, Inc.
InventorsYogesh Kumar Anguchamy, Haixia Deng, Yongbong Han, Charan Masarapu, Sujeet Kumar, Herman A. Lopez
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Composite silicon based materials are described that are effective active materials for lithium ion batteries. The composite materials comprise processed, e.g., high energy mechanically milled, silicon suboxide and graphitic carbon in which at least a portion of the graphitic carbon is exfoliated into graphene sheets. The composite materials have a relatively large surface area, a high specific capacity against lithium, and good cycling with lithium metal oxide cathode materials. The composite materials can be effectively formed with a two step high energy mechanical milling process. In the first milling process, silicon suboxide can be milled to form processed silicon suboxide, which may or may not exhibit crystalline silicon x-ray diffraction. In the second milling step, the processed silicon suboxide is milled with graphitic carbon. Composite materials with a high specific capacity and good cycling can be obtained in particular with balancing of the processing conditions.
A composite material comprising processed silicon suboxide and graphitic carbon wherein at least a portion of the graphitic carbon is in graphene sheets, wherein the composite material has a BET surface area from about 5 m2/g to about 35 m2/g and a discharge capacity of at least about 800 mAh/g at a rate of C/20 discharged from 1.5V to 0.005V against lithium metal.
A composite material comprising processed silicon suboxide and from about 0.5 weight percent to 20 weight percent graphitic carbon, wherein at least a portion of the graphitic carbon is in graphene sheets, and wherein the material has a discharge capacity of at least about 800 mAh/g at a rate of C/20 discharged from 1.5V to 0.005V against lithium metal and wherein the material has a 50th cycle discharge capacity that is at least about 87% of the 5th cycle discharge capacity when cycled against lithium from 1.5V to 0.005V at a discharge rate of C/3.
A method for forming a composite material comprising processed silicon oxide and graphitic carbon at least a portion of which is in graphene sheets, the method comprising:
A lithium ion secondary battery comprising a positive electrode, a negative electrode, a separator between the positive electrode comprising a lithium metal oxide and the negative electrode and an electrolyte comprising lithium ions,
Dependencies are inferred from the claim text.