Process for producing carbon anode compositions for lithium ion batteries
View Patent ↗This invention provides a process for producing a lithium secondary battery. The process comprises: (a) providing a positive electrode; (b) providing a negative electrode comprising a carbonaceous material capable of absorbing and desorbing lithium ions, wherein the carbonaceous material is obtained by chemically or electrochemically treating a laminar graphite material to form a graphite crystal structure having an interplanar spacing d 002 of at least 0.400 nm as determined from a (002) reflection peak in powder X-ray diffraction; and (c) providing a non-aqueous electrolyte disposed between the negative electrode and the positive electrode to form the battery structure. This larger interplanar spacing (greater than 0.400 nm, preferably no less than 0.55 nm) implies a larger interstitial space between two graphene planes to accommodate a greater amount of lithium. The resulting battery exhibits an exceptionally high specific capacity, an excellent reversible capacity, and a long cycle life.
1. A process for producing a lithium secondary battery, said process comprising:
(a) providing a positive electrode;
(b) providing a negative electrode comprising a graphite oxide or graphite fluoride capable of absorbing and desorbing lithium ions, wherein said graphite oxide or graphite fluoride is obtained by chemically or electrochemically treating a laminar graphite material to form a graphite crystal structure having an interplanar spacing d 002 of at least 0.55 nm as determined from a (002) reflection peak in powder X-ray diffraction; and
(c) providing a non-aqueous electrolyte disposed between said negative electrode and said positive electrode to form said battery.
2. The process as defined in claim 1 , wherein said laminar graphite is selected from natural graphite, synthetic graphite, highly oriented pyrolytic graphite, graphite fiber, carbon fiber, carbon nano-fiber, graphitic nano-fiber, spherical graphite or graphite globule, meso-phase micro-bead, carbon nano-tube, or a combination thereof.
3. The process as defined in claim 1 , wherein said chemical or electrochemical treatment comprises a step of chemically or electrochemically intercalating said laminar graphite material.
4. The process as defined in claim 1 , wherein said chemical or electrochemical treatment comprises a step of chemically or electrochemically oxidizing said laminar graphite material or reacting said laminar graphite with a halogen element or halogen compound.
5. The process as defined in claim 1 , wherein step (c) comprises introducing said electrolyte into pores of a separator layer disposed between said anode and said cathode.
6. The process according to claim 1 , wherein said positive electrode comprises lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, or a combination thereof.
7. The process as defined in claim 1 , wherein said step of chemically or electrochemically treating a laminar graphite material is followed by dispersing said treated laminar graphite material in an amorphous carbon or polymeric carbon phase.
8. The process of claim 7 , wherein said amorphous carbon phase is obtained from chemical vapor deposition, chemical vapor infiltration, or pyrolyzation of an organic precursor.
9. The process as defined in claim 1 , wherein said step of chemically or electrochemically treating a laminar graphite material is followed by dispersing said treated laminar graphite material in an electrically conductive binder material.
10. The process as defined in claim 9 , wherein said electrically conductive binder material comprises coal tar pitch, petroleum pitch, meso-phase pitch, coke, activated carbon, carbon black, a conjugate chain polymer, or a derivative thereof.
11. The process as defined in claim 1 , wherein said step of chemically or electrochemically treating a laminar graphite material is followed by dispersing said treated laminar graphite material in a non-conductive binder material.
12. The process as defined in claim 11 , wherein said binder material is selected from poly (vinylidene fluoride), poly(tetra-fluoro-ethylene), polyvinyl fluoride, ethylene-propylene-diene copolymer, styrene-butadiene rubber, a copolymer thereof, a derivative thereof, or a combination thereof.
13. The process of claim 1 , wherein said graphite oxide or graphite fluoride provides a specific capacity of no less than 500 mAh/g.
14. The process as defined in claim 1 , wherein said graphite oxide or graphite fluoride provides a specific capacity of no less than 650 mAh/g.
15. The process as defined in claim 1 , wherein said graphite oxide or graphite fluoride provides a specific capacity of no less than 750 mAh/g.