mesa-phase pitch, mesa-carbon micro-bead, soft carbon, hard carbon, coke, carbon fiber, carbon nano-fiber, carbon nano-tube, or a combination thereof. Graphene materials are also a good conductive additive for both the anode and cathode active materials of an alkali metal battery. 

[0096] The constituent graphene planes of a graphite crys› tallite in a natural or artificial graphite particle can be exfoliated and extracted or isolated to obtain individual graphene sheets of hexagonal carbon atoms, which are single-atom thick, provided the inter-planar van der Waals forces can be overcome. An isolated, individual graphene plane of carbon atoms is commonly referred to as single› layer graphene. A stack of multiple graphene planes bonded through van der Waals forces in the thickness direction with an inter-graphene plane spacing of approximately 0.3354 nm is commonly referred to as a multi-layer graphene. A multi-layer graphene platelet has up to 300 layers of gra› phene planes (<100 nm in thickness), but more typically up to 30 graphene planes (<10 nm in thickness), even more typically up to 20 graphene planes ( <7 nm in thickness), and most typically up to 10 graphene planes ( commonly referred to as few-layer graphene in scientific community). Single› layer graphene and multi-layer graphene sheets are collec› tively called "nano graphene platelets" (NGPs ). Graphene sheets/platelets (collectively, NGPs) are a new class of carbon nano material (a 2-D nano carbon) that is distinct from the 0-D fullerene, the 1-D CNT or CNF, and the 3-D graphite. For the purpose of defining the claims and as is commonly understood in the art, a graphene material (iso› lated graphene sheets) is not (and does not include) a carbon nanotube (CNT) or a carbon nano-fiber (CNF). 

[0097] In one process, graphene materials are obtained by intercalating natural graphite particles with a strong acid and/or an oxidizing agent to obtain a graphite intercalation compound (GIC) or graphite oxide (GO), as illustrated in FIG. 2(A) and FIG. 2(8) (schematic drawings). The pres› ence of chemical species or functional groups in the inter› stitial spaces between graphene planes in a GIC or GO serves to increase the inter-graphene spacing ( d$_{002}$ , as deter› mined by X-ray diffraction), thereby significantly reducing the van der Waals forces that otherwise hold graphene planes together along the c-axis direction. The GIC or GO is most often produced by immersing natural graphite powder (100 in FIG. 2(8)) in a mixture of sulfuric acid, nitric acid (an oxidizing agent), and another oxidizing agent (e.g. potas› sium permanganate or sodium perchlorate). The resulting GIC (102) is actually some type of graphite oxide (GO) particles if an oxidizing agent is present during the interca› lation procedure. This GIC or GO is then repeatedly washed and rinsed in water to remove excess acids, resulting in a graphite oxide suspension or dispersion, which contains discrete and visually discernible graphite oxide particles dispersed in water. In order to produce graphene materials, one can follow one of the two processing routes after this rinsing step, briefly described below: 

[0098] Route 1 involves removing water from the suspen› sion to obtain "expandable graphite," which is essentially a mass of dried GIC or dried graphite oxide particles. Upon exposure of expandable graphite to a temperature in the range of typically 800-1,050° C. for approximately 30 seconds to 2 minutes, the GIC undergoes a rapid volume expansion by a factor of 30-300 to form "graphite worms" (104), which are each a collection of exfoliated, but largely un-separated graphite flakes that remain interconnected. 

[0099] In Route IA, these graphite worms (exfoliated graphite or "networks of interconnected/non-separated graphite flakes") can be re-compressed to obtain flexible graphite sheets or foils (106) that typically have a thickness in the range of 0.1 mm (100 µm)-0.5 mm (500 µm). Alternatively, one may choose to use a low-intensity air mill or shearing machine to simply break up the graphite worms for the purpose of producing the so-called "expanded graph› ite flakes" (108) which contain mostly graphite flakes or platelets thicker than 100 nm (hence, not a nano material by definition). 

[0100] In Route 18, the exfoliated graphite is subjected to high-intensity mechanical shearing (e.g. using an ultrasoni› cator, high-shear mixer, high-intensity air jet mill, or high› energy ball mill) to form separated single-layer and multi› layer graphene sheets (collectively called NGPs, 112), as disclosed in our U.S. application Ser. No. 10/858,814 (Jun. 3, 2004). Single-layer graphene can be as thin as 0.34 nm, while multi-layer graphene can have a thickness up to 100 nm, but more typically less than 10 nm ( commonly referred to as few-layer graphene). Multiple graphene sheets or platelets may be made into a sheet of NGP paper using a paper-making process. This sheet of NGP paper is an example of the porous graphene structure layer utilized in the presently invented process. 

[0101] Route 2 entails ultrasonicating the graphite oxide suspension (e.g. graphite oxide particles dispersed in water) for the purpose of separating/isolating individual graphene oxide sheets from graphite oxide particles. This is based on the notion that the inter-graphene plane separation bas been increased from 0.3354 nm in natural graphite to 0.6-1.1 nm in highly oxidized graphite oxide, significantly weakening the van der Waals forces that hold neighboring planes together. Ultrasonic power can be sufficient to further sepa› rate graphene plane sheets to form fully separated, isolated, or discrete graphene oxide (GO) sheets. These graphene oxide sheets can then be chemically or thermally reduced to obtain "reduced graphene oxides" (RGO) typically having an oxygen content of 0.001%-10% by weight, more typi› cally 0.01 %-5% by weight, most typically and preferably less than 2% by weight of oxygen. 

[0102] For the purpose of defining the claims of the instant application, NGPs or graphene materials include discrete sheets/platelets of single-layer and multi-layer (typically less than 10 layers) pristine graphene, graphene oxide, reduced graphene oxide (RGO), graphene fluoride, graphene chloride, graphene bromide, graphene iodide, hydrogenated graphene, nitrogenated graphene, chemically functionalized graphene, doped graphene (e.g. doped by B or N). Pristine graphene has essentially 0% oxygen. RGO typically has an oxygen content of 0.001 %-5% by weight. Graphene oxide (including RGO) can have 0.001 %-50% by weight of oxy› gen. Other than pristine graphene, all the graphene materials have 0.001 %-50% by weight of non-carbon elements ( e.g. 0, H, N, B, F, Cl, Br, I, etc.). These materials are herein referred to as non-pristine graphene materials. 

[0103] Pristine graphene, in smaller discrete graphene sheets (typically 0.3 µm to 10 µm), may be produced by direct ultrasonication (also known as liquid phase exfolia› tion or production) or supercritical fluid exfoliation of graphite particles. These processes are well-known in the art. 

[0104] The graphene oxide (GO) may be obtained by immersing powders or filaments of a starting graphitic 

