US 2019/0067732 Al  10  Feb.28,2019  [0104]  The graphene oxide (GO) may be obtained by  immersing powders or filaments of a starting graphitic  [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.  [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.  [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:  [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.  [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.  [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).  [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.  [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).  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. 