US 2019/0067732 Al  15  Feb.28,2019  Example  1:  Preparation of Graphene Oxide (GO)  and Reduced Graphene Oxide (RGO) Nano Sheets  from Natural Graphite Powder  [0150]  Natural graphite from Huadong Graphite Co.  (Qingdao, China) was used as the starting material. GO was  obtained by following the well-known modified Hummers  [0145]  Common cations of room temperature ionic liquids  (RTILs) include, but not limited to, tetraalkylammonium,  di-,  tri-,  and  tetra-alkylimidazolium,  alkylpyridinium,  [0149]  In what follows, we provide examples for a large  number of different types of anode active materials, cathode  active materials, and conductive fillers to illustrate the best  mode of practicing the instant invention. Theses illustrative  examples and other portions of instant specification and  drawings, separately or in combinations, are more than  adequate to enable a person of ordinary skill in the art to  practice the instant invention. However, these examples  should not be construed as limiting the scope of instant  invention.  [0144]  Ionic liquids are basically composed of organic  ions that come in an essentially unlimited number of struc› tural variations owing to the preparation ease of a large  variety of their components. Thus, various kinds of salts can  be used to design the ionic liquid that has the desired  properties for a given application. These include, among  others, imidazolium, pyrrolidinium and quaternary ammo› nium salts as cations and bis(trifluoromethanesulphonyl)  imide, bis(fluorosulphonyl)imide, and hexafluorophosphate  as anions. Based on their compositions, ionic liquids come  in different classes that basically include aprotic, protic and  zwitterionic types, each one suitable for a specific applica› tion.  [0143]  A typical and well-known ionic liquid is formed by  the combination of a l-ethyl-3-methylimidazolium (EMI)  cation  and  an  N,N-bis(trifluoromethane)sulphonamide  (TFSI) anion. This combination gives a fluid with an ionic  conductivity comparable to many organic electrolyte solu› tions and a low decomposition propensity and low vapor  pressure up to -300-400°  C. This implies a generally low  volatility and non-flammability and, hence, a much safer  electrolyte for batteries.  [0148]  In certain embodiments, the ion-conducting poly› mer may be selected from the group consisting of poly  (perfluoro sulfonic acid), sulfonated polytetrafluoroethyl› ene,  sulfonated  perfluoroalkoxy  derivatives  of  polytetrafluoroethylene, sulfonated polysulfone, sulfonated  poly( ether ketone), sulfonated poly ( ether ether ketone),  sulfonated polystyrene, sulfonated polyimide, sulfonated  styrene-butadiene copolymers, sulfonated poly chloro-trif› luoroethylene (PCTFE), sulfonated perfluoroethylene-pro› pylene copolymer (FEP), sulfonated ethylene-chlorotrifluo› roethylene  copolymer  (ECTFE),  sulfonated  polyvinylidenefluoride (PVDF), sulfonated copolymers of  polyvinylidenefluoride with hexafluoropropene and tetra› fluoroethylene, sulfonated copolymers of ethylene and tet› rafluoroethylene (ETFE),  sulfonated polybenzimidazole  (PBI), their chemical derivatives, copolymers, blends and  combinations thereof.  [0142]  The ionic liquid is composed of ions only. Ionic  liquids are low melting temperature salts that are in a molten  or liquid state when above a desired temperature. For  instance, a salt is considered as an ionic liquid if its melting  point is below 100°  C.  If the melting temperature is equal to  or lower than room temperature (25°  C.), the salt is referred  to as a room temperature ionic liquid (RTIL). The IL salts are  characterized by weak interactions, due to the combination  of a large cation and a charge-delocalized anion. This results  in a low tendency to crystallize due to flexibility (anion) and  asymmetry (cation).  [0147]  In the invented process, the first or second polymer  gel electrolyte may contain an ion-conducting polymer.  Preferably, the ion-conducting polymer is selected from  poly(ethylene oxide) (PEO), polypropylene oxide (PPO),  poly(acrylonitrile)  (PAN),  poly(methyl  methacrylate)  (PMMA), poly(vinylidene fluoride) (PVdF), poly bis› methoxy ethoxyethoxide-phosphazenex, polyvinyl chloride,  polydimethylsiloxane, poly(vinylidene fluoride )-hexafluo› ropropylene (PVDF-HFP), a sulfonated derivative thereof, a  sulfonated polymer, or a combination thereof.  [0141]  In the case wherein only one of the electrodes (e.g.  cathode) is a wet mixture electrode, the first liquid electro› lyte may contain an initial concentration, M$_{5}$ ,  of a metal salt  dissolved in a liquid solvent prior to depositing the wet  cathode active material mixture and step (A) includes a  procedure of removing a portion of the liquid solvent after  deposition to increase a metal salt concentration to a final  concentration, M$_{6}$, wherein M$_{6}$>Ms- [0140]  In certain embodiments, the second liquid electro› lyte contains an initial concentration, M$_{3}$ ,  of a metal salt  dissolved in a liquid solvent prior to depositing the wet  anode active material mixture and step (B) includes a  procedure of removing a portion of the liquid solvent after  the depositing step to increase the metal salt concentration to  a final concentration, M$_{4}$ ,  wherein M$_{4}$ >M$_{3}$ .  [0146]  RTILs can possess archetypical properties such as  high intrinsic ionic conductivity, high thermal stability, low  volatility, low (practically zero) vapor pressure, non-flam› mability, the ability to remain liquid at a wide range of  temperatures above and below room temperature, high  polarity, high viscosity, and wide electrochemical windows.  These properties, except for the high viscosity, are desirable  attributes when it comes to using an RTIL as an electrolyte  ingredient (a salt and/or a solvent) in a supercapacitor.  dialkyl-pyrrolidinium, dialkylpiperidinium, tetraalkylphos› phonium, and trialkylsulfonium. Common anions of RTILs  include, but not limited to, BF$_{4}$ -, B(CN) 4 -, CH $_{3}$BF$_{3}$ -,  CH2CHBF$_{3}$-,  CF$_{3}$BF$_{3}$-,  C$_{2}$F$_{5}$ BF$_{3}$-,  n-C$_{3}$F$_{7}$BF$_{3}$-,  n-C$_{4}$ F$_{9}$BF$_{3}$-, PF 6 -, CF $_{3}$CO$_{2}$ -, CF $_{3}$SO$_{3}$ -, N(SO $_{2}$CF$_{3}$ ) 2 -,  N(COCF$_{3}$)(SO$_{2}$CF$_{3}$ t,  N(SO$_{2}$F)$_{2}$-,  N(CN)$_{2}$-,  C(CN)$_{3}$-,  SCN-, SeCN-, CuCl$_{2 }$ -,  AlC1$_{4}$ -,  F(HF)$_{23 }$ -,  etc. Relatively  speaking, the combination of imidazolium- or sulfonium› based cations and complex halide anions such as A1Cl$_{4}$ -,  BF$_{4}$-, CF$_{3}$CO$_{2}$-, CF$_{3}$SO$_{3}$-, NTf 2 -, N(SO $_{2}$F)$_{2}$ -, orF(HF) 23 - results in RTILs with good working conductivities.  [0139]  Thus, in certain embodiments, the first liquid elec› trolyte contains an initial concentration, M$_{1}$ ,  of a metal salt  dissolved in a liquid solvent prior to the sub-step of depos› iting a wet cathode active material mixture and step (A)  includes a procedure of removing a portion of the liquid  solvent after deposition of the wet mixture to increase the  metal salt concentration to a final concentration, M$_{2}$ ,  wherein M$_{2}$>M$_{1}$ .  amount of the liquid solvent is removed to increase the salt  concentration above 2.5 M. The liquid solvent can be a  mixture of two or more liquid solvents; one of the liquid  solvents is more volatile than the other(s ), enabling removal  of some of the solvent. 