Feb.28,2019  20  US 2019/0067732 Al  Example 19: Graphene-Enhanced Tin Oxide  Particulates as an Anode Active Material  Example 17: Graphene-Enhanced Nano Silicon  Fabricated from TEOS as an Anode Active  Material of a Lithium-Ion Battery  Example 20: Preparation of Graphene-Supported  MnO$_{2 }$ and NaMnO$_{2 }$ Cathode Active Material for  Sodium-Ion Cells  Example 21: Preparation of Electrodes for  Potassium Metal Cells  Example 22: Preparation and Electrochemical  Testing of Various Electrochemical Cells  Example 18: Cobalt Oxide (Co$_{3}$O$_{4}$ )  Particulates as  an Anode Active Material  [0192]  For most of the anode and cathode active materials  investigated, we prepared electrochemical cells ( e.g. alkali  metal-ion cells or alkali metal cells) using both the presently  invented method and the conventional method.  [0187]  An appropriate amount of inorganic salts Co(NO$_{3}$ )  $_{2}$.6H$_{2}$O and, subsequently, ammonia solution (NH$_{3}$ .H$_{2}$O, 25  wt %) were slowly added into a GO suspension. The  resulting precursor suspension was stirred for several hours  under an argon flow to ensure a complete reaction. The  obtained Co(OH)igraphene precursor suspension was  divided into two portions. One portion was filtered and dried  under vacuum at 70° C. to obtain a Co(OH)$_{2}$/graphene  composite precursor. This precursor was calcined at 450°  C.  in air for 2 h to form the layered Co$_{3}$Oigraphene compos› ites, which are characterized by having Co$_{3}$O$_{4}$-coated  graphene sheets overlapping one another. These Co$_{3}$O$_{4}$ - coated graphene sheets are another high-capacity anode  active material.  [0186]  Although LiCoO$_{2 }$ is a cathode active material,  Co$_{3}$O$_{4 }$ is an anode active material of a lithium-ion battery  since LiCoO$_{2 }$ is at an electrochemical potential of approxi› mately +4.0 volts relative to Li/Li+ and Co$_{3}$O$_{4 }$ is at an  electrochemical potential of approximately +0.8 volts rela› tive to Li/Li+.  [0191]  A sheet of potassium-coated graphene film was  used as the anode active material while a layer of PVDF› bonded reduced graphene oxide (RGO) sheets, supplied  from Angstron Materials, Inc. (Dayton, Ohio), was used as  the cathode active material. The electrolyte used was 3.0 M  ofKClO$_{4 }$ salt dissolved in a mixture of propylene carbonate  and DOL (1/1 ratio). Charge-discharge curves were obtained  at several current densities (from 50 mA/g to 50 A/g),  corresponding to different C rates, with the resulting energy  density and power density data measured and calculated.  [0190]  Additionally, NaMnO$_{2 }$ and NaMnO$_{2}$/graphene  composite were synthesized by ball-milling mixtures of  Na$_{2}$CO$_{3 }$ and MnO$_{2 }$ (at a molar ratio of 1 :2), with or without  graphene sheets, for 12 h followed by heating at 870°  C. for  10 h.  [0189]  The MnO$_{2 }$ powder was synthesized by two meth› ods (each with or without the presence of graphene sheets).  In one method, a 0.1 mol/L KMnO$_{4 }$ aqueous solution was  prepared by dissolving potassium permanganate in deion› ized water. Meanwhile 13.32 g surfactant of high purity  sodium bis(2-ethylhexyl) sulfosuccinate was added in 300  mL iso-octane ( oil) and stirred well to get an optically  transparent solution. Then, 32.4 mL of 0.1 mol/L KMnO$_{4 }$ solution and selected amounts of GO solution were added in  the solution, which was ultrasonicated for 30 min to prepare  a dark brown precipitate. The product was separated,  washed several times with distilled water and ethanol, and  dried at 80°  C. for 12 h. The sample is graphene-supported  MnO$_{2 }$ in a powder form, which was dispersed in a liquid  electrolyte to form a slurry and coated onto a surface of Al  foil.  [0185]  A certain amount of the dried TPM particles was  then put into a muffle furnace and calcined at 400°  C.-600°  C. for 2 hours under air purging to remove the carbon  content from the nanocomposite, producing graphene-free  yellow-color silicon nano powders. Both Si nano powder  and graphene-wrapped Si nano particles were used as a  high-capacity anode active material.  [0184]  Dilute 1 wt.% N002-PS to 0.2 wt.% N002-PS by  DI water, and place the diluted PS solution to the ultrasonic  bath and ultrasonic process for 30 minutes. Gradually add  TEOS (0.2 wt.% N002-PS:TEOS=5:2) while stirring the PS  solution. Then, keep stirring for 24 hours to get a complete  hydrolysis of TEOS. Dropwise add 10% NH$_{3}$ .H$_{2}$O till the  formation of gel, and the gel can be called as TP gel. Grind  the TP gel to tiny particles. Oven dries at 120°  C. for 2 hours,  at 150°  C. for 4 hours. Mix the dried TP particles with Mg  in a ratio of 10:7. Use 20 times amount of7 mm SS balls and  ball mill under Argon protection, gradually increase the  rotating speed to 250 rpm. Put certain amount of TPM  powders in Nickel crucible and heat treatment at 680°  C.  Prepare certain amount of 2M HCl solution. Then gradually  add heat treated TPM powders to the acid solution. Keep the  reaction for 2-24 hours, and then put the turbid liquid to the  ultrasonic bath and ultrasonic process for 1 hour. Pour out  the suspension to the filtration system. Discard the bottom  large particles. Use DI water to rinse three times. Dry the  yellow paste and blend the yellow paste to powders. The  as-prepared nano particle has a SSA value range of30 m $^{2}$/g  to 200 m $^{2}$/g due to different graphene contents.  [0188]  Tin oxide (SnO$_{2}$ )  nano particles, an anode active  material, were obtained by the controlled hydrolysis of  SnC1$_{4}$ .5H$_{2}$O with NaOH using the following procedure:  SnC1$_{4}$ .5H$_{2}$O (0.95 g, 2.7 m-mol) and NaOH (0.212 g, 5.3  m-mol) were dissolved in 50 mL of distilled water each. The  NaOH solution was added drop-wise under vigorous stirring  to the tin chloride solution at a rate of 1 mL/min. This  solution was homogenized by sonication for 5 min. Subse› quently, the resulting hydrosol was reacted with the GO  dispersion for 3 hours. To this mixed solution, few drops of  0.1 M of H$_{2}$ SO$_{4 }$ were added to flocculate the product. The  precipitated solid was collected by centrifugation, washed  with water and ethanol, and dried in vacuum. The dried  product was heat-treated at 400° C. for 2 h under Ar  atmosphere.  a dark brown prec1p1tate. The product was separated,  washed several times with distilled water and ethanol, and  dried at 80°  C. for 12 h. The sample is graphene-supported  MnO$_{2 }$ in a powder form, which was mixed in a liquid  electrolyte to form a wet cathode active material mixture,  which was coated onto a current collector (carbon-protected  Al foil). 