Energy storage device and methods for making and use

Abstract

An electrode in an energy storage device, including: an activated carbon, including: a surface area of from 1000 to 1700 m 2 /g; a pore volume from 0.3 to 0.6 cc/g; a chemically bonded oxygen content of 0.01 to 1.5 wt %; and a pH of from 7.5 to 10. Also disclosed is a method of making the activated carbon, the electrode, and the energy storage device.

1 .- 10 . (canceled) 
     
     
         11 . A method of making an activated carbon, comprising:
 either:   carbonizing a suitable carbon source material to form a char, the carbon source material being selected from the group consisting of wheat flour, walnut flour, corn flour, corn starch, rice flour, potato flour, beets, millet, soybean, barley and cotton, nut shells, a phenolic resin, polyvinyl alcohol), polyacrylonitrile, and combinations thereof;   or:   providing a suitable carbonaceous material selected from the group of char, coke, coal, pitch, activated carbon, or combinations thereof;   powdering the carbonized source material or the provided carbonaceous material to fine particles having a d 50  of about 3 to 10 microns;   heating a mixture of the fine particles and an alkali hydroxide (MOH) at a MOH:char or carbon weight ratio from 2.5:1 to 0.5:1 to produce the activated carbon.   
     
     
         12 . The method of  claim 11 , wherein the MOH:char or MOH:carbon weight ratio is of from 1.5:1 to 1:1. 
     
     
         13 . The method of  claim 12 , wherein the MOH is NaOH, KOH, or a mixture thereof. 
     
     
         14 . The method of  claim 11 , wherein the heating is accomplished in a furnace in a N 2  atmosphere at from 600 to 1000° C., for from 0.25 to 4 hrs. 
     
     
         15 . The method of  claim 11 , further comprising introducing water vapor after the heated mixture is cooled to from 100° C. to 400° C. 
     
     
         16 . The method of  claim 11 , further comprising washing and filtering the activated carbon, sequentially in: DI water, a HCl solution, and DI water, until the filtrate pH is approximately the same pH as the DI water. 
     
     
         17 . The method of  claim 16 , further comprising heat treating the washed and filtered activated carbon in an inert atmosphere, a reducing atmosphere, or a combination thereof, at from 500 to 1000° C., for from 0.25 to 4 hrs.