Found a most interesting patent from 1997.
It gives the following method to obtain a carbon suspension.
"Water (pH: 7) was used as an electrolyte solution. An negative electrode was made by bending a mesh plate of stainless steel in a cylindrical shape to have a diameter of 100 mm. A positive electrode of a graphite bar having a diameter of 20 mm and a length of 100 mm, was inserted in the cylindrical negative electrode. Direct currents of 3A were supplied for twenty four hours to produce a colloidal carbon suspension."
Robert Murray Smith did something similar but he thought that the suspension was graphene.
The patent then goes on to describe how this carbon suspension was used to restore decidedly dead batteries, giving 16 separate 'how to do it' examples.
Time for some experiments
It gives the following method to obtain a carbon suspension.
"Water (pH: 7) was used as an electrolyte solution. An negative electrode was made by bending a mesh plate of stainless steel in a cylindrical shape to have a diameter of 100 mm. A positive electrode of a graphite bar having a diameter of 20 mm and a length of 100 mm, was inserted in the cylindrical negative electrode. Direct currents of 3A were supplied for twenty four hours to produce a colloidal carbon suspension."
Robert Murray Smith did something similar but he thought that the suspension was graphene.
The patent then goes on to describe how this carbon suspension was used to restore decidedly dead batteries, giving 16 separate 'how to do it' examples.
Time for some experiments
Patent Public Search | USPTO
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