Research at SDSU has developed a preparation methods for producing functional carbon composites from biochar, an abundant byproduct from biofuel production. The carbon composites have shown to possess smart nano-gate properties to achieve electro-field stimuli-responsive control of ions and electrons transfer, which prevents leakage after charging as well as enables a smart control for charging and discharging of supercapacitors or superbatteries.
To produce functional carbon composite with smart nano-gate, stimuli-responsive polymers or inorganic materials such as silicon or silica will form a coating film on the surface of carbon particles as well as in porous surface of carbonaceous materials. To immobilize polymers and inorganic materials, surface of carbonaceous materials will be modified with oxidization, reduction or other modification to form functional groups containing oxygen, nitrogen, metal ions or other doped elements. Polymers to form stimuli-responsive nano-gate can be immobilized on carbon surface with covalent bond or weak interaction such as H bond or hydrophobic interaction after mixing and posttreatment. Polymers can also be formed by in-situ polymerization on carbonaceous materials surface. Inorganic materials to form stimuli-responsive nano-gate can be immobilized on carbon surface with covalent bond or weak interaction such as a hydrogen bond or hydrophobic interaction after mixing and post-treatment. Inorganic materials film can also be formed by in-situ deposition on carbonaceous materials surface through chemical vapor deposition or precipitation in liquid phase.
The Smart Nano-Gate Super-Carbon composite for a supercapacitor or battery have the potential to achieve the following:
- High capacitance
- Excellent energy and power density
- Good potential stability and low internal resistance
- Excellent recycle capacity
- Long idle energy storage time without leakage or self-discharge
- Controllable charging and discharging speed by controlling electro-field or manganic field or other stimulus in battery or capacitors