Goal
Convert bulk waste carbon materials into high-quality graphene flakes quickly and cheaply, enabling low-cost graphene for composites and reducing the environmental impact of construction materials.
Problem
High cost and limited scalability of graphene production; large amounts of carbon waste (food, plastic, coal, rubber) that contribute to greenhouse-gas emissions; high carbon footprint of cement and concrete.
Concept Summary
A flash Joule-heating process rapidly heats carbon-containing feedstock to ~3000 K in ~10 ms inside a custom reactor, causing instantaneous graphitization into turbostratic graphene. The process is solvent-free, emits non-carbon elements as gases, and requires only the electrical energy supplied to the carbon material.
Detailed Description
The method uses a high-current pulse to heat solid carbon sources (e.g., coal, petroleum coke, biochar, plastic waste, rubber tires, food waste, banana peel, coffee grounds) to ~3000 K within milliseconds. The carbon lattice reorganizes into few-layer graphene with turbostratic stacking, which is easily exfoliated. No furnace, solvents, or reactive gases are needed; excess energy is emitted as a bright flash of light. Yields of 80-90 % graphene purity >99 % have been reported for high-carbon feedstocks. The electricity cost is ~7.2 kJ g^-^1 (~=$100 per ton of graphene). The produced graphene can be mixed into concrete, plastics, metals, plywood, and other composites, where even 0.1 % loading can reduce concrete-related CO_2 emissions by ~33 %.
Principles
- Flash Joule heating
- Rapid thermal shock
- High-temperature graphitization
- Turbostratic stacking for easy exfoliation
- Bottom-up synthesis from heterogeneous carbon feedstock
Scientific Domains
Materials
- Carbon
- Coal
- Petroleum coke
- Biochar
- Carbon black
- Plastic waste
- Rubber tires
- Food waste
- Banana peel
- Coffee grounds
Mechanisms of Action
- Electrical Joule heating of carbon material
- Instantaneous temperature spike (~3000 K)
- Carbon lattice rearrangement to graphene
- Release of non-carbon elements as gases
- Formation of low-defect turbostratic graphene layers
Energy Sources
Applications
- Concrete reinforcement
- Building materials
- Plastic and metal composites
- Plywood and wood products
- Asphalt
- Electronic devices (via graphene films)
Claimed Performance
Yields 80-90 % graphene with >99 % purity; energy cost ~=7.2 kJ g^-^1 (~$100 per ton); production rate targeted at 1 kg day^-^1 within two years; 0.1 % graphene in cement can cut concrete CO_2 emissions by ~33 %.
Experimental Evidence
Nature paper (2020) reports gram-scale flash graphene synthesis in <1 s, Raman spectroscopy showing low D-band intensity, and yields of 80-90 % for high-carbon sources. Lab demonstrations include conversion of coffee grounds and banana peel into single-layer graphene.
Replication Status
Demonstrated at laboratory scale (gram-scale); no independent commercial replication reported.
Limitations
- Requirement of high-current electrical pulse and specialized reactor
- Management of emitted non-carbon gases
- Scaling from gram-scale to industrial throughput
- Dependence on carbon content of feedstock for yield
