Rice waste can be used as a sustainable energy source, scientists have proven.
Researchers from the University of Michigan have produced solid carbon by burning rice husk ash. Interestingengineering.com reports.
Properly processed rice husk ash can produce a form of carbon that can outperform graphite in batteries. This “solid carbon” has a unique nanostructure that allows it to store more energy than graphite, which is standard in lithium-ion batteries.
Rice husk ash is mostly composed of silica (about 90%) and carbon (about 10%). The research team has developed a method to extract high-purity silica from rice husk ash. After the silica is partially removed from rice husk ash through a process called depolymerization, the remaining ash is 60% to 70% carbon, the scientists explained.
Initially, the carbon residue from rice husk ash was thought to be amorphous, meaning it had no definite structure. However, advanced spectroscopic analysis revealed the presence of tiny graphite structures embedded in an amorphous carbon matrix. This unique combination, known as solid carbon, exhibits improved properties compared to pure amorphous carbon.
During tests, the solid carbon obtained from rice husk ash demonstrated superior electrochemical performance than commercial solid carbon and graphite. This suggests that it could be used as an anode in lithium-ion batteries.
Solid carbon batteries can store significantly more energy than traditional graphite counterparts. Scientists say that a gram of graphite can store about 370 mAh of electricity. On the other hand, commercial solid carbon can store about 500 mAh per gram.
Notably, solid carbon from rice husk ash outperforms both commercial solid carbon and graphite. It provides a storage capacity exceeding 700 mAh per gram, which is twice that of graphite.
Solid carbon from rice husk ash can meet the growing demand for batteries for electric vehicles and renewable energy sources. This innovative technology offers a more sustainable and cost-effective solution, reducing both environmental impact and production costs.