University Researchers Develop a Green Supercapacitor

October 01, 2020 by Stephanie Leonida

Texas A&M University researchers use plant-based material lignin to create a stable and efficient supercapacitor.

Researchers from Texas A&M University create a new and potentially more sustainable breed of energy storage device from the use of available biomaterials. The researchers used an organic component found within plant tissue known as lignin and combined this with manganese dioxide in the final design of the device due to their complementary properties.


The Green Supercapacitor

The new green device is lightweight, flexible and more cost-effective compared to other storage devices on the market. The device functions much like a supercapacitor and has the potential to be used to charge devices like electric cars in minutes pending further development and refinement. 


Prototype of Texas A&M’s green supercapacitor. Image used courtesy of Texas A&M University 
Prototype of Texas A&M’s green supercapacitor. Image used courtesy of Texas A&M University 


Supercapacitors are typically composed of two metal foils which are coated with an electrode material such as carbon. While other energy storage devices like batteries have a higher energy density, supercapacitors are more efficient at generating a large amount of electric current in a shorter period of time. This energy burst is what charges devices more quickly than batteries, which take a longer period of time. 

Professor Hong Liang of the J. Mike Walker ’66 Department of Mechanical Engineering and his colleagues at Texas A&M came upon the idea of a green supercapacitor through exploring literature on lignin and metal oxides. Previous studies have found that using these two materials enhances the electrochemical properties of electrodes. 

To create the supercapacitor the Texas A&M research team first purified lignin with a disinfectant (potassium permanganate). An oxidation reaction was then initiated by applying high heat and pressure. This resulted in the breakdown of the disinfectant and the deposition of manganese dioxide on lignin. An aluminium plate was then coated with the lignin and manganese dioxide mixture to create the green electrode. Lastly, an electrolyte was sandwiched between the green electrode and another electrode constituted of aluminum and activated charcoal.

The research team looks forward to a future where green supercapacitors could charge cars in minutes. Image courtesy of Dr. Hong Liang. 

“In this study, we have been able to make a plant-based supercapacitor with excellent electrochemical performance using a low-cost, sustainable method,” said Liang in a recent news release. “In the near future, we’d like to make our supercapacitors 100% environmentally friendly by incorporating only green, sustainable ingredients”, Liang added. 

The green supercapacitor displayed very stable electrochemical properties when tested. The ability of the device to store an electrical charge was observed to change very little even after multitudinous cycles of discharging and charging. Furthermore, the researcher found that the specific capacitance was 900 times higher than what has been reported for other supercapacitors.