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New Graphene-based Supercapacitor  Oct 20, 2017

Newly developed graphene-based supercapacitor offers a promising source for greater power and sustained energy

From home appliances to automobiles, cell phones to satellites, modern life is unthinkable without a source of energy. With non-renewable sources of energy, such as oil, gas, and coal, fast getting depleted, race is on to develop clean sustainable sources of energy and the technologies to harness the same.

Research in the area of materials science over the last 10-15 years has presented a set of alternate sources of energy, ranging from conducting polymers to layered materials. Efforts are on by scientists and technologists to synthesize materials that can be developed to be used in electronics or automobiles.   

Led by Dr. Nirmalya Ballav, researchers at IISER Pune and CSIR-NCL have developed a solid state graphene-based supercapacitor that can be used for effective storage and delivery of energy.

As the first step, the team established a cost-effective method for chemical reduction of graphene oxide. Due to fast reduction kinetics of strong reducing agents, the resulting materials display an imbalance in the required characteristics of porosity, surface area, etc. To avoid this difficulty, the team chose to employ a mild reducing agent, FeCl2/HCl that offers slow reduction kinetics. The result was a self-assembled reduced graphene oxide (rGO) with optimal physicochemical characteristics.

rGO (reduced graphene oxide) scored high on both parameters used to assess the potential of the material to serve as an energy storage device: how much energy can it store in a given area (capacity) and how fast (power) can it supply energy when required.

Plawan Kumar Jha (right), PhD student working in the group of Dr. Nirmalya Ballav, demonstrating the application of graphene-supercapacitor to Dr. R. Sharma and Mr. S. Sharma (left) from SPEL Pune 

rGO was also found to have a high charge-discharge cycling stability, which means that it can last longer without getting degraded in the process of delivering energy. While other carbon-based supercapacitors being tested elsewhere last a few thousands of cycles, this newly synthesized material is found to be stable for over 100,000 cycles. Further, the flexible nature of this material allows it to be either drawn into thin sheets or molded into solid bars or pellets.

Owing to several of these desirable features, rGO is now going to be tested by SPEL Technologies for its potential to be used in the automobile industry.

The paper titled “High level supercapacitive performance of chemically reduced graphene oxide” has been accepted for publication in the journal Chem and is available online here.  Authors on this work are Plawan Kumar Jha, Santosh Kumar Singh, Vikash Kumar, Shammi Rana, Sreekumar Kurungot, and Nirmalya Ballav.

- Reported by Shanti Kalipatnapu