Biological and Agricultural Engineering

May 28 – Exit Seminar: Synthesis and Characterization of Carbon Nanostructures for Supercapacitors

Thursday, May 28, 2015
4:00 PM


2045 Bainer Hall

 

SPEAKER: Sanliang Zhang  

 

TITLE: Synthesis and Characterization of Carbon Nanostructures for Supercapacitors

 

BSTRACT: Supercapacitors, also known as electrochemical capacitors or ultracapacitors, have been playing an important role in electrical energy storage field to bridge the performance gap between conventional capacitors and batteries, since their first appearing in the marketplace in the 1960s. Either working as an independent power source or as a complement for batteries, therefore, supercapacitors have been indispensable in a number of applications due to their extraordinary high power density and fit-and-forget benefit. More recently, with the increasing awareness of their performance characteristics, supercapacitors are finding their way to more applicable niche markets. As the major working medium inside supercapacitors, high surface area activated carbon is dominating current commercial supercapacitors. In this work, some other porous carbon nanostructures have been investigated as a substitute or performance enhancer for activated carbon inside supercapacitors. Moreover, we also summarized the inconsistencies for supercapacitors performance evaluation and provided some possible solutions.

Firstly, we will provide a general overview of the basic working principle of supercapacitors and their constituting components (aka electrode, electrolyte, separator, current collector and additives). Secondly, a novel electrode fabrication method, named vacuum filtration deposition, to produce graphene-based supercapacitor electrodes will be presented. This vacuum filtration deposition method greatly improved the mass loading of graphene-based supercapacitor electrodes and therefore increased their energy storage ability. Thirdly, we will discuss the effect of graphene morphology on the electrochemical performance of resulting supercapacitor electrodes. We concluded that crumpled graphene is favorable in supercapacitor applications compared to their planar counterpart. Afterwards, we will demonstrate the performance enhancement of conventional activated carbon based supercapacitor upon graphene addition. 50 % increase in power density was concluded, which might have profound practical impact to the industry. Fifthly, we will summarize some of the inconsistencies we encountered for the evaluation of supercapacitors, which severely hindered effective communication in the field. We clarified those inconsistencies and proposed some approaches to mediate this issue. Lastly, we will recap the major conclusions from our study and list some possible future work.

Location
2045 Bainer Hall University of California Davis

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