Next-generation electronic devices and hybrid electric vehicles (HEVs) need excellent charge storage devices to function well. Currently, majority of the charge storage devices are made from conventional metal sulfide or metal oxide-based supercapacitor electrodes. However, poor electrical conductivity and low energy density are major challenges in the use of supercapacitors, limiting their commercial applications. In contrast, transition metal selenides offer several enhanced electrochemical properties due to their in-built advantageous physicochemical properties including high chemical stability, a narrow bandgap, and low electronegativity that leads to a faster electron-conducting rate than that of metal sulfides and oxides. “A composite formed by the combination of metal selenides and carbon template is a fascinating approach to tune the properties of electrodes for electrochemical applications. Based on this idea, we have designed and constructed a new hybrid composite electrode comprising cobalt selenide nanorod-copper selenide polyhedron-decorated over graphene oxide (CCS@GO), using a wet-chemical strategy”, explains Professor Hyun-Seok Kim from the Division of Electronics and Electrical Engineering, Dongguk University, Seoul, South Korea, who has been actively researching 2D materials and nano- and micro-electronics for energy and sensor devices.

In a recent article made available online on August 9, 2021, and published in volume 427 of Chemical Engineering Journal, Prof. Kim and his research team demonstrated that the resultant composite electrode provides abundant space for migration of ions, and allows swift faradaic redox reactions leading to high storage performance in an electrochemical cell. The team attributed the enhanced electrochemical features to the unique morphology and high surface area of the novel electrode material. They established that the synthesized electrode has outstanding electrochemical charge storage and retention properties. Using the electrodes, they constructed an asymmetric supercapacitor device with a capacitance of 192.8 Fg^-1 @ 1A g^-1; energy density of 54.6 Wh kg^-1; power density 700 W kg^-1, and capacitance retention of about 82.5% over 10,000 cycles. “We achieved our ultimate goal of constructing an electrochemical supercapacitor with improved electrochemical activity and long-term durability,” notes an excited Prof. Kim.

Moreover, the team employed an ecofriendly, cost-effective, energy-efficient, wet-chemical fabrication method with earth-abundant copper and cobalt source materials for developing the new electrodes. Taken together, this development paves the way for user-free, non-flammable energy storage materials for next generation electronic and electrical devices.

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DOI: https://doi.org/10.1016/j.cej.2021.131535

Title of original paper: Unveiling a binary metal selenide composite of CuSe polyhedrons/CoSe₂ nanorods decorated graphene oxide as an active electrode material for

high-performance hybrid supercapacitors

Journal: Chemical Engineering Journal

Dongguk University, founded in 1906, is located in Seoul, South Korea. It comprises 13 colleges that cover a variety of disciplines and has local campuses in Gyeongju, Goyang, and Los Angeles. The university has 1300 professors who conduct independent research and 18000 students undertaking studies in a variety of disciplines. Interaction between disciplines is one of the strengths on which Dongguk prides itself; the university encourages researchers to work across disciplines in Information Technology, Bio Technology, CT, and Buddhism.

Website: http://www.dongguk.edu/mbs/en/index.jsp

Dr. Hyun-Seok Kim (PhD, University of Wisconsin-Madison, USA) is a Professor who teaches at the Division of Electronics and Electrical Engineering at Dongguk University, Seoul, South Korea. His research interests include 2D materials and nano- and micro-electronics for energy and sensor devices. Prior to his current role, he served as a post-doctoral researcher at the University of Wisconsin-Madison and a senior R&D engineer at Intel Corporation, USA. In recent times, along with his colleagues, particularly Dr. K. Karuppasamy and Dr. Dhanasekaran Vikraman, Dr. Kim is actively developing 2D-material-based nanostructures for energy storage and conversion applications.