Ultrathin Hierarchical Porous Carbon Nanosheets for High-Performance Supercapacitors and Redox Electrolyte Energy Storage

Significance 

Presently, carbon based materials are the most efficiently implemented supercapacitor electrodes. This can be highly attributed to their low cost, excellent electrical conductivity and high surface area. Currently, the design of advanced high-energy-density supercapacitors calls for application of materials that combine hierarchical nanoporous structures with high surface area to facilitate ion transport and excellent electrolyte permeability. Unfortunately, designing of superior carbon materials for high-performance supercapacitors with tailored properties such as chemical stability, electrical conductivity, and large specific and functional surface area is a great challenge. To escape this, inorganic–organic hybrid porous metal–organic frameworks have recently been employed as sacrificial templates/precursors for synthesizing various hierarchical carbon materials, despite the challenges encountered during the controlled transformation of these metal–organic frameworks into 2D porous carbon nanosheets.

Researchers led by Professor Roland Fischer at Technical University of Munich in Germany in collaboration with scientists at Palacky University Olomouc in Czech Republic, developed a scalable strategy for the fabrication of shape-controlled 2D nanoporous carbon sheets by controlled carbonization of a specifically selected potassium-based metal–organic frameworks without any additional chemical etching agent. Furthermore, with scientists from Catalan Institute of Nanoscience and Nanotechnology (ICN2) in Spain and University of Adelaide (UoA) in Australia, they hoped to investigate and elucidate further the properties of the fabricated nanoporous carbon sheets in high energy density superconductors. Their work is currently published in the research journal, Advanced Materials.

The researchers synthesized the 2D carbon sheets from a potassium based-metal organic framework. The team then employed powder X-ray diffraction analysis to confirm the phase purity of the resulting K-MOF.  They then used the fabricated K-MOF as the self-sacrificing template to selectively synthesize the 2D nanoporous carbon sheets via a facile, cost effective, shape controlled approach. Subsequent to the carbonization steps, potassium-based impurities were removed and eventually, the obtained material was dried at 1000 C.

The authors observed that the fabricated nanoporous carbon sheets electrode had the capability to provide an ultrahigh Brunauer–Emmett–Teller surface-area-normalized capacitance. Additionally, the team developed a new strategy of use of “Hybrid Electrolyte” in supercapacitors where the redox-active species (in particular potassium iodide) are introduced in a conventional sulphuric acid electrolyte. This approach led to exceptional further enhancement in the energy density of the symmetric cell thereby maintaining their high power density, which was superior to that of commercial aqueous rechargeable batteries.

The collaborative research study has successfully implemented high-surface-area hierarchical carbon nanosheets with controlled porosity derived from a suitably chosen metal–organic frameworks as self-sacrificial precursor and template for high voltage (1.6V) and high energy density supercapacitors. The ultrahigh value of the Brunauer–Emmett–Teller surface-area-normalized capacitance obtained has been seen to be remarkably superior to that of any other metal–organic frameworks -derived carbon material. The work therefore provided a new guideline for further development of carbon-based energy-storage systems with battery-level energy and capacitor-level power density.

K-MOF – {K3[C6H3(CO2)(CO2H0.5) (CO2H)]2}(H2O)2

Ultrathin Hierarchical Porous Carbon Nanosheets for High-Performance Supercapacitors and Redox Electrolyte Energy Storage- Advances in Engineering

About the author

Dr. Jayaramulu Kolleboyina, currently a Senior Researcher at the Regional Centre of Advanced Technologies and Materials (RCPTM), Palacký University in Olomouc, Czech Republic with Prof. Dr. Radek Zbořil. He received PhD in Material Science from Jawaharlal Nehru Centre for Scientific Research (JNCASR) Bangalore in 2014. After his PhD studies, he had an opportunity to work with Prof. Dr. CNR Rao, ICMS Bangalore and ICN2, Barcelona, Spain with Prof. Daniel Maspoch as a Research associate.

He has been postdoctoral fellow with Prof Roland A Fischer using prestigious Alexander von Humboldt (AvH) Fellowship at Ruhr-University Bochum (RUB) and Technical University Munich (TUM), Germany (2015-2017). His Current research interest includes the synthesis of various novel hybrid porous materials and two-dimensional metal-organic frameworks for energy and environmental mainly, water/gas purification applications.

About the author

Dr. Deepak Dubal is currently working as Vice Chancellor’s Research Fellow at University of Adelaide, Australia. He received his PhD in 2011 from Shivaji University Kolhapur, India and joined as a Post-doctoral Fellow at Gwangju Institute of Science and Technology (GIST), South Korea. In 2012, he was awarded “Alexander von Humboldt” fellowship to work at Chemnitz University of Technology, Germany. He is also a recipient of “Marie-Curie” fellowship in 2014 to join Catalan Institute of Nanoscience and Nanotechnology ICN2 (CSIC-BIST), Spain.

His research expertise is in design and development of multifunctional hybrid materials for clean energy conversion and storage technologies with special focus on supercapacitors, lithium-ion batteries, Li-ion capacitors and electrochemical flow cells. He is member of Editorial board Scientific Reports (Nature Publishing Group) and recently nominated in top four young scientists for USERN Prize-2017.

About the author

Radek Zbořil (*1973) received his Ph.D. degree at the Palacky University in Olomouc, Czech Republic. After his doctoral studies, he spent some time at universities around the world in locations such as Tokyo, Delaware, and Johannesburg. Currently, he is a professor at the Department of Physical Chemistry and a General Director of the Regional Centre of Advanced Technologies and Materials at the Palacky University in Olomouc, Czech Republic.

His research interests focus on nanomaterial research including iron- and iron oxide-based nanoparticles, silver nanoparticles, carbon nanostructures, and magnetic nanoparticles, their synthesis, physicochemical characterization, and applications in catalysis, water treatment, antimicrobial technologies, medicine, energy storage and biotechnologies. He is a member of the editorial board of several journals (e.g. Applied Materials Today, Scientific Reports). He is co-author of several US and European patents and more than 450 publications, which have received over 16 000 citations. His H-index is 58 (Scopus, April 2018).

About the author

Prof. Pedro Gomez-Romero, FRSC (B. Sc. and Ms Sc. Universidad de Valencia, Spain. Ph.D. in Chemistry, Georgetown University, USA, 1987, with Distinction) is Full Professor of the Spanish National Research Council (CSIC) since 2006. He is the Head of the NEO-Energy Group at the Catalan Institute of Nanoscience and Nanotechnology, ICN2 (CSIC-BIST) since 2007. Sabbatical Fellow at the National Renewable Energy Laboratory, USA (1998-99). Director of projects on energy materials, hybrid organic-inorganic nanostructures, graphene, nanocomposite materials for energy storage and conversion (lithium batteries, supercapacitors, flow batteries, solar-thermal energy, nanofluids). Cofounder of Earthdas graphene mobility spin-off Company.

Author of more than 200 publications. Scientific editor of the books “Functional Hybrid Materials” P. Gómez-Romero, C. Sanchez (Eds.) (Wiley-VCH 2004) and “Metal Oxides in Supercapacitors” (Elsevier, 2017, D P Dubal , P. Gomez-Romero) and author of four award-winning popular science books. CIDETEC Award for Research on Electrochemistry 2017.

About the author

Prof. Dr. Roland A Fischer

Prof. Roland A. Fischer received his Dr. rer. nat. (1989) and Habilitation (1995) from Technical University Munich (TUM). He was Associate Professor at Heidelberg University (1996-1997) and Full Professor for Inorganic Chemistry at Ruhr-University Bochum (1997-2015). In 2016 he returned to TUM and took the Chair of Inorganic and Metal-Organic Chemistry. He has been elected Vice President of the Deutsche Forschungsgemeinschaft (DFG) in 2016.

His research focuses on main group 13/transition metal compounds and clusters, precursors for metal-organic chemical vapor deposition (MOCVD) and the materials chemistry of metal-organic frameworks (MOFs).

Reference

Kolleboyina Jayaramulu, Deepak P. Dubal, Bhawna Nagar, Vaclav Ranc, Ondrej Tomanec, Martin Petr, Kasibhatta Kumara Ramanatha Datta, Radek Zboril, Pedro Gómez-Romero, Roland A. Fischer. Ultrathin Hierarchical Porous Carbon Nanosheets for High-Performance Supercapacitors and Redox Electrolyte Energy Storage. Adv. Mater. 2018, 1705789

 

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