Braja K. Mandal
- Professor of Chemistry
B.Sc., University of Calcutta
M.Sc., Indian Institute of Technology
M.Tech., Indian Institute of Technology
Ph.D., Indian Institute of Technology
If you look at future energy storage systems, the potential of Li-S batteries and supercapacitors is tremendous. A successful Li-S technology can offer at least three times more energy density than the existing Li-ion technology, while the supercapacitors are known for their high power density and very long cycle life. Recently, our research group’s focus has been on these energy storage systems. In particular, we have explored a variety of encapsulation technologies in Li-S chemistry to retain polysulfide intermediates in the cathode structure. This strategy is regarded as one of the best ways to suppress polysulfide shuttle, which is responsible for fast capacity decay. The following schemes are a few examples of our synthetic work:
Figure 1. MnO2-Coated Sulfur-Filled Hollow Carbon Nanosphere-Based Cathode Materials for Enhancing Electrochemical Performance of Li-S Cells
Figure 2. A new graphitic carbon nitride-coated dual Core–Shell sulfur cathode for highly stable lithium–sulfur cells
Figure 3. MnO2-Coated Dual Core–Shell Spindle-Like Nanorods for Improved Capacity Retention of Lithium–Sulfur Batteries
Figure 4. Enhancement in Electrochemical Performance of Lithium-Sulfur Cells through Sulfur Encapsulation in Hollow Carbon Nanospheres Coated with Ultra-Thin Aluminum Fluoride Layer
It is noteworthy that our research group has introduced, for the first time, the AlF3 encapsulation protocol in Li-S chemistry, which resulted in very good long-term stability (capacity retention). In the coming months, we wish to introduce two more new encapsulating materials, Ni0.85Se and MoSe2, because of their superior electrical conductivity and potentially strong binding properties with the polysulfide intermediates. The synthetic process for these transition metal chalcogenide materials is underway and we hope to establish conditions for depositing a 5-10 nm coating over a specifically designed S@C cathode material. In addition to this strategy, we wish to focus on improving cathode redox kinetics by doping the mesoporous carbon host with isolated (single atom)/clustered metal atoms, viz., Fe, Ni and Mo. We believe that such a strategy will remarkably lower the energy barriers and speed up the conversion redox reaction kinetics during the charge/discharge process, leading to superior cell performance.
Supercapacitors have several advantages for energy storage when compared to batteries, such as high power density, excellent cycling stability, very fast charge-discharge capability, and safe operation. However, the energy density of supercapacitors is much lower than that of batteries, preventing their widespread use in many potential applications where batteries are less suitable. One such example is regenerative braking, which requires fast and reversible charge storage, as well as long-term cyclability. There are two major energy storage mechanisms in supercapacitors: electrical double-layer capacitive (EDLC) storage and pseudocapacitive storage. Our research group realizes that the development of hybrid supercapacitors (utilizing the advantages of both mechanisms) is essential to achieve high energy density. We are specifically concentrated on the synthesis of very high surface area (>2,500 m2/g) carbon host having polymodal pore size distributions (more in the microporous range) with elemental doping (viz., B and N for achieving high operating voltage) and nanoscale coating of pseudocapacitive materials (such as MoS2 and NiO for achieving high capacitance). If successful, this technology has potential to charge your cellphones in a few seconds as opposed to a few hours for current Li-ion battery-powered cellphones! In a recent work, we have achieved high specific discharge capacitance of 130.5 F/g and energy density 47.9 Wh/kg for the initial cycling. We can do more as we have now an electrolyte in hand that can operate at 3.75 V! If you are coming to Illinois Tech and interested in developing these technologies, you are welcome to participate in these projects. We expect that you appreciate the necessity of doing good literature research, strongly participate in designing a great research plan, and work hard until a significant improvement has been made.
1. Synthesis of a Very High Specific Surface Area Active Carbon and its Electrical Double-Layer Capacitor Properties in Organic Electrolytes, Z. Yue, H. Dunya, M. Ashuri, K. Kucuk, S. Aryal, S. Antonov, B. Alabbad, C. U. Segre, B. K. Mandal, ChemEngineering, 4, 43 (2020).
2. A new graphitic carbon nitride-coated dual Core–Shell sulfur cathode for highly stable lithium–sulfur cells, H. Dunya, Z. Yue, M. Ashuri, X. Mei, Y. Lin, K. Kucuk, S. Aryal, C. U. Segre, B. K. Mandal, Materials Chemistry and Physics, 246, 122842 (2020).
3. MnO2-Coated Dual Core–Shell Spindle-Like Nanorods for Improved Capacity Retention of Lithium–Sulfur Batteries, H. Dunya, M. Ashuri, D. Alramahi, Z. Yue, K. Kucuk, C. U. Segre and B. K. Mandal ChemEngineering, 4, 42; (2020).
4. Solid polymer electrolytes derived from crosslinked polystyrene nanoparticles covalently functionalized with a low lattice energy lithium salt moiety, X. Mei, W. Zhao, Q. Ma, Z. Yue, H. Dunya, Q. He, A. Chakrabarti, C. McGarry, B. K. Mandal, ChemEngineering, 4, 44 (2020).
5. Synthesis and physical properties of new low-viscosity sulfonium ionic liquids, Z. Yue, H. Dunya, X. Mei, C. McGarry, B, K. Mandal, Ionics, 25, 5979–5989 (2019).
6. MnO2-Coated Sulfur-Filled Hollow Carbon Nanosphere-Based Cathode Materials for Enhancing Electrochemical Performance of Li-S Cells, Z. Yue, H. Dunya, K. Kucuk, S. Aryal, Q. Ma, S. Antonov, M. Ashuri, B. Alabbad, Y. Lin, C. U. Segre, and B. K. Mandal, Journal of The Electrochemical Society, 166 (8) A1355-A1362 (2019).
7. Enhancement in Electrochemical Performance of Lithium-Sulfur Cells through Sulfur Encapsulation in Hollow Carbon Nanospheres Coated with Ultra-Thin Aluminum Fluoride Layer, M. Ashuri, H. Dunya, Z. Yue, D. Alramahi, X. Mei, K. Kucuk, S. Aryal, C. U. Segre, and B. K. Mandal, ChemistrySelect, 4, 12622–12629 (2019).
8. Specifically Designed Ionic Liquids—Formulations, Physicochemical Properties, and Electrochemical Double Layer Storage Behavior, Z. Yue, Q. Ma, X. Mei, A. Schulz, H. Dunya, D. Alramahi, C. McGarry, J. Tufts, A. Chakrabarti, R. Saha, B. K. Mandal, ChemEngineering, 3, 58 (2019).
9. Synthesis and physical properties of new fluoroether sulfones, Z. Yue, X. Mei, H. Dunya, Q. Ma, C. McGarry, B. K. Mandal, Journal of Fluorine Chemistry 216, 118–123 (2018).
10. Synthesis and electrochemical properties of partially fluorinated ether solvents for lithium sulfur battery electrolytes, Z. Yue, H. Dunya, S. Aryal, C. U. Segre, B. Mandal, Journal of Power Sources 401, 271–277, (2018).
11. Synthesis and electrochemical properties of new dicationic ionic liquids, X. Mei, Z. Yue, Q. Ma, H. Dunya, B. K. Mandal, Journal of Molecular Liquids 272, 1001–1018 (2018).
12. New oligoether plasticizers for poly(ethylene oxide)-based solid polymer electrolytes, Q. Ma, A. Chakrabarti, X. Mei, Z. Yue, H. Dunya, R. Filler, B. K. Mandal, Ionics, 25(4), 1633-1643 (2018).
13. Synthesis of new fluorine-containing room temperature ionic liquids and their physical and electrochemical properties, X. Mei, Z. Yue, J. Tufts, H. Dunya, B. K. Mandal, J. Fluorine Chem. 212, 26-37 (2018).
Polymer Synthesis- strategies and tactics by Braja K. Mandal (ISBN: 978-0-9841572-0-4): This book covers how different types of polymers are synthesized and presents the most up-to-date developments in polymer chemistry with special emphasis on strategies and tactics to prepare monomers and polymers and to perform newly developed polymerization reactions. The book is designed to accommodate the needs of both advanced undergraduate and graduate students who have a good background in organic chemistry, as well as a stand-alone handy polymer synthesis reference guide.