Renewable Energy, Sustainability and the Environment, Energy, Chemistry, Inorganic Chemistry
10
Scopus Publications
Scopus Publications
A 45.6 m NaCTFSI/NaFSI hybrid electrolyte for high-voltage aqueous sodium-ion batteries operable at subzero temperatures Thileep Kumar Kumaresan, Kyunglim Pyo, Joon Seop Kwak, Woon-Bae Park, Hyeon Su No, et al. Science Advances, 2026 Aqueous sodium-ion batteries (SIBs) offer a safe and sustainable energy storage option, but their performance is restricted by the narrow electrochemical stability window (ESW) of water and poor low-temperature operability of conventional water-in-salt electrolytes (WISEs). Here, we show that sodium cyano(trifluoromethanesulfonyl)imide (NaCTFSI) addresses these issues. A 17.6 m NaCTFSI solution forms a true WISE, providing an ESW of 2.78 volts and high-voltage compatibility, but crystallizes below room temperature, severely degrading performance. To overcome this, we systematically explore a eutectic-like hybrid electrolyte by mixing NaCTFSI (14.1 m ) with sodium bis(fluorosulfonyl)imide (NaFSI; 31.5 m ), representing the most concentrated Na + -based WISE to date, which remains liquid down to −20°C and extends the ESW to 3.07 volts. Incorporating CTFSI − anions mitigates FSI − -induced anodic corrosion, ensuring long-term cyclability. Electrochemical tests confirm that KMnC | hybrid | NaMnF full cells sustain over 500 charge-discharge cycles across a wide temperature range, maintaining high capacity even at −20°C, demonstrating a promising platform for safe and wide-climate aqueous SIBs.
Highly Concentrated Asymmetric KTFSI for Aqueous Potassium Ion Batteries Thileep Kumar Kumaresan, Amol Bhairuba Ikhe, Woon‐Bae Park, S. J. Richard Prabakar, Hyeon Su Noh, et al. Advanced Energy Materials, 2024 Potassium imide salt (KCTFSI), featuring cyano (C≡N) and trifluoromethanesulfonyl (TFSI) branches, is reported for the first time as a promising electrolyte for aqueous potassium‐ion batteries (KIBs). In contrast to the limited solubility of symmetric KTFSI (1.5m), asymmetric KCTFSI achieves a high saturation concentration of 32.2m within a “water‐in‐salt” region. Experimental and theoretical studies reveal that the remarkable enhancement of solubility is associated with the asymmetry of CTFSI anions and likely the preferential formation of contact‐ion pairs through C≡N coordination. The 32.2m KCTFSI solution not only extends the electrochemical stability window (3.80 V on Al) but also maintains a liquid state at low temperatures (−15 °C) for an extended period, in sharp contrast to the immediate solidification of potassium bis(fluorosulfonyl)imide (KFSI, 30m) and potassium trifluoromethanesulfonate (KOTF, 22m) solutions. Thanks to its wide voltage window and supercooling behavior, KCTFSI demonstrates excellent compatibility with perylene‐3,4,9,10‐tetracarboxylic diimide (PTCDI) anode and KVPO4F (or K2Fe[Fe(CN)6]·2H2O) cathode over a wide temperature range. For instance, full cells of PTCDI/KCTFSI/KVPO4F exhibit reasonable cyclability with an average discharge voltage of 1.7 V over 300 charge/discharge cycles at −15 °C. it is anticipated that this work will inspire new designs of hybrid electrolytes based on CTFSI to advance the realization of viable aqueous KIBs.
Template assisted synthesis of nanoporous carbon from bio-weed of ipomoea carnea stems for supercapacitor applications T.K. Kumaresan, A.M. Shanmugharaj, K. Raman, S. Raghu Asian Journal of Chemistry, 2019 In this study, we report the hierarchically nanoporous activated carbons syntheses from most abundant bio-weed source of Ipomoea carnea stems by nickel foam template assisted with chemical and thermal activation method. The mixture of ferric chloride and diethyl ether of the activating agent and the impregnation ratios are investigated under constant temperature at 800 °C for 2 h. The effective novel synthesized scheme and hierarchical nanoporous carbon structure with large specific surface areas of 1264.9 m2 g-1 and mean pore diameter of 2.1628 nm. The electrochemical performance of prepared nanoporous structured carbon electrode is studied in non-aqueous (TEABF4) electrolyte, which exhibits high specific capacitance of 257 Fg-1 maximum energy density of 61.46 Wh kg-1 and power density of 13.32 kW kg-1 at 1 Ag-1 with remarkable capacity retention of 90 % for 10000 cycles. Therefore the present results show the suitability of synthesized material for use in energy storage applications. The representing promising application as a green route to synthesis advance nanoporous carbon materials from Ipomoea carnea biomass for high-capacity supercapaciors.
Hierarchically porous structured carbons from abutilon indicum biomass for superior performance of symmetric aqueous supercapacitor Research Journal of Chemistry and Environment, 2019
