https://scholar.dgist.ac.kr/handle/20.500.11750/237 2026-04-04T10:34:05Z 2026-04-04T10:34:05Z Han, Dabin Abuawwad, Lamia Kim, Minji Schneemann, Andreas Shanmugam, Sangaraju https://scholar.dgist.ac.kr/handle/20.500.11750/60000 2026-02-09T15:10:32Z 2026-01-31T15:00:00Z

Title: Cationic Covalent Organic Framework-Based Membranes for High-Performance Zn/Br2 Redox Flow Batteries Author(s): Han, Dabin; Abuawwad, Lamia; Kim, Minji; Schneemann, Andreas; Shanmugam, Sangaraju Abstract: Zn/Br2 redox flow batteries (Zn/Br2 RFBs) have attracted significant attention for large-scale energy storage applications due to their high safety and efficiency. The membrane is a critical component of Zn/Br2 RFBs, directly influencing their efficiency and power density. However, designing suitable membranes is challenging due to an intrinsic trade-off between achieving fast bi-ionic species transport (Zn2+ and Br−). Increasing anion transport pathways improves Br− conductivity but simultaneously accelerates Brn− shuttling and self-discharge, while strong Brn− blocking typically restricts anion mobility and causes ionic imbalance. To address this trade-off, a membrane design strategy is proposed that enhances anion conduction while simultaneously suppressing Brn− migration by incorporating a cationic COF construced from ethidium bromide and triformylphloroglucinol (EB-COF) into a Nafion (NF) matrix. The EB-COF exhibits -CHO and -NH2 functional groups on its surface. The interaction between water molecules and these functional groups forms continuous, abundant water networks within the composite membrane, significantly enhancing its ion conductivity. In addition, the abundant quaternary amine groups (N+) of the EB-COF significantly reduce the polybromide (Brn−) shuttle by absorbing Br2 while forming Brn−. In particular, NF/EB-COF(0.3), in which 0.3 wt.% EB-COF is introduced into the NF polymer matrix, exhibits the most effective characteristics and has excellent performance for Zn/Br2 RFBs. Consequently, the Zn/Br2 RFBs assembled with the NF/EB-COF composite membrane demonstrate outstanding performance, achieving an energy efficiency of 89.1% at a current density of 40 mA cm−2.

2026-01-31T15:00:00Z Zafar, Anum Shanmugam, Sangaraju Zhang, Xinyi https://scholar.dgist.ac.kr/handle/20.500.11750/59979 2026-02-09T15:10:49Z 2025-08-31T15:00:00Z

Title: Single Atom Catalysts for Electrochemical CO2 Reduction Reaction: Synthetic Strategies and Mechanistic Insights Author(s): Zafar, Anum; Shanmugam, Sangaraju; Zhang, Xinyi Abstract: Electrocatalytic CO2 reduction is one of the most promising pathways for addressing environmental and green energy concerns while converting CO2 into added value chemicals and fuels. For this purpose, single-atom catalysts (SACs) have emerged as highly active and selective classes of materials toward electrochemical CO2 reduction (CO2RR) due to their unique electronic properties, exposed active centers, and tunable coordination environment. Herein, a critical assessment of the recent development of SACs for CO2RR is presented. Rational design and synthetic strategies of SACs have been summarized. The interaction of ligands and modulation of both activity and selectivity with extensive analysis on local atomic structure and different SAC types is discussed. The reaction mechanisms of SACs based CO2RR and synergistic effect of SACs with nanoparticles and nanoclusters are also highlighted, emphasizing enhanced catalytic performance due to improved charge transfer, optimized binding of intermediates, and improved accessibility of the active site. Finally, the future perspective of SACs based CO2RR is provided.

2025-08-31T15:00:00Z Choudhary, Rubi Shanmugam, Sangaraju Ramanujam, Kothandaraman https://scholar.dgist.ac.kr/handle/20.500.11750/59976 2026-02-09T15:10:48Z 2025-10-31T15:00:00Z

Title: Bottlenecks and Techno-Economic Feasibility of the Zinc-Iodine Flow Battery Author(s): Choudhary, Rubi; Shanmugam, Sangaraju; Ramanujam, Kothandaraman Abstract: Zinc-iodine flow batteries (ZIFB) have emerged as one of the most promising technologies for next-generation grid-scale energy storage systems due to their advantages, which include high energy density, low cost, and environmental friendliness. However, the practical applicability of ZIFB is mainly hindered by low electrolyte utilization, the zinc dendrite problem, iodine precipitation, and membrane instability. Since the negative electrode involves plating of zinc, it is essential to achieve high areal capacity, volumetric capacity, and effective electrolyte utilization, all together. Most literature reports either high volumetric or geometric capacity, but not combined. Those who report high capacities fail to report the same in long-term cycling. Some work explores asymmetric electrolytes whose performance is affected by the crossover of the electrolytes. Although many reviews on the static version of the zinc-iodine battery exist, reviews of ZIFB are scant. This review primarily focuses on the present status and challenges of ZIFB. It offers a comparative analysis of ZIFB with other redox flow batteries and the key factors related to zinc dendrite issues, water shifting, iodine precipitation, and the interaction of iodine species with commonly used polymer membranes. Additionally, the review explores the strategies employed to overcome these challenges, including the use of electrolyte additives (both organic and inorganic), electrode modifications, and cost-effective alternatives to the Nafion membrane. The review concludes by outlining the remaining challenges of ZIFB and the future pathway to address these issues.

2025-10-31T15:00:00Z Mohanraj, Madeshwaran Aparnasree, Moothedath Rajni, K. S. Shanmugam, Sangaraju Ulaganathan, Mani https://scholar.dgist.ac.kr/handle/20.500.11750/59970 2026-02-09T08:40:16Z 2025-12-31T15:00:00Z

Title: Fluorine-doped β-Ni(OH)2-Ti3C2 MXene composite: a bifunctional electrode Author(s): Mohanraj, Madeshwaran; Aparnasree, Moothedath; Rajni, K. S.; Shanmugam, Sangaraju; Ulaganathan, Mani Abstract: Developing a multifunctional material with high capacity, vigorous electrocatalytic activity for both the OER and HER, and long-term stability is a significant challenge for electrochemical applications. In this work, a fluorine-doped beta-nickel hydroxide composite with varying Ti3C2 concentrations has been synthesized. The F-doped Ni(OH)2-Ti3C2_3% (NT-3@NF) electrode exhibits superior electrocatalytic performance compared to other composite electrodes, with overpotentials of 53 mV for the HER and 263 mV for the OER at a current density of 10 mA cm-2 in a 1 M KOH alkaline electrolyte medium. The fluorine-doped beta-Ni(OH)2 composite with Ti3C2 Mxene (beta-Ni(OH)2-Ti3C2_3%), referred to as the NT-3 electrode, achieves a practical specific capacity of 242.16 mAh g-1 at a current density of 1 A g-1, which is 83% of the electrode's theoretical specific capacity. A hybrid capacitor with a gel electrolyte, fabricated for both bare and composite electrodes, was configured as AC & Vert;PVA-KOH & Vert;NT-0 and AC & Vert;PVA-KOH & Vert;NT-3, delivering specific energies of 37.21 and 62.13 Wh kg-1, respectively. The long-term cycle stability of the fabricated supercapacitors has been evaluated over approximately 20 000 cycles at a current density of 1 A g-1. The AC & Vert;PVA-KOH & Vert;NT-3 supercapacitor exhibits 71.2% capacitance retention and a coulombic efficiency of 99.62%. A class of 11 V hybrid capacitor prototypes was also fabricated, and their practical viability has been analyzed to ensure high energy density. Thus, the synthesized multifunctional beta-Ni(OH)2 and F-doped beta-Ni(OH)2-Ti3C2 composite electrode can be a promising candidate for a highly efficient electrode for energy conversion and storage applications.

2025-12-31T15:00:00Z