Preparation and characterization of Pb nanoparticles on mesoporous carbon nanostructure for advanced lead-acid battery applications

Sadhasivam, T.,Dhanabalan, K.,Roh, S. H.,Kim, S. C.,Jeon, D.,Jin, J. E.,Shim, J.,Jung, H. Y. Springer Science + Business Media 2017 Journal of materials science Materials in electron Vol.28 No.7

<P>To enhance the electrochemical energy performance, the lead nanoparticles on mesoporous carbon (Pb on MPC) were prepared and characterized for advanced lead acid battery (Ad-LAB) applications. At present, Ad-LAB garners significant attention in energy storage devices because of its high charge acceptance. However, the major problem has associated with the large crystallization of PbSO4 in negative electrode during unit cell operation. To minimize this issue, Pb nanoparticles have incorporated on MPC in this present investigation. The Pb on MPC has prepared through facile chemical reduction process. The structural analysis of Pb, MPC, and Pb on MPC have confirmed by X-ray diffraction analysis. The specific surface area (SSA) and pore size distribution of MPC and Pb on MPC has obtained through Brunauer-Emmett-Teller measurements. The obtained SSA is 245.38 and 32.42 m(2) g(-1) for MPC and Pb on MPC, respectively. Additionally, the incorporation of Pb on MPC has confirmed by the microstructural analysis of high resolution transmission electron microscopy. The obtained particle sizes of the Pb nanoparticles are similar to 5 nm. Based on the structural, microstructural and cyclic voltammetry analysis, we suggest that Pb on MPC can be used as an efficient active material for negative electrode in Ad-LAB systems.</P>

A novel structured nanosized CaO on nanosilica surface as an alternative solid reducing agent for hydrogen fluoride removal from industrial waste water

Sadhasivam, T.,Lim, Min-Hwa,Jung, Do-Sung,Lim, Hankwon,Ryi, Shin-Kun,Jung, Ho-Young Academic Press 2019 Journal of Environmental Management Vol. No.

<P><B>Abstract</B></P> <P>In the semiconductor industry, perfluorinated compound removal is a major concern owing to the formation of highly toxic and hazardous hydrogen fluoride (HF) as a by-product. Calcium oxide (CaO) can be considered a promising material for HF sorption reaction process. However, the easier reaction between CaO and H<SUB>2</SUB>O results in the formation of Ca(OH)<SUB>2</SUB>, which ultimately limits the usefulness of CaO. The objective of the research work is preparation of CaO nanoparticles on hydrophobic silica (SiO<SUB>2</SUB>) to use as a alternative solid reducing catalyst for efficient HF removal process. High-resolution transmission electron microscopy micrographs confirmed that the as-prepared CaO particles are <5 nm in size and the smaller sized CaO nanoparticles are homogeneously anchored on the entire surface of ∼100 nm spherical SiO<SUB>2</SUB> nanoparticles. The reaction-enhanced regenerative catalytic system (RE-RCS) was used to measure the HF removal efficiency. HF is removed more efficiently using CaO on SiO<SUB>2</SUB> than using CaO alone. At the outlet of the RE-RCS, the obtained HF concentrations are 2811.4 and 2166.1 ppm after a 3 h reaction using CaO and CaO on SiO<SUB>2</SUB> as the sorbent, respectively. The lower concentration of HF at the outlet of the system using CaO on SiO<SUB>2</SUB> indicates that HF sorption is remarkably enhanced using CaO on SiO<SUB>2</SUB> inside the RE-RCS. In addition, the presence of a hydrophobic region in the catalyst sorbent prevents the reaction between CaO and water, which leads to avoiding the formation of Ca(OH)<SUB>2</SUB>. These phenomena significantly enhance the HF removal efficiency and CaF<SUB>2</SUB> formation process.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CaO (<5 nm in size) homogeneously anchored on the entire surface of ∼100 nm SiO<SUB>2</SUB>. </LI> <LI> CaO on hydrophobic SiO<SUB>2</SUB> used as a solid reducing catalyst for HF removal process. </LI> <LI> Hydrophobic region in the catalyst sorbent prevents the formation of Ca(OH)<SUB>2</SUB>. </LI> <LI> The HF removal efficiency is increased by the addition of SiO<SUB>2</SUB> to the CaO sorbent. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>The as-prepared new sorbent material consisting of CaO nanoparticles on hydrophobic SiO<SUB>2</SUB> nanoparticles can be considered an efficient solid reducing agent for highly hazardous HF removal. In addition, the by-product CaF<SUB>2</SUB> can be considered for use in ceramics, building materials, and biomedical components.</P> <P>[DISPLAY OMISSION]</P>

Electro-analytical performance of bifunctional electrocatalyst materials in unitized regenerative fuel cell system

Sadhasivam, T.,Palanisamy, Gowthami,Roh, Sung-Hee,Kurkuri, Mahaveer D.,Kim, Sang Chai,Jung, Ho-Young Elsevier 2018 International journal of hydrogen energy Vol.43 No.39

<P><B>Abstract</B></P> <P>The unitized regenerative fuel cell (URFC) is a round-trip energy conversion device for efficient energy storage systems that offers promising electrochemical energy conversion and environmentally friendly features. The electrocatalyst is a key component for operating URFC unit cell devices. Optimal electrocatalyst materials should be bi-functional with catalytic activity for the oxygen reduction and oxygen evolution reactions (ORR and OER). Over the past few decades, platinum has been recognized as a promising bi-functional electrocatalyst material for the URFC system. However, the ORR and OER activity of Pt is inadequate during the round-trip energy conversion process due to the formation of an oxide layer (PtO<SUB>x</SUB>) and the high onset potential for H<SUB>2</SUB> evolution. To address these issues, extensive effort has been made to enhance the OER performance without affecting the ORR performance. The most efficient alternative electrocatalyst materials comprise combinations of platinum group metals (PGMs) and their oxides, especially PtIr, PtIrRu, PtIrO<SUB>2</SUB>, PtIrIrO<SUB>2</SUB>, and PtIrO<SUB>2</SUB> RuO<SUB>2</SUB>. This comprehensive review emphasizes the potential of various bifunctional electrocatalyst materials for renewable energy generation in the URFC system. Herein, we discuss the limitations of Pt electrocatalysts in the URFC-OER process based on the reaction mechanism. The classification of different bifunctional electrocatalysts is extensively reviewed and highlighted based on the structural, microstructural, fuel cell-ORR, and water electrolysis-OER characteristics, round-trip energy conversion efficiency, inadequacies, and advantages. Taking these features into account, we discuss the possibilities and performance of cost-effective bifunctional electrocatalyst materials for the ORR/OER electro-catalytic process in advanced URFC systems. This review presents an exclusive vision for the development of bifunctional electrocatalyst materials and should stimulate research on bifunctional electrode-based URFC systems.</P> <P><B>Highlights</B></P> <P> <UL> <LI> URFC is an efficient round-trip energy conversion device with high specific energy. </LI> <LI> Bifunctional electrocatalyst is a key component for operating URFC unit cell. </LI> <LI> Pt suffered by formation of PtO<SUB>x</SUB> layer and high onset potential for H<SUB>2</SUB> evolution. </LI> <LI> Pt/IrO<SUB>2</SUB> is superior electrocatalyst material for efficient ORR/OER performances. </LI> <LI> Cost-effective and novel structured electrocatalysts are an alternative to PGM. </LI> </UL> </P>

Low permeable composite membrane based on sulfonated poly(phenylene oxide) (sPPO) and silica for vanadium redox flow battery

Sadhasivam, T.,Kim, Hee-Tak,Park, Won-Shik,Lim, Hankwon,Ryi, Shin-Kun,Roh, Sung-Hee,Jung, Ho-Young Elsevier 2017 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.42 No.30

<P><B>Abstract</B></P> <P>The proton conductivity and vanadium permeability of organic-inorganic (sulfonated poly (phenylene oxide) (sPPO)-nano sized sulfonated silica (sSiO<SUB>2</SUB>)) hybrid membrane were investigated for application in a vanadium redox flow battery (VRFB) system. Significant attention is being paid to PPO polymers as a replacement for Nafion<SUP>®</SUP> membranes due to their relatively low cost and ease of sulfonation. The attachment of a sulfonic acid (SO<SUB>3</SUB>H) functional group to PPO and SiO<SUB>2</SUB> was confirmed using Fourier Transform Infrared Spectroscopy (FTIR). The hybrid membrane (sPPO-2% sSiO<SUB>2</SUB>) exhibited increased thermal stability, water uptake (WU), ion exchange capacity (IEC) and proton conductivity (IC) compared with a conventional organic sPPO membrane. The proton conductivity of the hybrid membrane increased considerably compared to sPPO alone, resulting from the 2% sSiO<SUB>2</SUB> nanoparticles added homogeneously to the polymer matrix. The proton conductivities of the sPPO and hybrid membranes were 0.050 and 0.077 S/cm, respectively. The increased proton conductivity of the hybrid membrane was attributed to the enhanced hydrophilic properties of SO<SUB>3</SUB>H in the membranes. In addition, inorganic particles in the polymer matrix acted as a barrier for vanadium ion crossover. During VRFB unit cell operation, vanadium ion (VO<SUP>2+</SUP>) crossovers were measured as 14.66, 1.955 and 0.173 mmol L<SUP>−1</SUP> through Nafion<SUP>®</SUP>212, sPPO and hybrid membranes, respectively, and VO<SUP>2+</SUP> permeability were 2.22 × 10<SUP>−7</SUP>, 2.50 × 10<SUP>−8</SUP> and 4.76 × 10<SUP>−9</SUP> cm<SUP>2</SUP> min<SUP>−1</SUP> for Nafion<SUP>®</SUP>212, sPPO and hybrid membranes, respectively. Based on our experimental results, low cost organic-inorganic hybrid membranes as prepared provide an efficient alternative membrane material for advanced VRFB systems.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel Organic-Inorganic hybrid structured membrane for advanced VRFB system. </LI> <LI> PPO as a replacement for Nafion<SUP>®</SUP> membranes due to low cost and ease of sulfonation. </LI> <LI> Proton conductivity increased to hybrid membrane (0.077 S/cm) compared to sPPO alone. </LI> <LI> VO<SUP>2+</SUP> permeability of sPPO-sSiO<SUB>2</SUB> membrane is significantly lower than Nafion<SUP>®</SUP>212. </LI> <LI> sSiO<SUB>2</SUB> in the sPPO polymer matrix acted as a barrier for vanadium ion crossover. </LI> </UL> </P>

A comprehensive review on unitized regenerative fuel cells: Crucial challenges and developments

Sadhasivam, T.,Dhanabalan, K.,Roh, Sung-Hee,Kim, Tae-Ho,Park, Kyung-Won,Jung, Seunghun,Kurkuri, Mahaveer D.,Jung, Ho-Young Pergamon Press 2017 International journal of hydrogen energy Vol.42 No.7

<P><B>Abstract</B></P> <P>From extensive reported analyses, we reviewed the limitations, challenges, and advanced developments of the materials and components mainly used in the unitized regenerative fuel cell (URFC) system. URFC is a viable energy storage system owing to its high specific packaged and theoretical energy densities of 400–1000 Wh/kg and 3660 Wh/kg, respectively. Nevertheless, during the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), the stability and durability of the URFC unit cell was severely affected by various degradation factors in the stacked cell. The certain issues are related to the (i) electrocatalysts (high cost, aggregation, migration, and supportive material corrosion), (ii) dissolution and cracks in the Nafion binder, (iii) physical degradation and higher cost of polymer membrane, and severe carbon corrosion in (iv) gas diffusion packing and (v) bipolar plates. Among these factors, the critical challenges are the severe carbon corrosion and durability of the membrane in the unit cell regions. The degradation occurs in the supporting material of the electrocatalyst, gas diffusion packing, and bipolar plate owing to carbon corrosion because of the high applied potential in the water electrolyzer mode. Recent developments are significantly enhancing the durability and overcoming the limitations in the URFC system. In this comprehensive review, we have pointed out the limitations, challenges, and critical developments in URFC systems. Furthermore, built on our experimental and intellectual awareness in the context of URFC system developments, new strategies have been suggested to prepare novel structured materials and composites for advanced URFC applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> URFC is an optimum fuel cell system owing to its specific high energy density. </LI> <LI> Critical problem is severe carbon corrosion in electrocatalyst support and GDB, BP. </LI> <LI> Major challenges are cost and durability of the membrane and electrode assembly. </LI> <LI> Highly crystalline of Gr-carbon can be considered as a corrosion-resistant material. </LI> <LI> Novel structured and low cost materials are most promising to advanced URFC system. </LI> </UL> </P>

High charge acceptance through interface reaction on carbon coated negative electrode for advanced lead-carbon battery system

Sadhasivam, T.,Park, Mi-Jung,Shim, Jin-Yong,Jin, Jae-Eun,Kim, Sang-Chai,Kurkuri, Mahaveer D.,Roh, Sung-Hee,Jung, Ho-Young Elsevier 2019 ELECTROCHIMICA ACTA Vol.295 No.-

<P><B>Abstract</B></P> <P>In this research, the interfacial effect between the carbon layer and the negative electrode surface is evaluated as a hybrid electrode with higher charge acceptance for the advanced lead-carbon battery (ALC-battery) system. The P-60 (activated carbon) material, with high specific surface area (1787 m<SUP>2</SUP> g<SUP>−1</SUP>) and higher electrical conductivity (98.85 S cm<SUP>−1</SUP>), is considered an efficient activated carbon in the present investigations and deposited on the negative electrode. Compared to the conventional lead-acid battery system, the carbon coated negative electrode of ALC-battery system exhibited higher capacity at the applied higher charge/discharge current. The efficient performance of the ALC-battery is mainly influenced by the thin layer of carbon on the active electrode surface, which induces higher charge acceptance. Furthermore, the ALC-battery showed an outstanding lifespan performance compared to the conventional lead-acid battery system in long-term operations. The resulting cycle life stability of lead-acid battery and ALC-battery is 2230 and 6780 cycles, respectively. The significant performance of the ALC-battery is mainly attributed by synergistic mechanism in hybrid electrode, which is resulted from interfacial effect. The likely synergetic reactions arises by carbon layer is (i) higher charge acceptance, (ii) controlled the formation of PbSO<SUB>4</SUB> crystallite in the electrode surfaces, (iii) improved electrochemical performances and Pb redox reaction due to higher electrical conductivity properties. Thus, it can be concluded that the carbon layer deposited on the negative electrode in the ALC-battery is an efficient approach for energy storage, with increased power, capacity, and enhanced cycle life stability.</P> <P><B>Highlights</B></P> <P> <UL> <LI> ALC-battery can be effectively considered for Idle Stop and Go vehicles. </LI> <LI> Synergistic effect in negative electrode enhances the ALC-battery performances. </LI> <LI> Charge acceptance of the battery is increased by carbon layer on negative electrode. </LI> <LI> Carbon layer can control the formation of larger PbSO<SUB>4</SUB> on surface of the electrode. </LI> <LI> Lifespan of ALC-battery is 3 times higher than conventional lead-acid battery. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Graphitized carbon as an efficient mesoporous layer for unitized regenerative fuel cells

Sadhasivam, T.,Roh, S.H.,Kim, T.H.,Park, K.W.,Jung, H.Y. Pergamon Press ; Elsevier Science Ltd 2016 International journal of hydrogen energy Vol.41 No.40

<P>To enhance the electrochemical performance of membrane electrode assemblies (MEAs) for unitized regenerative fuel cells (URFCs), we prepared and introduced graphitized-carbon (Gr-carbon) of high crystallinity as a mesoporous layer (MPL) in MEAs. The round-trip energy conversion efficiencies (epsilon(RT) (%)) of non-MPL, typical amorphous-carbon (Am carbon) MPL and Gr-carbon MPL containing MEAs at the current density of 1 A cm(-2) were 36.6, 41.8, and 43.8, respectively. The overall round trip energy efficiency was considerably higher for the graphitized form of mesoporous carbon. For Gr-carbon, a high stability of the round-trip energy conversion efficiency was achieved even after 20th cycles (42.3%) owing to the enhanced electrical conductivity and high crystallinity of Gr-carbon after thermal treatment. Therefore, Gr-carbon considerably enhances the ORR and OER performances and prevents carbon corrosion and surface oxidation during the fuel cell and water electrolyzer modes in the URFC system. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.</P>

Sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) membrane modified for long-term operating VRFB(Vanadium Redox flow battery)

이정명,( T. Sadhasivam ),임민화,문건오,박미정,노현준,정호영 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.0

Recently, redox flow battery (RFB) in energy storage system with high-capacity has been actively reseaching and developing. Economical hydrocarbon membranes alternative to fluorinated membranes for RFB membrane are receiving attention. In this study, characteristics of sulfonated poly(phenylene oxide) (sPPO) were compared with expensive fluorinated membrane at VRFB (Vanadium Redox Flow Battery) unit cell operation condition. Permeability of vanadium ion through membrane, ion exchange capacity (IEC), change of OCV, swelling, charge-discharge curves and energy efficiency were measured. sPPO membrane showed lower permeability of vanadium ion, higher IEC and then higher energy efficiency compared with Nafion 212 membranes.

Novel core–shell structure of a lead-activated carbon (Pb@AC) for advanced lead–acid battery systems

Dhanabalan, K.,Sadhasivam, T.,Kim, S. C.,Eun, J. J.,Shim, J.,Jeon, D.,Roh, S. H.,Jung, H. Y. Chapman and Hall 2017 Journal of materials science Materials in electron Vol. No.

<P>To enhance the power and energy densities of advanced lead-acid batteries (Ad-LAB), a novel core-shell structure of lead-activated carbon (Pb@AC) was prepared and used as a negative electrode active material. The AC could be formed as a shell around a core of Pb nanoparticles. The active core-shell structures were synthesized using a simple chemical process to overcome the limitations in the negative Pb electrode, specifically the large crystallization of lead sulfate (PbSO4) that leads to a short cycle life. The key role of the carbon material in the negative electrode is to enhance the electrochemical performances and decrease the formation of PbSO4. The X-ray diffraction study reveals that the formation of lead oxide was prevented by the AC during the synthetic process. The novel core-shell structure of Pb@AC was confirmed through transmission electron microscopy. In order to obtain high-performance Ad-LAB, a high surface area of the AC is necessary to provide a super capacitive effect in the negative electrode. The unit cell performance of the as-prepared active materials exhibits significant increased discharge capacity at 1C rate. The unit cell with the Pb@AC negative electrode has a capacity per unit volume of 0.0165 Ah/cc. Hence, the low cost of AC and the simple synthetic core-shell structure of Pb@AC make this material a promising negative electrode active material for Ad-LAB applications.</P>

Carbon free SiO₂-SO₃H supported Pt bifunctional electrocatalyst for unitized regenerative fuel cells

Roh, S.H.,Sadhasivam, T.,Kim, H.,Park, J.H.,Jung, H.Y. Pergamon Press ; Elsevier Science Ltd 2016 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.41 No.45

<P>The electrochemical performance of sulfonated silica-supported Pt electrocatalyst investigated as a bifunctional oxygen electrode for unitized regenerative fuel cell (URFC) system. The measured electrochemical surface area values are 23.02 and 22.96 m(2) g(-1) for the Pt black and 80 wt% Pt/SiO2-SO3H catalysts, respectively. The silica support is not prohibiting the electrical conductivity of Pt in the Pt/SiO2-SO3H electrocatalyst due to the high loading of Pt on the supporter. The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in the fuel cell and water electrolyzer modes were carried out in a unit cell for the Pt/C, Pt/SiO2, and Pt/SiO2-SO3H electrocatalysts. The Pt/SiO2-SO3H catalyst is exhibit better performance in oxygen reduction (hydrogen oxidation) and oxygen evolution (hydrogen evolution) reactions during cyclic processing due to the high proton conductivity of the sulfonated silica supporter. This result means that the sulfonic acid functional group on the support material (SiO2-SO3H) enhances proton conduction in the catalyst layer. Therefore, the ohmic resistance is decrease in the unit cell. Hence, the sulfonated silica supported Pt electrocatalyst is a bifunctional electrocatalyst candidate that can be used in the operation of a URFC. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.</P>