Hierarchical 3D ZnIn₂S₄/graphene nano-heterostructures: their <i>in situ</i> fabrication with dual functionality in solar hydrogen production and as anodes for lithium ion batteries

Kale, Sayali B.,Kalubarme, Ramchandra S.,Mahadadalkar, Manjiri A.,Jadhav, Harsharaj S.,Bhirud, Ashwini P.,Ambekar, Jalinder D.,Park, Chan-Jin,Kale, Bharat B. The Royal Society of Chemistry 2015 Physical Chemistry Chemical Physics Vol.17 No.47

<P>Hierarchical 3D ZnIn2S4/graphene (ZnIn2S4/Gr) nano-heterostructures were successfully synthesized using an in-situ hydrothermal method. The dual functionality of these nano-heterostructures i.e. for solar hydrogen production and lithium ion batteries has been demonstrated for the first time. The ZnIn2S4/Gr nano-heterostructures were optimized by varying the concentrations of graphene for utmost hydrogen production. An inspection of the structure shows the existence of layered hexagonal ZnIn2S4 wrapped in graphene. The reduction of graphene oxide (GO) to graphene was confirmed by Raman and XPS analyses. The morphological analysis demonstrated that ultrathin ZnIn2S4 nanopetals are dispersed on graphene sheets. The optical study reveals the extended absorption edge to the visible region due to the presence of graphene and hence is used as a photocatalyst to transform H2S into eco-friendly hydrogen using solar light. The ZnIn2S4/Gr nano-heterostructure that is comprised of graphene and ZnIn2S4 in a weight ratio of 1 : 99 exhibits enhanced photocatalytically stable hydrogen production i.e. B6365 mmole h(-1) under visible light irradiation using just 0.2 g of nano-heterostructure, which is much higher as compared to bare hierarchical 3D ZnIn2(S4). The heightened photocatalytic activity is attributed to the enhanced charge carrier separation due to graphene which acts as an excellent electron collector and transporter. Furthermore, the usage of nano-heterostructures and pristine ZnIn2S4 as anodes in lithium ion batteries confers the charge capacities of 590 and 320 mA h g(-1) after 220 cycles as compared to their initial reversible capacities of 645 and 523 mA h g(-1), respectively. These nano-heterostructures show high reversible capacity, excellent cycling stability, and high-rate capability indicating their potential as promising anode materials for LIBs. The excellent performance is due to the nanostructuring of ZnIn2S4 and the presence of a graphene layer, which works as a channel for the supply of electrons during the charge-discharge process. More significantly, their dual functionality in energy generation and storage is quite unique and commendable.</P>

Surfactant-assisted morphological tuning of hierarchical CuO thin films for electrochemical supercapacitors

Dubal, Deepak P.,Gund, Girish S.,Holze, Rudolf,Jadhav, Harsharaj S.,Lokhande, Chandrakant D.,Park, Chan-Jin The Royal Society of Chemistry 2013 Dalton Transactions Vol.42 No.18

<P>Copper oxide (CuO) thin films are successfully synthesized using a surfactant assisted chemical bath deposition method for application in supercapacitors. The effect of organic surfactants such as Triton X-100 and polyvinyl alcohol (PVA) on structural, morphological, surface areas and electrochemical properties of CuO thin films is investigated. The films deposited using organic surfactants exhibit different surface morphologies. It is observed that the organic surfactants play important roles in modifying the morphology, surface area and pore size distribution. Electrochemical analysis confirms that the nanostructures of the electrode material play a vital role in supercapacitors. The cyclic voltammetry studies show a considerably improved high rate pseudocapacitance of CuO samples synthesized using organic surfactants. The maximum specific capacitance of 411 F g<SUP>−1</SUP> at 5 mV s<SUP>−1</SUP> is obtained for the CuO sample prepared using an organic surfactant (Triton X-100). Furthermore, all the CuO nanostructures exhibit high power performance, excellent rate as well as long term cycling stability. The Ragone plot ascertains better power and energy densities of CuO nanostructured samples. This is an easy and simple way to tune the morphology using surfactants which can be applied for other energy storage materials.</P> <P>Graphic Abstract</P><P>Copper oxide (CuO) thin films are successfully synthesized using a surfactant assisted chemical bath deposition method for application in supercapacitors. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c3dt50275a'> </P>

Hierarchical free-standing networks of MnCo2S4 as efficient Electrocatalyst for oxygen evolution reaction

Harsharaj S. Jadhav,ROY ANIMESH,Gaurav M. Thorat,정욱진,서정길 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.71 No.-

The development of highly efficient, stable and cost-effective electrocatalyst for oxygen evolutionreaction (OER) is critical. Herein, we report growth of MnCo2S4 flakes on SS-mesh using two-stepstrategy, and used as an efficient, highly active and stable electrocatalyst for OER under alkalinecondition. The free-standing electrocatalyst delivers exceptional stability of 100 h and activity for OERwith overpotential of 290 mV at a current density of 10 mA cm 2 in 1 M KOH. The enhancedelectrocatalytic performance was supported experimentally by electrochemical impedance spectra andmeasurement of the electrochemically active surface area. The high electrochemical active surface areaand electrical conductivity of MnCo2S4 flakes played an essential role in their high electrocatalyticperformance.

Mesoporous Mn₂O₃/reduced graphene oxide (rGO) composite with enhanced electrochemical performance for Li-ion battery

Jadhav, Harsharaj S.,Thorat, Gaurav M.,Kale, Bharat B.,Seo, Jeong Gil Royal Society of Chemistry 2017 Dalton Transactions Vol. No.

<▼1><P>Transition metal oxides are the most promising candidates in low-cost and eco-friendly energy storage/conversion applications.</P></▼1><▼2><P>Transition metal oxides are the most promising candidates in low-cost and eco-friendly energy storage/conversion applications. Herein, bare Mn2O3 and a Mn2O3/reduced graphene oxide (rGO) composite have been synthesized by a facile chemical co-precipitation and subsequent annealing procedure. The synthesized Mn2O3/rGO composite exhibits a porous microcube structure formed with several interconnected particles. The porous Mn2O3/rGO composite, with high surface area and increased conductivity, facilited the charge transfer to enhance the overall electrochemical performance when applied as an anode material in Li-ion batteries. The porous Mn2O3/rGO composite exhibits a highly reversible lithium storage capacity of 1015 mA h g<SUP>−1</SUP> at a rate of 0.5 C (230 mA g<SUP>−1</SUP>) during 130 cycles with excellent cycling stability and rate capability. The superior electrochemical performance results mainly due to the combined effect of rGO and Mn2O3, which offers high conductivity, faster Li<SUP>+</SUP> ion transfer, and enhanced structural stability. The material synthesis strategy presented in this study is simple, cost-effective and scalable, which can open new avenues for large-scale applications of composites of graphene and other transition metal oxides.</P></▼2>

Iron-nickel spinel oxide as an electrocatalyst for non-aqueous rechargeable lithium-oxygen batteries

Jadhav, Harsharaj S.,Kalubarme, Ramchandra S.,Jadhav, Arvind H.,Seo, Jeong Gil Elsevier 2016 Journal of Alloys and Compounds Vol.666 No.-

<P><B>Abstract</B></P> <P>A lithium-oxygen (Li–O<SUB>2</SUB>) battery requires effective catalyst to enable oxygen reduction and evolution. Herein, we report the synthesis of novel macroporous NiFe<SUB>2</SUB>O<SUB>4</SUB> nanoparticles by a facile and cost-effective urea assisted co-precipitation process. Characterization of the catalysts by X-ray diffraction and transmission electron microscopy confirms the formation of a single phase NiFe<SUB>2</SUB>O<SUB>4</SUB> structure. The use of macroporous NiFe<SUB>2</SUB>O<SUB>4</SUB> particles as oxygen electrode catalyst in rechargeable Li–O<SUB>2</SUB> batteries, exhibits a superior catalytic activity with high reversible capacity of 5940 mA h g<SUP>−1</SUP>. Additionally, catalytic activity results in low charge over potential and comparable discharge capacity and cycling stability, indicating its potential as a promising catalyst for Li–O<SUB>2</SUB> batteries. The simple and cost effective chemical co-precipitation method can be explored for synthesis of another oxides based catalyst materials.</P> <P><B>Highlights</B></P> <P> <UL> <LI> NiFe<SUB>2</SUB>O<SUB>4</SUB> synthesized by simple and cost effective chemical co-precipitation method. </LI> <LI> NiFe<SUB>2</SUB>O<SUB>4</SUB> is used as active catalyst in oxygen electrode for Li-air battery. </LI> <LI> Present Li-O<SUB>2</SUB> batteries can exhibit reasonable specific capacity and cyclability. </LI> <LI> Easy, scale-up co-precipitation method can be explored for other oxide materials. </LI> </UL> </P>

B₂O₃-added lithium aluminium germanium phosphate solid electrolyte for Li–O₂ rechargeable batteries

Jadhav, Harsharaj S.,Kalubarme, Ramchandra S.,Jang, Seong-Yong,Jung, Kyu-Nam,Shin, Kyoung-Hee,Park, Chan-Jin The Royal Society of Chemistry 2014 Dalton Transactions Vol.43 No.30

<P>B<SUB>2</SUB>O<SUB>3</SUB>-added Li<SUB>1.5</SUB>Al<SUB>0.5</SUB>Ge<SUB>1.5</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB> (LAGP) glass ceramics showing a room temperature ionic conductivity of 0.67 mS cm<SUP>−1</SUP> have been synthesized by using a melt-quenching method. The prepared glass ceramics are observed to be stable in tetraethylene glycol dimethyl ether containing lithium bis(trifluoromethane) sulfonamide. The augmented conductivity of the B<SUB>2</SUB>O<SUB>3</SUB>-added LAGP glass ceramic has improved the plateau potential during discharge. Furthermore, the B<SUB>2</SUB>O<SUB>3</SUB>-added LAGP glass ceramics are successfully employed as a solid electrolyte in a Li–O<SUB>2</SUB> battery to obtain a stable cycling lifetime of up to 15 cycles with the limited capacity protocol.</P> <P>Graphic Abstract</P><P>B<SUB>2</SUB>O<SUB>3</SUB>-added Li<SUB>1.5</SUB>Al<SUB>0.5</SUB>Ge<SUB>1.5</SUB>(PO<SUB>4</SUB>)<SUB>3</SUB> (LAGP) glass ceramics showing a room temperature ionic conductivity of 0.67 mS cm<SUP>−1</SUP> have been synthesized by using a melt-quenching method. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c4dt01144a'> </P>

Hierarchical free-standing networks of MnCo₂S₄ as efficient Electrocatalyst for oxygen evolution reaction

Jadhav, Harsharaj S.,Roy, Animesh,Thorat, Gaurav M.,Chung, Wook-Jin,Seo, Jeong Gil Elsevier 2019 Journal of industrial and engineering chemistry Vol.71 No.-

<P><B>Abstract</B></P> <P>The development of highly efficient, stable and cost-effective electrocatalyst for oxygen evolution reaction (OER) is critical. Herein, we report growth of MnCo<SUB>2</SUB>S<SUB>4</SUB> flakes on SS-mesh using two-step strategy, and used as an efficient, highly active and stable electrocatalyst for OER under alkaline condition. The free-standing electrocatalyst delivers exceptional stability of 100h and activity for OER with overpotential of 290mV at a current density of 10mAcm<SUP>−2</SUP> in 1M KOH. The enhanced electrocatalytic performance was supported experimentally by electrochemical impedance spectra and measurement of the electrochemically active surface area. The high electrochemical active surface area and electrical conductivity of MnCo<SUB>2</SUB>S<SUB>4</SUB> flakes played an essential role in their high electrocatalytic performance.</P> <P><B>Highlights</B></P> <P> <UL> <LI> MnCo<SUB>2</SUB>S<SUB>4</SUB> have been synthesized by electrodeposition followed by sulfidation. </LI> <LI> Electrocatalyst exhibits overpotential of 290mV at a 10mA/cm<SUP>2</SUP> current density. </LI> <LI> Large ECSA with plenty active sites deliver exceptional stability of 100h. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>The free-standing electrocatalyst demonstrates superior activity over that of a oxide catalyst, with the need of an overpotential of 290mV to drive a geometrical catalytic current density of 10mAcm<SUP>−2</SUP> in 1M KOH, which is superior to earlier report of MnCo<SUB>2</SUB>S<SUB>4</SUB>.</P> <P>[DISPLAY OMISSION]</P>

Facile and Cost Effective Synthesized Mesoporous Spinel NiCo₂O₄ as Catalyst for Non-Aqueous Lithium-Oxygen Batteries

Jadhav, Harsharaj S.,Kalubarme, Ramchandra S.,Roh, Jang-Woong,Jung, Kyu-Nam,Shin, Kyoung-Hee,Park, Choong-Nyeon,Park, Chan-Jin The Electrochemical Society 2014 Journal of the Electrochemical Society Vol.161 No.14

<P>The electrochemical performance of lithium-oxygen batteries can be significantly improved by employing a suitable catalyst to enhance the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Herein, a versatile, effective and economic co-precipitation synthesis of spinel NiCo<SUB>2</SUB>O<SUB>4</SUB> with an urchin-like structure has been reported as an electrocatalyst for rechargeable non-aqueous Li-O<SUB>2</SUB> batteries. The spherical urchin-like structure of spinel NiCo<SUB>2</SUB>O<SUB>4</SUB> was formed without the use of any template or surfactant. The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) kinetics in the Li-O<SUB>2</SUB> batteries could be drastically improved by employing the effective NiCo<SUB>2</SUB>O<SUB>4</SUB> catalyst, achieving a higher discharge potential and rate. In particular, the urchin-like structure of the catalyst not only provides more electrocatalytic sites but also promotes mass transport in the electrolyte. In addition, mesoporous NiCo<SUB>2</SUB>O<SUB>4</SUB> can efficiently catalyze the formation and decomposition of Li<SUB>2</SUB>O<SUB>2</SUB>. The Li-O<SUB>2</SUB> battery containing the urchin-like NiCo<SUB>2</SUB>O<SUB>4</SUB> catalyst exhibited the highest specific capacity of about 7309 mA h g<SUP>−1</SUP> at 0.2 mA cm<SUP>−2</SUP>. The integrity and porosity of spinel NiCo<SUB>2</SUB>O<SUB>4</SUB> had a significant effect on the performance of the Li-O<SUB>2</SUB> battery with reasonable specific capacity and cyclability, suggesting that the NiCo<SUB>2</SUB>O<SUB>4</SUB>-based materials can be effective catalysts for oxygen electrode in high performance Li-O<SUB>2</SUB> batteries.</P>

Facile and cost effective synthesis of mesoporous spinel NiCo2O4 as an anode for high lithium storage capacity.

Jadhav, Harsharaj S,Kalubarme, Ramchandra S,Park, Choong-Nyeon,Kim, Jaekook,Park, Chan-Jin RSC Pub 2014 Nanoscale Vol.6 No.17

<P>To fulfill the high power and high energy density demands for Li-ion batteries (LIBs) new anode materials need to be explored to replace conventional graphite. Herein, we report the urea assisted facile co-precipitation synthesis of spinel NiCo2O4 and its application as an anode material for LIBs. The synthesized NiCo2O4 exhibited an urchin-like microstructure and polycrystalline and mesoporous nature. In addition, the mesoporous NiCo2O4 electrode exhibited an initial discharge capacity of 1095 mA h g(-1) and maintained a reversible capacity of 1000 mA h g(-1) for 400 cycles at 0.5 C-rate. The reversible capacity of NiCo2O4 could still be maintained at 718 mA h g(-1), even at 10 C. The mesoporous NiCo2O4 exhibits great potential as an anode material for LIBs with the advantages of unique performance and facile preparation.</P>

Growth of urchin-like ZnCo₂O₄ microspheres on nickel foam as a binder-free electrode for high-performance supercapacitor and methanol electro-oxidation

Jadhav, Harsharaj S.,Roy, Animesh,Chung, Wook-Jin,Seo, Jeong Gil Elsevier 2017 ELECTROCHIMICA ACTA Vol.246 No.-

<P><B>Abstract</B></P> <P>The spinel-type transition metal oxides play key role in realizing cost-effective energy storage systems by exhibiting outstanding electrochemical activity and stability. Free standing 3D hierarchical mesoporous ZnCo<SUB>2</SUB>O<SUB>4</SUB> microspheres are grown on nickel foam (NF) substrate using hydrothermal route followed by annealing treatment. 3D hierarchical mesoporous ZnCo<SUB>2</SUB>O<SUB>4</SUB> microspheres with high surface area and uniform mesoporous distribution exhibits high electrochemical performance. The ZnCo<SUB>2</SUB>O<SUB>4</SUB>/NF electrode material deliver superior specific capacitance of 1143Fg<SUP>−1</SUP> at a current density of 1.25Ag<SUP>−1</SUP> in aqueous 2M KOH solution and exhibits long-term cycling stability with specific capacitance of 880Fg<SUP>−1</SUP> after 6000 cycles at 12.5Ag<SUP>−1</SUP>. Furthermore, ZnCo<SUB>2</SUB>O<SUB>4</SUB>/NF electrode maintains current density upto 105Ag<SUP>−1</SUP> in 1M KOH mixed with 0.5M methanol when applied as electro-catalyst for methanol electro-oxidation. The high electrochemical performance is mainly attributed to faster ion/electron transfer and an enhanced electrochemical kinetics. The present simple, and cost-effective synthesis approach can open new era for large-scale applications of the novel materials for different electrochemical applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Urchin-like 3D ZnCo<SUB>2</SUB>O<SUB>4</SUB> directly grown on nickel foam by hydrothermal route. </LI> <LI> ZnCo<SUB>2</SUB>O<SUB>4</SUB> electrode shows superior electrochemical performance for supercapacitor. </LI> <LI> First report on ZnCo<SUB>2</SUB>O<SUB>4</SUB> use as an electro-catalyst for methanol electro-oxidation. </LI> <LI> ZnCo<SUB>2</SUB>O<SUB>4</SUB> possess high surface area with uniform mesoporous pore size distribution. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>