Selective design of binder-free hierarchical nickel molybdenum sulfide as a novel battery-type material for hybrid supercapacitors

Manikandan, Ramu,Raj, C. Justin,Nagaraju, Goli,Pyo, Myoungho,Kim, Byung Chul The Royal Society of Chemistry 2019 Journal of Materials Chemistry A Vol.7 No.44

<P>Recently, binder-free and hierarchical electrode materials have attracted special attention for the rational design of high-energy density hybrid supercapacitors. Herein, we demonstrated binder-free nickel molybdenum sulfide nano-flakes on nickel foam (NMS-Ni) using a facile successive ionic layer adsorption and reaction (SILAR) process for the fabrication of high-performance hybrid supercapacitors. The selective SILAR cycles had a significant effect on the morphology and electrochemical properties of the NMS nanostructures. Specifically, the NMS deposited for 40 cycles (40cyc@NMS-Ni) displayed the maximum areal capacity (<I>C</I>Ac) of 2.8 C cm<SUP>−2</SUP> (2224 C g<SUP>−1</SUP>) at the current density 4 mA cm<SUP>−2</SUP> in a 6 M KOH electrolyte. Furthermore, a hybrid supercapacitor (HSC) was fabricated using 40cyc@NMS-Ni as the positive electrode and N,O-enriched activated carbon (N,O-AC)-coated Ni-foam as the negative electrode, which showed the maximum potential and specific capacitance (<I>C</I>F-cell) of 1.5 V and 111 F g<SUP>−1</SUP>, respectively. Moreover, the device displayed an outstanding specific energy and specific power of 35 W h kg<SUP>−1</SUP> and 1.5 kW kg<SUP>−1</SUP> with an excellent capacitance retention (95%) after 5000 cycles, respectively. Thus, based on the observed results, it can be concluded that the present study demonstrates a route to utilize NMS-based electrodes as a promising material for high-performance energy storage devices.</P>

1P-375 Na_xV₂O₅ Nano Composite for High-Performance Symmetric Pseudocapacitor

( Ramu Manikandan ),박승일,( Murugesan Rajesh ),유국현 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1

Symmetric supercapacitor was fabricated using NaxV₂O₅ nanocomposite synthesized via a conventional co-precipitation technique. The structural and morphological investigation showed that the synthesized Na_xV₂O₅ sample exhibited good crystallinity with nanorod stacked morphology. The electrochemical properties of the Na_xV₂O₅ symmetric supercapacitor was performed in 1M Na₂SO₄ aqueous electrolyte. The fabricated Na_xV₂O₅ symmetric supercapacitors exhibited excellent electrochemical capacitance behavior with maximum specific capacitance value of 166 F g^-1 at 0.5 A g^-1. Moreover, Na_0.33V₂O₅ symmetric supercapacitors demonstrated an excellent cyclic stability with a high capacitance retention of ~87% after 50,000 charge/ discharge cycles.

Low temperature synthesis of Na_0.33V₂O₅ and their Li⁺ ion supercapacitive behavior

( Ramu Manikandan ),( Murugesan Rajesh ),박승일,( C. Justin Raj ),김병철,유국현 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1

The sodium vanadium oxide exists in several forms NaV₆O₁₅, NaVO₂, NaVO₃ and NaV₃O₈. In this present work, we prepared Na_0.33V₂O₅ nanostructure by simple co-precipitation technique at low temperature (80℃) using VOSO_4.xH₂O and NaOH solution. The structural and morphological properties of Na_0.33V₂O₅ were studied using XRD, Raman spectrum and SEM analysis. The Li+ ion supercapacitive behavior of the Na_0.33V₂O₅ electrode was investigated by means of CV, GCD technique and EIS in 1M LiClO₄ electrolyte. The Na_0.33V₂O₅ electrode showed maximum capacitance of 164 F g^-1 at 1A g^-1.

Improved Electrochemical Performance of Fe3O4 Nanoparticles Decorated Activated Carbon Supercapacitor Electrodes

박승일,저스틴라즈,RAMU MANIKANDAN,김병철,유국현 대한화학회 2020 Bulletin of the Korean Chemical Society Vol.41 No.8

Metal oxide decorated activated carbon (AC) composites exhibit excellent electrochemical property and which is potential for energy storage and catalytic applications. Here, we report the synthesis of iron oxide (Fe3O4) anchored AC composite for supercapacitor (SC) electrode. The citrate-stabilized Fe3O4 aqueous dispersion (5 mg/mL) of various concentration was utilized for the functionalization of commercial AC and the sample prepared using 50?mL Fe3O4 aqueous dispersion in 2 g of AC (AC-50Fe) displayed better surface morphology with comparable surface area and porosity. Moreover, the sample AC-50Fe showed excellent electrochemical performance with a maximum specific capacitance value 131?Fg?1 and cyclic stability ?105% after 10 000 charge/discharge cycles, which is much higher than the bare AC (77?Fg?1) and AC-25Fe (91?Fg?1) electrodes. Thus, the optimum amount of Fe3O4 in AC can effectively enhance the SC performance of the electrode by supplying additional pseudocapacitance along with the electric double-layer capacitance of AC.

Efficient supercapattery behavior of mesoporous hydrous and anhydrous cobalt molybdate nanostructures

Kim, Byung Chul,Manikandan, Ramu,Yu, Kook Hyun,Park, Myung-Soo,Kim, Dong-Won,Park, Sang Yeup,Justin Raj, C. Elsevier 2019 JOURNAL OF ALLOYS AND COMPOUNDS Vol.789 No.-

<P><B>Abstract</B></P> <P>Hydrous forms of cobalt molybdate binary metal oxide nanoaggregates were synthesized via a simple chemical co-precipitation technique. The subsequent heat treatment at 400 <SUP>°</SUP>C converted the sample into anhydrous cobalt molybdate (CoMoO<SUB>4</SUB>) with mesoporous nanostructure. The anhydrous cobalt molybdate possess surface area and pore volume of 63.92 m<SUP>2</SUP>g<SUP>-1</SUP> and 0.1802 cm<SUP>3</SUP>g<SUP>-1</SUP> which is much higher than the hydrous cobalt molybdate (1.215 m<SUP>2</SUP>g<SUP>-1</SUP> and 0.0072 cm<SUP>3</SUP> g<SUP>−1</SUP>). The electrodes designed using these materials exhibited a battery-like behavior with maximum specific capacity of 97 Cg<SUP>-1</SUP> and 177 Cg<SUP>-1</SUP> for hydrous and anhydrous cobalt molybdate samples respectively. In addition, a supercapattery was fabricated utilizing anhydrous cobalt molybdate//activated carbon electrodes, which showed maximum specific capacity value of 64 Cg<SUP>-1</SUP> at 1 Ag<SUP>-1</SUP> discharge specific current and showed better specific energy ∼18.89 Whkg<SUP>−1</SUP> for a specific power of 1.06 kWkg<SUP>−1</SUP>. Moreover, the supercapattery exhibited good capacity retention ∼93% after 5000 charge/discharge cycles.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hydrous and anhydrous cobalt molybdate mesoporous nanostructures were synthesized. </LI> <LI> The electrodes exhibited non-capacitive faradaic charge storage mechanism. </LI> <LI> The anhydrous CoMoO<SUB>4</SUB> electrode shows improved structural, morphological and electrochemical properties. </LI> <LI> The supercapattery designed using the electrode displayed excellent performances. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Citric acid stabilized iron oxide nanoparticles for battery- type supercapacitor electrode

Seungil Park,C. Justin Raj,Ramu Manikandan,Byung Chul Kim,Kook Hyun Yu 한양대학교 세라믹연구소 2020 Journal of Ceramic Processing Research Vol.21 No.2

We report the synthesis of citrate stabilized iron oxide (C-Fe3O4) spherical nanoparticles for supercapacitor electrodes. Thecitrate functional group present in the surface of the Fe3O4 nanoparticles effectively controls the morphology and the surfacearea of the nanostructures. The C-Fe3O4 electrodes exhibited a battery-like energy storage properties with a maximum specificcapacity of 146 Cg−1 (242 Fg−1) which is much higher than the specific capacity of citrate free Fe3O4 electrode (62 Cg−1; 112Fg−1). Moreover, the C-Fe3O4 electrode showed better cyclic stability (75%) than the citrate free Fe3O4 electrode (~35%) after1000 charge/discharge cycles.

High electrochemical capacitor performance of oxygen and nitrogen enriched activated carbon derived from the pyrolysis and activation of squid gladius chitin

Raj, C. Justin,Rajesh, Murugesan,Manikandan, Ramu,Yu, Kook Hyun,Anusha, J.R.,Ahn, Jun Hwan,Kim, Dong-Won,Park, Sang Yeup,Kim, Byung Chul Elsevier 2018 Journal of Power Sources Vol.386 No.-

<P><B>Abstract</B></P> <P>Activated carbon containing nitrogen functionalities exhibits excellent electrochemical property which is more interesting for several renewable energy storage and catalytic applications. Here, we report the synthesis of microporous oxygen and nitrogen doped activated carbon utilizing chitin from the gladius of squid fish. The activated carbon has large surface area of 1129 m<SUP>2</SUP> g<SUP>−1</SUP> with microporous network and possess ∼4.04% of nitrogen content in the form of pyridinic/pyrrolic-N, graphitic-N and N-oxide groups along with oxygen and carbon species. The microporous oxygen/nitrogen doped activated carbon is utilize for the fabrication of aqueous and flexible supercapacitor electrodes, which presents excellent electrochemical performance with maximum specific capacitance of 204 Fg<SUP>−1</SUP> in 1 M H<SUB>2</SUB>SO<SUB>4</SUB> electrolyte and 197 Fg<SUP>−1</SUP> as a flexible supercapacitor. Moreover, the device displays 100% of specific capacitance retention after 25,000 subsequent charge/discharge cycles in 1 M H<SUB>2</SUB>SO<SUB>4</SUB> electrolyte.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A novel O- and N- doped activated carbon is derived from squid gladius chitin. </LI> <LI> The microporous carbon is used for the fabrication of supercapacitor electrodes. </LI> <LI> The supercapacitors demonstrated remarkable electrochemical performances. </LI> <LI> The device shows long stability of ∼100% after 25,000 charge/discharge cycles. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>