제조공정에 따른 MnO₂산화물 전극의 전기화학적 특성

김현식,이해연,허정섭,이동윤 한국전기전자재료학회 2004 전기전자재료학회논문지 Vol.17 No.5

Dimensionally stable anode(DSA) can be used for the hydro-metallurgy of non-ferrous metals like as Zn, and the electrolysis of sea water. MnO$_2$ electrode satisfies the requirements of DSA, and has a good cycle life and a low overpotential for oxygen evolution. MnO$_2$ electrodes based on Ti matrix were prepared by using thermal decomposition method and also MnO$_2$ was coated on Ti and Pb matrix with DMF and PVDF compositions. The MnO$_2$ electrodes prepared by thermal decomposition method had very weak adhesive strength onto Ti matrix and MnO$_2$ layer was removed out so that electrochemical properties for MnO$_2$ were not investigated. The viscosity of solvent used as a binder of MnO$_2$ Powder increased with the increasing PVDF contents. The thickness of the MnO$_2$ layer on Pb matrix in DSA, which was prepared with 5 times dipping at the solution mixed with PVDF : DMF = 1 : 9, was 150${\mu}{\textrm}{m}$. When the ratio of PVDF to MnO$_2$ was lower than 1 : 6, the Pb electrode didn't show any reaction irrespective of the concentrations of DMF. However, When the ratio of PVDF to MnO$_2$ was higher than 1: 6, the Pb electrode showed constant current reactions and homogeneous cyclic voltammetry even though at a high cycle. The reason for the high current and homogeneous cyclic voltammetry is the good catalytic reactions of MnO$_2$ powder in electrode.

Influence of rare earth elements on porosity controlled synthesis of MnO₂ nanostructures for supercapacitor applications

Rajagopal, Rajesh,Ryu, Kwang-Sun Pergamon Press 2018 Electrochimica Acta Vol. No.

<P><B>Abstract</B></P> <P>Nanostructured MnO<SUB>2</SUB> was synthesized using a facile hydrothermal technique with potassium permanganate as a precursor. Rare earth elements, lanthanum and cerium, were used to control the porosity of the MnO<SUB>2</SUB> nanostructures. Nanorod-, nanoflower-, nanoneedle-, and nanoneedles/nanopetal-shaped MnO<SUB>2</SUB> nanostructures were synthesized by changing the concentration of the rare earth elements. The as-synthesized MnO<SUB>2</SUB> nanorods, La – MnO<SUB>2</SUB> nanoneedles, Ce – MnO<SUB>2</SUB> nanoflowers, and La/Ce – MnO<SUB>2</SUB> nanoneedles/nanopetals were examined using a range of physico chemical characterization techniques. Scanning electron microscopy and transmission electron microscopy – energy dispersive X-ray spectroscopy confirmed the morphology of the MnO<SUB>2</SUB> nanostructures and the elemental distribution. The porous natures of the synthesized MnO<SUB>2</SUB> nanostructures were analyzed by nitrogen adsorption technique. The electrochemical behavior of the MnO<SUB>2</SUB> nanostructures was examined by cyclic voltammetry, charge – discharge and electrochemical impedance spectroscopy tests. The La/Ce – MnO<SUB>2</SUB> nanoneedles/nanopetals electrode exhibited a high specific capacitance of 825 F g<SUP>−1</SUP> at an applied current density of 10 A g<SUP>−1</SUP>. The La/Ce – MnO<SUB>2</SUB> nanoneedles/nanopetals were also mixed with 5, 10, 15 and 20 wt% of rGO nanosheets to enhance the electrochemical behavior. The 20 rGO@La/Ce – MnO<SUB>2</SUB> sample showed extraordinary electrochemical behavior; the calculated specific capacitance was 1165 F g<SUP>−1</SUP> at an applied current density of 10 A g<SUP>−1</SUP>. A 20 rGO@La/Ce – MnO<SUB>2</SUB> and activated carbon asymmetric supercapacitor coin cell device exhibited ∼93% capacitance retention after 1000 cycles. These results highlight the potential of 20 rGO@La/Ce – MnO<SUB>2</SUB> as an electrode material for supercapacitor applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Manganese oxide nanostructures were synthesized by hydrothermal process. </LI> <LI> Lanthanum and cerium used to control the porosity of manganese oxide. </LI> <LI> La/Ce mixed MnO<SUB>2</SUB> nanoneedles/nanopetals showing good electrochemical behavior. </LI> <LI> rGO mixed La/Ce – MnO<SUB>2</SUB> was prepared to improve the storage capacity. </LI> <LI> 20rGO@ La/Ce – MnO<SUB>2</SUB> electrode exhibited high specific capacitance of 1165 F g<SUP>−1</SUP>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Direct electro-synthesis of MnO₂ nanoparticles over nickel foam from spent alkaline battery cathode and its supercapacitor performance

Edison, Thomas Nesakumar Jebakumar Immanuel,Atchudan, Raji,Karthik, Namachivayam,Xiong, Dangsheng,Lee, Yong Rok Elsevier 2019 JOURNAL- TAIWAN INSTITUTE OF CHEMICAL ENGINEERS Vol.97 No.-

<P><B>Abstract</B></P> <P>This work reports the recovery of manganese ions from spent primary alkaline battery (PAB) cathode, subsequent anodic electro-synthesis of MnO<SUB>2</SUB> nanoparticles on Ni foam (MnO<SUB>2</SUB> NPs/Ni foam) for supercapacitors. The as-fabricated MnO<SUB>2</SUB> NPs/Ni foam is characterized by common optical and surface analytical techniques. The X-ray diffraction (XRD) of MnO<SUB>2</SUB> NPs/Ni foam matches well with γ-MnO<SUB>2</SUB> NPs pattern and hence the synthesized MnO<SUB>2</SUB> NPs mainly exist in γ-phase. The synthesized MnO<SUB>2</SUB> NPs are mostly in spherical cluster shape with an average size of 15 nm, inferred from the scanning electron microscopic (SEM) images. The X-ray photoelectron spectroscopy (XPS) result reveals that, synthesized MnO<SUB>2</SUB> NPs embraces with two different oxidation states such as 4<SUP>+</SUP> (MnO<SUB>2</SUB>) and 3<SUP>+</SUP> (MnOOH). The MnO<SUB>2</SUB> NPs/Ni foam delivers a maximum specific capacity of 549 F/g at the scan rate of 5 mV/s in three electrodes aqueous K<SUB>2</SUB>SO<SUB>4</SUB> system. Further, the two electrode asymmetric supercapacitor device is constructed with MnO<SUB>2</SUB> NPs/Ni foam as a positive and commercial graphene nanoplatelets coated Ni foam (GNP/Ni foam) as a negative electrode. The assembled supercapacitor device yields a maximum specific capacitance of 105 F/g at 5 mV/s, which achieves a maximum energy density of 14.7 Wh/kg at the power density of 748.9 W/kg between 0 and 1.5 V of working potential. This effort may pave the way for recovery and utilization of spent PAB cathode materials for energy storage devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> This work presents simple method for the recovery and utilization of Mn<SUP>2+</SUP> from spent alkaline battery cathode. </LI> <LI> The average size of the MnO<SUB>2</SUB> NPs was about 15 nm with spherical cluster shape. </LI> <LI> The electro-synthesized MnO<SUB>2</SUB> NPs revealed good electrochemical performance in K<SUB>2</SUB>SO<SUB>4</SUB>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Synthesis and Supercapacitor Characteristics of Hydrothermally-deposited MnO2 Films and Chemically Co-deposited MnO2-polyaniline Films on Stainless-steel Substrates

Patin Tagsin,Pawinee Klangtakai,Viyada Harnchana,Samuk Pimanpang,Vittaya Amornkitbamrung 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.66 No.12

MnO2 films were hydrothermally grown directly onto stainless-steel substrates and used as supercapacitor electrodes. MnO2 with a cube-like structure was observed by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The measured sizes of the cubes were in the range of 270 − 820 nm. The specific capacitance (SC) of the 5-hour hydrothermallygrown MnO2 films was 20.2 F/g, which was slightly higher than that of the 3-hour films (13.8 F/g). The low values of the SC of the hydrothermally-deposited MnO2 films are attributed to their high series resistances of 1.73 − 2.06 measured by using electrochemical impedance spectroscopy. However, the specific capacitance was greatly increased, up to 226 F/g, after a polyaniline polymer had been added into the MnO2 hydrothermal reaction, there by producing a composite of the MnO2 and the polyaniline polymer. This SC improvement was attributed to presence of two active materials (polyaniline and MnO2) and the reduction of the electrode series resistance to 0.93 .

Enhanced Specific Capacitance of an Electrophoretic Deposited MnO2-Carbon Nanotube Supercapacitor

Patin Tagsin,Pawinee Klangtakai,Viyada Harnchana,Vittaya Amornkitbamrung,Samuk Pimanpang,Pisist Kumnorkaew 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.71 No.12

MnO2 and MnO2-carbon nanotubes (CNT) composite films were grown directly on stainless- steel substrates using an electrophoretic process employing supercapacitor electrodes. An electrophoretic MnO2 film with a nanoplate-like structure was observed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Supercapacitor performance was studied using cyclic voltammetry (CV), charge-discharge (CD) and electrochemical impedance spectroscopy (EIS). The specific capacitance (SC) of the electrophoretic MnO2 film was 60 F/g at 1 A/g, with a 38.33% retention of the initial SC values after 1000 cycles. The low SC value of the MnO2 films was attributed to the high series and charge-transfer resistances of 1.70 and 3.20, respectively. The MnO2-CNT composites with the addition of 0.04, 0.06 and 0.08 g CNT to the electrophoretic MnO2 film were found to greatly increase the SC to 300, 206 and 169 F/g at 1 A/g, respectively. The series and charge-transferred resistances of MnO2-CNT composite films decreased to 1.38 - 1.52 and 2.62 - 2.86 , respectively. The SC improvement of the composite electrodes was attributed to presence of two active storage materials (MnO2 and CNT), a high film specific surface area and electrical conductivity.

Low-cost superior symmetric solid-state supercapacitors based on MWCNTs/MnO₂ nanocomposite thin film

Chodankar, Nilesh R.,Ji, Su-Hyeon,Kim, Do-Heyoung Elsevier 2017 JOURNAL- TAIWAN INSTITUTE OF CHEMICAL ENGINEERS Vol.80 No.-

<P><B>Abstract</B></P> <P>Herein we developed a nanocomposite of MnO<SUB>2</SUB> and multiwall carbon nanotubes (MWCNTs) deposited on a stainless-steel mesh substrate using a simple and scalable chemical approach to greatly expand the capacitive performance of MnO<SUB>2</SUB>-based electrodes. Electrochemical investigations of the chemically prepared MWCNTs/MnO<SUB>2</SUB> nanocomposite showed that it has high specific capacitance (614 F/g), high specific energy (85.3 Wh/kg), and high stability over 2500 cycles. The enhanced capacitive performance of the MWCNTs/MnO<SUB>2</SUB> nanocomposite was analyzed by calculating the surface-controlled and diffusion-controlled charge components. A symmetric solid-state supercapacitor using a MWCNTs/MnO<SUB>2</SUB> nanocomposite electrode and polyvinyl alcohol (PVA)-Na<SUB>2</SUB>SO<SUB>4</SUB> gel electrolyte achieved a cell voltage of 1.0 V and a maximum specific capacitance of 204 F/g with an energy density of 28.33 Wh/kg. Furthermore, the assembled symmetric solid-state supercapacitor achieved coulombic efficiency of 99.04%. The excellent electrochemical features of the MWCNTs/MnO<SUB>2</SUB> nanocomposite electrode make it a promising material for application in future capacitor-based energy storage systems.</P> <P><B>Highlights</B></P> <P> <UL> <LI> MWCNTs/MnO<SUB>2</SUB> nanocomposite on stainless steel mesh electrode was prepared by electrodeposition. </LI> <LI> The integrated MWCNTs/MnO<SUB>2</SUB> nanocomposite electrode delivers extraordinary electrochemical characteristics. </LI> <LI> Symmetric solid-state supercapacitor based on MWCNTs/MnO<SUB>2</SUB> nanocomposite electrode was successfully assembled. </LI> <LI> The assembled symmetric solid-state supercapacitor exhibits high energy density of 28.33 Wh/kg. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Fig. (a) shows the representative SEM image of MWCNT/MnO<SUB>2</SUB> nanocomposites with (b) the Ragone plot of the symmetric flexible solid-state supercapacitor designed in this study, in comparison with others reported in the literature.</P> <P>[DISPLAY OMISSION]</P>

고전압 구동 Li₂MnO₃-LiMO₂(M=Ni, Co, Mn)/graphite 시스템에서의 전지 수명 및 고온 방치 특성 향상에 효과적인 플루오로 화합물계 전해액에 대한 연구

유정이,신우철,이병곤,Yu, Jung-Yi,Shin, Woocheol,Lee, Byong-Gon 한국전기화학회 2013 한국전기화학회지 Vol.16 No.3

$Li_2MnO_3-LiMO_2$(M=Ni, Co, Mn) 나노 복합체는 높은 이론 용량을 가지고 있어 전기 자동차용 2차 전지 활물질 재료로 많은 연구가 진행되고 있다. 하지만 $Li_2MnO_3-LiMO_2$(M=Ni, Co, Mn)로부터 250 mAh/g 이상의 용량을 구현하기 위해서는 4.4 V 이상의 구동전압이 필요하며, 이러한 높은 구동 전압은 전지의 수명 및 고온 방치 특성의 저해 요소로 작용하고 있다. 본 연구에서는 이러한 문제점을 개선하기 위해서 FEC (Fluoroethylene carbonate), 플루오로알킬 에테르, $LiPF_6$가 주성분인 신규 전해액(F-based EL)을 설계하였다. F-based EL은 1.3 M $LiPF_6$ EC/EMC/DMC (3/4/3, v/v/v) (STD) 대비 안정한 SEI를 형성하며, 산화 안정성이 뛰어나 $Li_2MnO_3-LiMO_2$(M=Ni, Co, Mn)/graphite 셀의 수명 및 방치 중 가스 저감에 효과가 있음을 확인할 수 있었다. $Li_2MnO_3-LiMO_2$(M=Ni, Co, Mn) nano-composite is a promising cathode material for xEV application due to its high theoretic capacity. However high voltage operating system of $Li_2MnO_3-LiMO_2$(M=Ni, Co, Mn) has worked as a hurdle in its application because of the inherent demerits, such as cycle life degradation and gas evolution. In order to enhance cell performance of $Li_2MnO_3-LiMO_2$(M=Ni, Co, Mn)/graphite cell, we examined electrolyte mainly composed of FEC, fluroalkyl ether and $LiPF_6$ (F-based EL). F-based EL showed much better discharging retention ratio than 1.3 M $LiPF_6$ EC/EMC/DMC (3/4/3, v/v/v) (STD). Furthermore gas evolution, especially CO and $CO_2$ during $60^{\circ}C$ storage for 30 days was dramatically reduced owing to thermal stable SEI formation effect of F-based EL.

MnO₂ 중공 미세구의 제조에 관한 연구

문진희,박용성,Moon, Jin Hee,Park, Yong Sung 한국공업화학회 2006 공업화학 Vol.17 No.6

$MnO_{2}$는 배터리, 촉매 및 capacitor 등의 사용으로 인하여 이의 수요는 날로 증가하고 있다. 본 연구는 sacrificial core 법을 이용하여 $MnO_{2}$ 중공 미세구를 제조하였다. 이때 $MnO_{2}$ 나노입자는 manganese acetate의 가수분해 및 축합반응에 의해 제조되었다. 실험결과 물 0.2%, manganese acetate 0.65 mM, 촉매 0.02 mM를 실온에서 반응시켜 실험을 하였을 때 일정한 모양의 $MnO_{2}$ hollow microsphere를 제조할 수 있었다. Demand for $MnO_{2}$ has been increased with interest for its various applications in the fields of battery, catalyst, and capacitor. In this study, $MnO_{2}$ hollow microspheres were synthesized by sacrificial core method. $MnO_{2}$ nano particles were produced by the hydrolysis and condensation of manganese acetate. The stable $MnO_{2}$ hollow microspheres can very well be synthesized with mixing 0.2% of water, 0.65 mM of manganese acetate, and 0.02 mM catalyst at a room temperature.

0.9Pb($Mg_{1/3}Nb_{2/3}$)$O_3$-0.1Pb$TiO_3$계 완화형 강유전체에서 MnO$_2$ 첨가에 따른 압전물성의 변화

박재환,박재관,김병국,김윤호,Park, Jae-Hwan,Park, Jae-Gwan,Kim, Byung-Kook,Kim, Yoon-Ho 한국재료학회 2001 한국재료학회지 Vol.11 No.6

0.9Pb($Mg_{1/3}Nb_{2/3}$)$O_3$-0.1Pb$TiO_3$계 완화형 강유전체에서 MnO$_2$ 첨가가 압전물성에 미치는 영향을 강유전성이 우세한 온도영역인 -40~3$0^{\circ}C$의 온도범위에 걸쳐 조사하였다. MnO$_2$ 첨가에 의한 효과를 유전특성, 압전특성, 전계유기 변형특성 등의 영역에서 고찰하였다 MnO$_2$ 첨가량이 증가할수록 유전성 및 압전성은 hard piezoelectric의 경향을 나타내었다. 이러한 실험적 고찰로부터 첨가된 Mn은 강유전 도메인 분역을 고정하는 역할을 하는 것으로 제안되었다. The effects of MnO$_2$ addition on the piezoelectric properties in 0.9Pb($Mg_{1/3}Nb_{2/3}$)$O_3$-0.1Pb$TiO_3$ relaxor ferroelectrics were studied in the ferroelectricity-dominated temperature range from -4$0^{\circ}C$ to 3$0^{\circ}C$. Dielectric, piezoelectric properties and electric-field- induced strain were examined to clarify the effect of MnO$_2$ addition. As the added amount of MnO$_2$ increase. dielectric and piezoelectric properties of Pb(Mg$_{1/3}$ Nb$_{2/3}$O$_3$ became harder. From the experimental results, it was suggested that Mn behaves as a ferroelectric domain pinning element.

Hierarchical coating of MnO₂ nanosheets on ZnCo₂O₄ nanoflakes for enhanced electrochemical performance of asymmetric supercapacitors

Kumbhar, Vijay S.,Kim, Do-Heyoung Elsevier 2018 ELECTROCHIMICA ACTA Vol.271 No.-

<P><B>Abstract</B></P> <P>The design of heterostructured pseudo-capacitive materials plays a key role in fabricating asymmetric supercapacitors (ASCs) with high energy density and electrochemical cycle life for the evolution of next-generation energy storage devices. Use of ZnCo<SUB>2</SUB>O<SUB>4</SUB> nanoflakes covered with MnO<SUB>2</SUB> nanosheets led to a synergistic effect that produced a larger electroactive surface area for charge storage than that provided by bare ZnCo<SUB>2</SUB>O<SUB>4</SUB> nanoflakes or MnO<SUB>2</SUB> nanosheets. The ZnCo<SUB>2</SUB>O<SUB>4</SUB> nanoflakes served as the backbone for the growth of the MnO<SUB>2</SUB> nanosheets. The ZnCo<SUB>2</SUB>O<SUB>4</SUB>-MnO<SUB>2</SUB> heterostructure was synthesized on Ni foam using a combined binder-free electrodeposition and hydrothermal method. The electrode formed using this unique method showed a maximum specific capacitance of 2057 F g<SUP>−1</SUP> at a current density of 1 A g<SUP>−1</SUP> with a rate capability of 65% even after a 15-fold increase in current density. Moreover, the electrode showed a cycling stability of 96.5% after 5000 successive cycles at a current density of 15 A g<SUP>−1</SUP>. An ASC formed using ZnCo<SUB>2</SUB>O<SUB>4</SUB>-MnO<SUB>2</SUB> as the positive electrode and activated carbon as the negative electrode delivered a maximum energy density of 69 W h kg<SUP>-1</SUP> with 93.5% capacity retention after 5000 cycles. Further, an experiment to investigate the commercial application of ASCs was conducted.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A MnO<SUB>2</SUB> nanosheets were coated on ZnCo<SUB>2</SUB>O<SUB>4</SUB> nanoflakes using a simple, eco-friendly, and low cost chemical methods. </LI> <LI> The ZnCo<SUB>2</SUB>O<SUB>4</SUB>-MnO<SUB>2</SUB> heterostructure exhibited a specific capacitance of 2057 F g<SUP>-1</SUP>. </LI> <LI> The ZnCo<SUB>2</SUB>O<SUB>4</SUB>-MnO<SUB>2</SUB> heterostructure exhibited a cycling stability of 96.5% after 5000 cycles. </LI> <LI> As-fabricated ZnCo<SUB>2</SUB>O<SUB>4</SUB>//activated carbon asymmetric supercapacitor (ASC) exhibited an energy density of 69 W h kg<SUP>-1</SUP>. </LI> <LI> Finally the demonstration of the as-prepared ASC confirmed the practical feasibility of the device. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>