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Alfaruqi, Muhammad H.,Mathew, Vinod,Song, Jinju,Kim, Sungjin,Islam, Saiful,Pham, Duong Tung,Jo, Jeonggeun,Kim, Seokhun,Baboo, Joseph Paul,Xiu, Zhiliang,Lee, Kug-Seung,Sun, Yang-Kook,Kim, Jaekook American Chemical Society 2017 Chemistry of materials Vol.29 No.4
<P>Rechargeable zinc-ion batteries (ZIBs) with high energy densities appear promising to meet the increasing demand for safe and sustainable energy storage devices. 1.5 However, electrode research on this low-cost and green system are faced with stiff challenges of identifying materials that permit divalent ion-intercalation/deintercalation. Herein, we present layered-type LiV3O8 (LVO) as a prospective intercalation cathode for zinc-ion batteries (ZIBs) with high storage capacities. The detailed phase evolution study during Zn intercalation using electrochemistry, in situ XRD, and simulation techniques reveals the large presence of a single-phase domain that proceeds via a stoichiometric ZnLiV3O8 phase to reversible solid-solution ZnyLiV3O8 (y > 1) phase. The unique behavior, which is different from the reaction with lithium, contributes to high specific capacities of 172 mAh g(-1) and amounts to 75% retention of the maximum capacity achieved in 65 cycles with 100% Coulombic efficiency at a current density of 133 mA g(-1). The remarkable performance makes the development of this low-cost and safe battery technology very promising, and this study also offers opportunities to enhance the understanding on electrochemically induced metastable phases for energy storage applications.</P>
Alfaruqi, Muhammad Hilmy,Gim, Jihyeon,Kim, Sungjin,Song, Jinju,Jo, Jeonggeun,Kim, Seokhun,Mathew, Vinod,Kim, Jaekook Elsevier 2015 Journal of Power Sources Vol.288 No.-
<P><B>Abstract</B></P> <P>In the present study, a nanorod-type α-MnO<SUB>2</SUB> cathode is prepared by a facile hydrothermal method for rechargeable aqueous zinc-ion battery (ZIB) applications. Electron microscopy studies reveal rod shaped particles with approximately 20 nm of width and 200 nm of length. When tested for aqueous ZIBs, the α-MnO<SUB>2</SUB> nanorod cathode exhibits an initial discharge capacity of 233 mA h/g at a current density of 83 mA/g with nearly 100% Coulombic efficiencies under prolonged cycling. Besides, the prepared cathode demonstrates decent rate capabilities at higher current densities (43.33 and 31.48 mA h/g at 1333 and 1666 mA/g, respectively). Ex-situ synchrotron XAS investigations clearly establish the reversibility of electrochemical Zn-insertion into the α-MnO<SUB>2</SUB> nanorod cathode. The analyses also reveal that the host α-MnO<SUB>2</SUB> structure demonstrates considerable structural stability during Zn-insertion/extraction. Further, a combination of ex-situ synchrotron XRD studies, visualization and pattern-fitting software programs not only confirm electrochemical Zn-insertion into the host α-MnO<SUB>2</SUB> structure but also suggest that the unit cell volume of the [2×2] tunnels in the α-MnO<SUB>2</SUB> host expands by approximately 3.12% during Zn-insertion. The present study thus paves the way for further development of eco-friendly ZIB as an ideal energy storage system due to its excellent safety and reliability.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An α-MnO<SUB>2</SUB> nanorod cathode demonstrated enhanced electrochemical properties versus zinc. </LI> <LI> Synchrotron XAFS and XRD analyses confirm reversible Zn-insertion in α-MnO<SUB>2</SUB>. </LI> <LI> The combined analysis reveals structural stability in α-MnO<SUB>2</SUB> after Zn-insertion. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Alfaruqi, M.H.,Islam, S.,Gim, J.,Song, J.,Kim, S.,Pham, D.T.,Jo, J.,Xiu, Z.,Mathew, V.,Kim, J. North Holland 2016 Chemical physics letters Vol.650 No.-
<P>Tunnel-type alpha-MnO2 with a nanorod morphology was prepared via a simple solvent-free synthesis method for use in aqueous zinc-ion battery (ZIB). This synthesis method produced alpha-MnO2 with a high BET surface area of 153 m(2)g(-1).alpha-MnO2 electrode demonstrated remarkable zinc storage properties (first and second discharge capacities of 323 and 270 mAh g(-1) at 16 mA g(-1)) with good capacity retentions and rate capability. After charging within only 60 s, the alpha-MnO2 nanorod cathode delivered a considerable discharge capacity of 115 mAh g(-1) when cycled at current density of 16 mA g(-1). (C) 2016 Elsevier B.V. All rights reserved.</P>
Alfaruqi, M.H.,Islam, S.,Song, J.,Kim, S.,Pham, D.T.,Jo, J.,Kim, S.,Baboo, J.P.,Putro, D.Y.,Mathew, V.,Kim, J. North Holland 2017 Chemical physics letters Vol.681 No.-
<P>Rhombohedral Li2NaV2(PO4)(3) is very attractive cathode material for lithium-ion battery (LIB) application due to its single voltage plateau at 3.7 V that provides a constant output power. Here, for the first time, we report a direct and simple synthesis of high performance carbon-coated rhombohedral Li2NaV2(PO4)(3) (LNVP/C) nanoflake cathode using a pyro-synthesis technique. The cathode demonstrates long cycle stability (100% capacity retention over 300 cycles) and high rate capabilities (77 and 55 mAh g(-1) at 6.4 and 12C, respectively). The present study may facilitate a simple and low-cost preparation technique towards high performance cathode materials for advanced LIB applications. (C) 2017 Elsevier B.V. All rights reserved.</P>
Alfaruqi, Muhammad H.,Mathew, Vinod,Gim, Jihyeon,Kim, Sungjin,Song, Jinju,Baboo, Joseph P.,Choi, Sun H.,Kim, Jaekook American Chemical Society 2015 Chemistry of materials Vol.27 No.10
<P>In the present study, an in-depth investigation on the structural transformation in a mesoporous gamma-MnO2 cathode during electrochemical reaction in a zinc-ion battery (ZIB) has been undertaken. A combination of in situ Synchrotron XANES and XRD studies reveal that the tunnel-type parent gamma-MnO2 undergoes a structural transformation to spinel-type Mn(III) phase (ZnMn2O4) and two new intermediary Mn(II) phases, namely, tunnel-type gamma-ZnxMnO2 and layered-type L-ZnyMnO2, and that these phases with multioxidation states coexist after complete electrochemical Zn-insertion. On successive Zn-deinsertion/extraction, a majority of these phases with multioxidation states is observed to revert back to the parent gamma-MnO2 phase. The mesoporous gamma-MnO2 cathode, prepared by a simple ambient temperature strategy followed by low-temperature annealing at 200 degrees C, delivers an initial discharge capacity of 285 mAh g(-1) at 0.05 mA cm(-2) with a defined plateau at around 1.25 V vs Zn/Zn2+. Ex situ HR-TEM studies of the discharged electrode aided to identify the lattice fringe widths corresponding to the Mn(III) and Mn(II) phases, and the stoichiometric composition estimated by ICP analysis appears to be concordant with the in situ findings. Ex situ XRD studies also confirmed that the same electrochemical reaction occurred on repeated discharge/charge cycling. Moreover, the present synthetic strategy offers solutions for developing cost-effective and environmentally safe nanostructured porous electrodes for cheap and eco-friendly batteries.</P>
Alfaruqi, Muhammad Hilmy,Islam, Saiful,Mathew, Vinod,Song, Jinju,Kim, Sungjin,Tung, Duong Pham,Jo, Jeonggeun,Kim, Seokhun,Baboo, Joseph Paul,Xiu, Zhiliang,Kim, Jaekook Elsevier 2017 APPLIED SURFACE SCIENCE - Vol.404 No.-
<P><B>Abstract</B></P> <P>In this work, we demonstrate the first use of a V-doped MnO<SUB>2</SUB> nanoparticle electrode for zinc-ion battery (ZIB) applications. The V-doped MnO<SUB>2</SUB> was prepared via a simple redox reaction and the X-ray diffraction studies confirmed the formation of pure MnO<SUB>2</SUB>, accompanied by an anisotropic expansion of MnO<SUB>2</SUB> lattice, suggesting the incorporation of V-ions into the MnO<SUB>2</SUB> framework. V doping of MnO<SUB>2</SUB> not only increased the specific surface area but also improved the electronic conductivity. When Zn-storage properties were tested, the V-doped MnO<SUB>2</SUB> electrode registered a higher discharge capacity of 266mAhg<SUP>−1</SUP> compared to 213mAhg<SUP>−1</SUP> for the pure MnO<SUB>2</SUB> electrode. On prolonged cycling, the doped electrode retained 31% higher capacity than that of the bare MnO<SUB>2</SUB> electrode and thereby demonstrated superior cycling performance. This study may pave the way towards understanding the enhancement of the energy storage properties via doping in electrodes of aqueous ZIB applications and also furthers the efforts for the practical realization of a potential eco-friendly battery system.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The V-doped MnO<SUB>2</SUB> was prepared by a simple ambient redox reaction. </LI> <LI> The V-doped MnO<SUB>2</SUB> was tested as a cathode in aqueous zinc-ion batteries (ZIBs). </LI> <LI> The doped cathode showed better zinc-storage properties than the bare cathode. </LI> <LI> The present study facilitates the development of safe and reliable aqueous ZIBs. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Alfaruqi, Muhammad Hilmy,Islam, Saiful,Putro, Dimas Yunianto,Mathew, Vinod,Kim, Sungjin,Jo, Jeonggeun,Kim, Seokhun,Sun, Yang-Kook,Kim, Kwangho,Kim, Jaekook Elsevier 2018 ELECTROCHIMICA ACTA Vol.276 No.-
<P><B>Abstract</B></P> <P>Layered MnO<SUB>2</SUB> is very attractive cathode material for zinc-ion battery (ZIB) due to its large interlayer distance, high discharge capacity, low cost, and environmental benignity. However, layered MnO<SUB>2</SUB> exhibits capacity fading. Therefore, detailed studies of the structural transformation and electrochemical mechanism of layered MnO<SUB>2</SUB> during cycling are urgently required for performance improvement. In this contribution, we have utilized <I>in situ</I> synchrotron, <I>ex situ</I> X-ray diffraction, and <I>ex situ</I> synchrotron X-ray absorption spectroscopy analyses in order to evaluate the structural transformation of a layered MnO<SUB>2</SUB> during Zn-ion insertion. We found that during initial cycles, the electrode was able to maintain its layered structure; however, after prolonged cycles, it completely transformed into an irreversible spinel structure. We also observed the manganese dissolution from the electrode into the electrolyte during continuous cycling. The formation of irreversible spinel phase and manganese dissolution are responsible for capacity fading. Our findings provide the understanding for further improvement of layered MnO<SUB>2</SUB> as cathode material for next generation ZIB systems.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Structural transformation of layered MnO<SUB>2</SUB> during Zn-ion insertion is investigated. </LI> <LI> During initial cycles, layered MnO<SUB>2</SUB> electrode is able to maintain its structure. </LI> <LI> Layered MnO<SUB>2</SUB> electrode transforms into spinel structure after prolonged cycles. </LI> <LI> Spinel formation and manganese dissolution are responsible for capacity loss. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Islam, Saiful,Alfaruqi, Muhammad Hilmy,Putro, Dimas Yunianto,Mathew, Vinod,Kim, Sungjin,Jo, Jeonggeun,Kim, Seokhun,Sun, Yang-Kook,Kim, Kwangho,Kim, Jaekook Wiley (John WileySons) 2018 ChemSusChem Vol.11 No.13
<P>Rechargeable hybrid aqueous batteries (ReHABs) have emerged as promising sustainable energy-storage devices because all components are environmentally benign and abundant. In this study, a carbon-wrapped sponge-like Na3V2(PO4)(3) nanoparticle (NVP@C) cathode is prepared by a simple pyrosynthesis for use in the ReHAB system with impressive rate capability and high cyclability. A high-resolution X-ray diffraction study confirmed the formation of pure Na ion superionic conductor (NASICON) NVP with rhombohedral structure. When tested in the ReHAB system, the NVP@C demonstrated high rate capability (66mAhg(-1) at 32C) and remarkable cyclability over 1000 cycles (about 72% of the initial capacity is retained at 30C). Structural transformation and oxidation change studies of the electrode evaluated by using insitu synchrotron X-ray diffraction and exsitu X-ray photoelectron spectroscopy, respectively, confirmed the high reversibility of the NVP@C electrode in the ReHAB system through a two-phase reaction. The combined strategy of nanosizing and carbon-wrapping in the NVP particles is responsible for the remarkable electrochemical properties. The pyrosynthesis technique appears to be a promising and feasible approach to prepare a high-performance electrode for safe and low-cost ReHAB systems as nextgeneration large-scale energy storage devices.</P>
Xiu, Zhiliang,Alfaruqi, Muhammad Hilmy,Gim, Jihyeon,Song, Jinju,Kim, Sungjin,Thi, Trang Vu,Duong, Pham Tung,Baboo, Joseph Paul,Mathew, Vinod,Kim, Jaekook The Royal Society of Chemistry 2015 Chemical communications Vol.51 No.61
<P>Hierarchical meso-/macroporous anatase TiO2 was synthesized by the hydrolysis of a titanium metal-organic framework precursor followed by calcination in air. This unique porous feature enables the superior rate capability and excellent cycling stability of anatase TiO2 as an anode for rechargeable lithium-ion batteries.</P>
Islam, Saiful,Alfaruqi, Muhammad Hilmy,Song, Jinju,Kim, Sungjin,Pham, Duong Tung,Jo, Jeonggeun,Kim, Seokhun,Mathew, Vinod,Baboo, Joseph Paul,Xiu, Zhiliang,Kim, Jaekook Elsevier Inc 2017 Journal of Energy Chemistry Vol.26 No.4
<P>In this study, we report the cost-effective and simple synthesis of carbon-coated alpha-MnO2 nanoparticles (alpha-MnO2@C) for use as cathodes of aqueous zinc-ion batteries (ZIBs) for the first time. alpha-MnO2@C was prepared via a gel formation, using maleic acid (C4H4O4) as the carbon source, followed by annealing at low temperature of 270 degrees C. A uniform carbon network among the alpha-MnO2 nanoparticles was observed by transmission electron microscopy. When tested in a zinc cell, the alpha-MnO2@C exhibited a high initial discharge capacity of 272 mAh/g under 66 mA/g current density compared to 213 mAh/g, at the same current density, displayed by the pristine sample. Further, alpha-MnO2@C demonstrated superior cycleability compared to the pristine samples. This study may pave the way for the utilizing carbon-coated MnO2 electrodes for aqueous ZIB applications and thereby contribute to realizing high performance eco-friendly batteries. (C) 2017 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.</P>