Secondary Battery Applications Research Articles

Electrochemical synthesis and In situ spectroelectrochemistry of conducting NMPy‐TiO2 and ZnO polymer nanocomposites for Li secondary battery applications

ABSTRACTPoly(N‐methylpyrrole) (PNMPy), poly(N‐methylpyrrole‐TiO2) (PNMPy‐TiO2), and poly (N‐methylpyrrole‐ZnO) (PNMPy‐ZnO) nanocomposites were synthesized by in situ electropolymerization for cathode active material of lithium secondary batteries. The charge–discharging behavior of a Li/LiClO4/PNMPy battery was studied and compared with Li/LiClO4/PNMPy‐nanocomposite batteries. The nanocomposites and PNMPy films were characterized by cyclic voltammetry, in situ resistivity measurements, in situ UV–visible, and Fourier transform infra‐red (FTIR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The differences between redox couples (ΔE) were obtained for polymer nanocomposites and PNMPy films. During redox scan, a negative shift of potential was observed for polymer nanocomposite films. Significant differences from in situ resistivity of nanocomposites and PNMPy films were obtained. The in situ UV–visible spectra for PNMPy and polymer nanocomposite films show the intermediate spectroscopic behavior between polymer nanocomposites and PNMPy films. The FTIR peaks of polymer nanocomposite films were found to shift to higher wavelengths in PNMPy films. The SEM and TEM micrographs of nanocomposite films show the presence of nanoparticle in PNMPy backbone clearly. The result suggests that the inorganic semiconductor particles were incorporated in organic conducting PNMPy, which consequently modifies the properties and morphology of the film significantly. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41526.

Electrochemistry of magnesium electrolytes in ionic liquids for secondary batteries.

The electrochemistry of Mg salts in room-temperature ionic liquids (ILs) was studied using plating/stripping voltammetry to assess the viability of IL solvents for applications in secondary Mg batteries. Borohydride (BH4(-)), trifluoromethanesulfonate (TfO(-)), and bis(trifluoromethanesulfonyl)imide (Tf2N(-)) salts of Mg were investigated. Three ILs were considered: l-n-butyl-3-methylimidazolium (BMIM)-Tf2N, N-methyl-N-propylpiperidinium (PP13)-Tf2N, and N,N-diethyl-N-methyl(2-methoxyethyl)ammonium (DEME(+)) tetrafluoroborate (BF4(-)). Salts and ILs were combined to produce binary solutions in which the anions were structurally similar or identical, if possible. Contrary to some prior reports, no salt/IL combination appeared to facilitate reversible Mg plating. In solutions containing BMIM(+), oxidative activity near 0.8 V vs Mg/Mg(2+) is likely associated with the BMIM cation, rather than Mg stripping. The absence of voltammetric signatures of Mg plating from ILs with Tf2N(-) and BF4(-) suggests that strong Mg/anion Coulombic attraction inhibits electrodeposition. Cosolvent additions to Mg(Tf2N)2/PP13-Tf2N were explored but did not result in enhanced plating/stripping activity. The results highlight the need for IL solvents or cosolvent systems that promote Mg(2+) dissociation.

Effect of the length and surface area on electrochemical performance of cobalt oxide nanowires for alkaline secondary battery application

One-dimensional porous Co3O4 nanowires with different length have been successfully synthesized by thermal decomposition of Co-NA polymer precursors at various hydrothermal reaction times. The positive effects of longer nanowires and larger surface area on electrochemical performance of Co3O4 samples were investigated systematically. All the as-prepared Co3O4 samples display excellent discharge capacities and cycle stability on account of large surface area and porous structure, indicating great potential application of porous Co3O4 nanowires for alkaline rechargeable batteries. The Co3O4-24 h sample with the longest length shows the most outstanding electrochemical performance, and displays the maximum discharge capacity of 450.1 mAh g−1 with the capacity retention of 90.4% after 100 cycles at a current density of 100 mA g−1. Electrochemical reactions between Co and Co(OH)2 occurring on the Co3O4 electrodes are investigated by XRD, cyclic voltammetry (CV) and charge–discharge measurements.

LiCoPO4 and Li2CoSiO4 Nanoparticles Synthesis by Supercritical Fluid Process for Lithium Ion Battery Application

In recent years, transition metal polyanionic compounds such as phosphates and silicates are considered as promising positive electrode materials for lithium-ion batteries. These members of the lithium metal polyanion family have been a major focus of research for reasons of high safety, low cost and low environmental impact. Among, metal phosphate cathode material, LiCoPO4 electrode materials have received considerable attention for the application in lithium secondary batteries due to its high stability, non toxicity, good charge/discharge capabilities and cheap cost. Recently, polyanion-containing frameworks are of great research interest in the area of lithium ion batteries, because, these materials can reversibly insert/extract two lithium ions per formula unit would help to increase the capacity and energy density. Regarding this, silicates with the general formula Li2MSiO4 (M=Mn, Fe and Co) have been considered as potential lithium insertion/ extraction cathodes. Among silicates, Li2CoSiO4 is an attractive cathode due to its high operating voltage. In this work, we have used supercritical fluid process for the synthesis of LiCoPO4 and Li2CoSiO4 nanoparticles and are investigated for lithium ion battery applications. LiCoPO4 and Li2CoSiO4 nanoparticles were synthesized from LiOH.H2O/Lithum acetyl acetonate, CoCl3.6H2O/C4H6CoO4.4H2O and H3PO4/TEOS in molar ratio of 1:1:1 for LiCoPO4 and 4:1:1 for Li2CoSiO4 nanoparticles via supercritical fluid process. Cheap solvents such as water, ethanol and water-ethanol mixed solvents were used to prepare precursor solutions and reducing agents were also used in the synthesis. Supercritical synthesis was carried out at 400-450oC for about 5-10 min of reaction time. Then, the products were washed thoroughly in water and ethanol followed by vacuum dry for overnight. The as-synthesized LiCoPO4 and Li2CoSiO4 nanoparticles showed 20-150 nm in diameter, which was analysed by transmission electron microscopy (TEM). Further, LiCoPO4 and Li2CoSiO4 nanoparticles were systematically characterized using powder X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM), energy dispersive spectroscopy (EDS) and charge-discharge measurements. The discharge capacities of 80-110 mAhg-1 for LiCoPO4 nanoparticles and 40-110 mAhg-1 for Li2CoSiO4 nanoparticles were observed. The electrochemical property was measured by galvanostatic discharge method using 1M LiPF6 mixed in EC:DEC as electrolyte. The electrode was prepared using 10 wt% PTFE as binder. The weight ratio of active material:AB:PTFE are 80:10:10.

Keynote Presentation: Nanoporous Hybrid Materials - Transport Phenomena and Applications in Secondary Lithium Metal Batteries

not Available.

Properties of sodium-based ionic liquid electrolytes for sodium secondary battery applications

Abstract The enormous demands on available global lithium resources have raised concerns about the sustainability of the supply of lithium. Sodium secondary batteries have emerged as promising alternatives to lithium batteries. We describe here sodium bis(trifluoromethylsulfonyl) amide (NaNTf 2 ) electrolyte systems based on 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl) amide (C 4 mpyrNTf 2 ) ionic liquids. The electrochemical stability of the system was examined; a pair of facile cathodic and anodic processes around 0 V vs. Na/Na + were observed in cyclic voltammetry measurements and interpreted as deposition and dissolution of sodium metal. Density, viscosity and conductivity of the electrolytes were studied. It was found that the ionic conductivity of electrolytes reached as high as 8 mS/cm, decreasing slowly as the salt content increased due to increasing of viscosity and density of the electrolyte. Therefore, sodium electrolytes based on C 4 mpyrNTf 2 appear to be promising for secondary sodium battery applications.

Stable and Efficient Li-Ion Battery Anodes Prepared from Polymer-Derived Silicon Oxycarbide–Carbon Nanotube Shell/Core Composites

We demonstrate the synthesis and electrochemical performance of polymer-derived silicon oxycarbide–carbon nanotube (SiOC–CNT) composites as a stable lithium intercalation material for secondary battery applications. Composite synthesis was achieved through controlled thermal decomposition of 1,3,5,7-tetramethyl 1,3,5,7-tetravinyl cyclotetrasiloxane (TTCS) precursor on carbon nanotubes surfaces that resulted in formation of shell/core type ceramic SiOC–CNT architecture. Li-ion battery anode (prepared at a loading of ∼1.0 mg cm–2) showed stable charge capacity of 686 mA h g–1 even after 40 cycles. The average Coulombic efficiency (excluding the first cycle loss) was 99.6%. Further, the post electrochemical imaging of the dissembled cells showed no apparent damage to the anode surface, highlighting improved chemical and mechanical stability of these composites. A similar trend was observed in the rate capability tests, where the SiOC–CNT anode (with 5 wt % loading in TTCS) again showed stable performance, co...

Jung-Ki Park: Principles and applications of lithium secondary batteries

Jung-Ki Park: Principles and applications of lithium secondary batteries

Electrochemical properties of semi-interpenetrating polymer network solid polymer electrolytes based on multi-armed oligo(ethyleneoxy) phosphate

In this work we synthesize a series of plasticizers and a crosslinker based on a multi-armed oligo(ethyleneoxy) phosphate and carry out in-situ radical polymerization of the precursor solution containing the plasticizers and crosslinker to produce semi-interpenetrating polymer network (semi-IPN) solid polymer electrolytes (SPEs). A high-quality free-standing film is obtained with a tensile strength as high as 1.2 MPa. Several factors are investigated to optimize the ionic conductivity of the solid polymer electrolytes such as the length of ethylene oxide units in the plasticizers, the concentration of lithium salts, the content of the plasticizers, and the different types of lithium salts. The maximum ionic conductivity of the SPEs is found to reach 5.0 × 10−4 S cm−1 at 30 °C, together with the wide electrochemical stability window of above 5.0 V and the columbic efficiency more than 70% in reversible lithium plating–stripping cycles, making phosphate-based semi-IPN SPEs a promising candidate for application in solid-state lithium secondary batteries.

Conformal N-doped carbon on nanoporous TiO2 spheres as a high-performance anode material for lithium-ion batteries

Conformal N-doped carbon (NC) on nanoporous TiO2 spheres has been successfully synthesized via a facile solution-phase process and subsequent heat treatment. The highly conductive and uniform NC layer coated on the surface of nanoporous TiO2 spheres facilitates lithium ion diffusion and electronic transport. The resulting TiO2@NC nanohybrid not only delivers a high capacity of ∼170 mA h g−1 at a current density of 0.1 A g−1, but also exhibits excellent rate capability (∼102 mA h g−1 at a current density of 2.0 A g−1). The as-formed porous TiO2@NC electrode is promising for secondary battery applications with high power and energy densities.

Self-assembled synthesis of monodispersed mesoporous Li4Ti5O12 beads and their applications in secondary lithium-ion batteries

Monodispersed mesoporous lithium titanate was synthesized by combining sol–gel and solvothermal process. The role of solvothermally treating amorphous TiO2 precursors could produce mesoporous anatase beads with the incorporation of Li2O. Calcination helps the diffusion between TiO2 and Li2O, leading to mesoporous lithium titanate. The crystalline structure and morphological observation of the as-synthesized mesoporous Li4Ti5O12 were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The mesoporous structure could be directly observed through the N2 adsorption/desorption isotherm. It was demonstrated that the electrochemical performance was significantly improved by the mesoporous structure. The mesoporous lithium titanate exhibited a stable capacity of 160mAhg−1 at 0.5C. Besides, the reversible capacity at 5C remained over half of that at 0.5C. The superior C-rate performance should be associated with the mesoporous structure, facilitating lithium transportation ability during cycling.

Olivine type LiMn1/3Co1/3Ni1/3PO4 Cathode for Secondary Battery Applications

not Available.

Indigo carmine (IC) doped polypyrrole (PPy) as a free-standing polymer electrode for lithium secondary battery application

Flexible free-standing polypyrrole-indigo carmine (PPy-IC) films were designed as additive-free anode material for lithium secondary batteries and were produced via the electropolymerization method. The films are soft, lightweight, mechanically robust, and electrically conductive. The films display a cauliflower-like structure consisting of micron-scale spherical grains, which are related to dopant intercalation in the polymeric chains. The morphologies and electrochemical behaviour of the free-standing PPy-IC films were affected by the electropolymerization conditions. Electrochemical tests demonstrated that the discharge capacity and initial coulombic efficiency increased as the thickness of the films decreased. The PPy-IC films prepared at lower deposition time (30min) and lower deposition current density (0.4mAcm−2) exhibited higher discharge capacity (83mAhg−1 beyond 100cycles) in the voltage range of 0.01–3.0V. These free-standing films can be used as possible anode materials to satisfy the new market demand for flexible/bendable lithium polymer or polymer batteries that are suitable for roll-up displays, wearable devices, and implanted medical devices used in biological and biomedical systems.

Silver Vanadium Phosphorous Oxide, Ag0.48VOPO4: Exploration as a Cathode Material in Primary and Secondary Battery Applications

Silver vanadium phosphorous oxides (SVPO) have been recently shown to be a promising new class of materials for primary lithium batteries with the synthesis and electrochemical investigation of Ag2VO2PO4. More recently a second silver vanadium phosphorous oxide, Ag0.48VOPO4·1.9H2O, was reported. The investigation reported here provides mechanistic information regarding the reduction mechanism of Ag0.48VOPO4·1.9H2O via magnetic susceptibility measurements, quantitative XRD, and the use of galvanostatic intermittent titration (GITT) type tests. Ag0.48VOPO4·1.9H2O shows promise as a cathode material for primary cell applications demanding high voltage, state of charge indication, and good pulse performance such as biomedical battery applications. Additionally, the first exploration of electrochemical reversibility of a silver vanadium phosphorous oxide material is reported. Via slow scan voltammetry and ex-situ XRD of both discharged and charged material, Ag0.48VOPO4•1.9H2O shows reversibility of the vanadium center however, little reincorporation of the silver metal produced during the discharge is observed during the charge step.

Nano SIMS characterization of boron- and aluminum-coated LiNi1/3Co1/3Mn1/3O2 cathode materials for lithium secondary ion batteries

The LiNi1/3Co1/3Mn1/3O2 powders required for the present study, obtained by coprecipitation method has been surface coated with boron and aluminum. The morphology and crystal structure of powders have been characterized using scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy techniques. The elemental distribution of the coated samples analyzed by transmission electron microscopy images and nano secondary ion mass spectrometry indicates a thin uniform layer of [B, Al]2O3 on the surface of spherical LiNi1/3Co1/3Mn1/3O2. The surface-modified LiNi1/3Co1/3Mn1/3O2 has been explored as a cathode material for lithium secondary ion battery applications. The electrochemical charge–discharge results reveal that the capacity retention rate of coated LiNi1/3Co1/3Mn1/3O2 after 40 cycles at 1 C rate maintains 93% of the initial discharge capacity while the rate of bare LiNi1/3Co1/3Mn1/3O2 maintains only 88%. It is noticed that the small amounts of boron and aluminum coatings on the surface of LiNi1/3Co1/3Mn1/3O2 can significantly improve the electrochemical properties of electrode materials because of the suppression of reaction between the cathode and the electrolytes.

Continuous supercritical hydrothermal synthesis: lithium secondary ion battery applications

Nanosized lithium iron phosphate (LiFePO4) and transition metal oxide (MO, where M is Cu, Ni, Mn, Co, and Fe) particles are synthesized continuously in supercritical water at 25–30 MPa and 400°C under various conditions for active material application in lithium secondary ion batteries. The properties of the nanoparticles, including crystallinity, particle size, surface area, and electrochemical performance, are characterized in detail. The discharge capacity of LiFePO4 was enhanced up to 140 mAh/g using a simple carbon coating method. The LiFePO4 particles prepared using supercritical hydrothermal synthesis (SHS) deliver the reversible and stable capacity at a current density of 0.1 C rate during ten cycles. The initial discharge capacity of the MO is in the range of 800–1,100 mAh/g, values much higher than that of graphite. However, rapid capacity fading is observed after the first few cycles. The continuous SHS can be a promising method to produce nanosized cathode and anode materials.

Multi-electron reaction materials for high energy density batteries

The need for high energy density batteries becomes increasingly important for the development of new and clean energy technologies, such as electric vehicles and electrical storage from wind and solar power. The search for new energetic materials of primary and secondary batteries with higher energy density has been highlighted in recent years. This review surveys recent advances in the research field of high energy density electrode materials with focus on multi-electron reaction chemistry of light-weight elements and compounds. In the first section, we briefly introduce the basic strategies for enhancement of the energy density of primary batteries based on multi-electron reactions. The following sections present overviews of typical electrode materials with multi-electron chemistry and their secondary battery applications in aqueous and non-aqueous electrolytes. Finally, the challenges and ongoing research strategies of these novel electrode materials and battery systems for high density energy storage and conversion are discussed.

Synthesis and Electrochemistry of Silver Hollandite

The electrochemical study of silver hollandite is presented, establishing the promise of this material for future secondary battery applications. A low temperature reflux-based strategy for the synthesis of pure silver hollandite is described, where an enhancement in silver loading was achieved relative to other low temperature methods.

Battery performance of PMMA-grafted PE separators prepared by pre-irradiation grafting technique

Poly(methyl methacrylate)-grafted polyethylene (PE-g-PMMA) separators were prepared by pre-irradiation grafting technique of methyl methacrylate onto a commercial polyethylene separator. The prepared separators were characterized by using charge/discharge (C/D) cycling test, AC impedance, and thermal stability analyses. Thermal shrinkage (TS) of the PE-g-PMMA separators decreased with an increasing degree of grafting up to 70% above which it was saturated. The PE-g-PMMA separators showed a better oxidation stability on the anode up to 5 V and a better cycle life performance than the original PE separator. These characteristics make the prepared separators suitable for applications in high voltage secondary lithium batteries.

Effect of thermal history and characterization of plasticized, composite polymer electrolyte based on PEO and tetrapropylammonium iodide salt (Pr 4N +I -)

The search for anionic conductors based on solid polymer electrolytes is important for the development of photo-electrochemical (PEC) solar cells due to their many favourable chemical and physical properties. Although solid polymer electrolytes have been extensively studied as cation, mainly lithium ion, conductors for applications in secondary batteries, their use as anionic conductors have not been studied in greater detail. In a previous paper we reported the application of a PEO based iodide ion conducting electrolyte in a PEC solar cell. This electrolyte had the composition PEO: Pr 4N +I − = 9:1 with 50 wt.% ethylene carbonate (EC). In this work we have studied the effect of incorporating alumina filler on the properties of this electrolyte. The investigation was extended to electrical and dielectric measurements including high frequency impedance spectroscopy and thermal analysis. In the DSC themograms two endothermic peaks have been observed on heating, one of these peaks is attributed with the melting of the PEO crystallites, while the other peak with a melting temperature ~ 30 °C is attributed to the melting of the EC rich phase. The melting temperature of both these peaks shows a marked variation with alumina content in the electrolyte. The temperature dependence of the conductivity shows that there is an abrupt conductivity increase in the first heating run evidently due to the melting of the EC rich phase. High conductivity values are retained at lower temperatures in the second heating. Conductivity isotherms show the existence of two maxima, one at ~ 5% Al 2O 3 content and the other at ~ 15%. The occurrence of these two maxima has been explained in terms of the interactions caused by alumina grains, the crystallinity and melting of the PEO rich phase. As seen from latent heat of melting, the crystallinity of the electrolyte has reduced considerably during the first heating run. In contrast to the conductivity enhancement caused by ceramic fillers in PEO-based cation containing electrolytes, no conductivity enhancement has been observed in the present PEO based anionic conducting materials by adding alumina except at low temperatures.