Li3VO4/C composites have been synthesized by a sol-gel method and post-annealing at 650 °C for 1 h in N2 flow using either tartaric acid, malic acid, or glucose as both chelating agents and carbon source. The presence of these organic additives crucially affects morphology and crystallite size of the final product. It is found that the electrochemical properties of Li3VO4/C as anode material for Li-ion batteries (LIBs) are influenced by the morphology, texture and carbon content of the material. When using carboxylic acids as carbon source composites with mesoporous structure and a high surface area are obtained that display an enhanced electrochemical activity. Initially, reversible capacity of about 400 mAh g-1 is obtained. In contrast, Li3VO4/C synthesized with glucose outperforms in terms of cycling stability. It exhibits a discharge capacity of 299 mAh g-1 after 100 cycles corresponding to an excellent capacity retention of 96 %. The favorable effect of carbon composites on the electrochemical performance of Li3VO4 is shown.
MoO2/C-composites have been fabricated for the first time by a tartaric acid/glucose-assisted sol-gel method with post-annealing at 500 °C for 1 h in N2 flow. The synthesized materials were fully characterized with respect to structure, morphology, and electrochemical properties. Compared with tartaric acid-assisted products, the adoption of glucose as carbon source effectively increases the carbon content in the composites. Irrespective of the organic component, the composites exhibit low crystallinity and small grain size. This results in good electrochemical performance of the anode materia…
Effective passivation of lithium metal surfaces, and prevention of battery-shorting lithium dendrite growth, are critical for implementing lithium-metal-anodes for batteries with increased power densities. Nanoscale surface heterogeneities can be "hot spots" where anode passivation breaks down. Motivated by the observation of lithium dendrites in pores and grain boundaries in all-solid batteries, we examine lithium metal surfaces covered with Li(2)O and/or LiF thin films with grain boundaries in them. Electronic structure calculations show that, at >0.25 V computed equilibrium overpotential, L…
Lithium ion batteries (LIB) can feature reactive anodes that operate at low potentials, such as lithium metal or silicon, passivated by solid electrolyte interphase (SEI) films. SEI is known to evolve over time as cycling proceeds. In this modeling work, we focus on the stability of two main SEI components, lithium carbonate (Li2CO3) and lithium ethylene dicarbonate (LEDC). Both components are electrochemically stable but thermodynamically unstable near the equilibrium Li+/Li(s) potential. Interfacial reactions represent one way to trigger the intrinsic thermodynamic instability. Both Li(2)CO(…
A rechargeable lithium metal battery (LMB), which uses metallic lithium at the anode, is among the most promising technologies for next generation electrochemical energy storage devices due to its high energy density, particularly when Li is paired with energetic conversion cathodes such as sulfur, oxygen/air, and carbon dioxide. Practical LMBs in any of these designs remain elusive due to multiple stubborn problems, including parasitic reactions of Li metal with liquid electrolytes, unstable/dendritic electrodeposition at the anode during cell recharge, and chemical reaction of dissolved cath…
We developed two-step solution-phase reactions to form hybrid materials of Mn3O4 nanoparticles on reduced graphene oxide (RGO) sheets for lithium ion battery applications. Mn3O4 nanoparticles grown selectively on RGO sheets over free particle growth in solution allowed for the electrically insulating Mn3O4 nanoparticles wired up to a current collector through the underlying conducting graphene network. The Mn3O4 nanoparticles formed on RGO show a high specific capacity up to ~900mAh/g near its theoretical capacity with good rate capability and cycling stability, owing to the intimate interacti…
We report on the characterization of sol-gel derived lithium niobate via trivalent chromium probe ions, a study that is motivated by recent reports on the synthesis of high quality sol-gel lithium niobate (LiNbO$_3$). In order to assess the quality of sol-gel derived LiNbO$_3$, we incorporate Cr$^{3+}$ during the hydrolysis stage of the sol-gel process. A comparison of the Cr$^{3+}$ emission and photo-excitation data on both sol-gel and melt-grown LiNbO$_3$ shows that the sol-gel derived material is highly stoichiometric.
Here we report fabrication of flexible and stretchable battery composed of strain free LiFePO4 cathode, Li4Ti5O10 anode and a solid poly ethylene oxide (PEO) electrolyte as a separator layer. The battery is developed in a view of smart textile applications. Featuring solid thermoplastic electrolyte as a key enabling element this battery is potentially extrudable or drawable into fibers or thin stripes which are directly compatible with the weaving process used in smart textile fabrication. The paper first details the choice of materials, fabrication and characterisation of electrodes and a sep…
Nanoscale imaging reveals critical plating and stripping mechanisms in anode-free lithium and sodium solid-state batteries
Autonomous University of Madrid (UAM)（马德里自治大学）；Nicolás Cabrera University Institute of Materials Science (INC), UAM（尼古拉斯·卡布雷拉大学材料科学研究院（INC））；ALBA Synchrotron Light Facility（阿尔巴同步辐射光源设施）；Norwegian University of Science and Technology (NTNU)（挪威科技大学）；Fraunhofer Institute for Ceramic Technologies and Systems (IKTS)（弗劳恩霍夫陶瓷技术和系统研究所）；Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas (CSIC)（马德里材料科学研究所，西班牙国家研究委员会）；National Institute of Advanced Industrial Science and Technology (AIST), Research Institute for Energy Efficient Technologies（国立先进工业科学技术研究院，能源效率技术研究所）；Condensed Matter Physics Center (IFIMAC), UAM（凝聚态物理中心（IFIMAC））
The development of silicon anodes to replace conventional graphite in efforts to increase energy densities of lithium-ion batteries has been largely impeded by poor interfacial stability against liquid electrolytes. Here, stable operation of 99.9 weight% micro-Si (uSi) anode is enabled by utilizing the interface passivating properties of sulfide based solid-electrolytes. Bulk to surface characterization, as well as quantification of interfacial components showed that such an approach eliminates continuous interfacial growth and irreversible lithium losses. In uSi || layered-oxide full cells, h…
The decomposition of ethylene carbonate (EC) during the initial growth of solid-electrolyte interphase (SEI) films at the solvent-graphitic anode interface is critical to lithium ion battery operations. Ab initio molecular dynamics simulations of explicit liquid EC/graphite interfaces are conducted to study these electrochemical reactions. We show that carbon edge terminations are crucial at this stage, and that achievable experimental conditions can lead to surprisingly fast EC breakdown mechanisms, yielding decomposition products seen in experiments but not previously predicted.
Mg batteries utilizing a Mg metal anode with a high-voltage intercalation cathode define a potential pathway toward energy storage with high energy density. However, the realization of Mg batteries is plagued by the instability of existing electrolytes against the Mg-metal anode and high-voltage cathode materials. One viable solution to this problem is the identification of protective coating materials that could effectively separate the distinct chemistries of the metal-anode and the cathode materials from the electrolyte. Using first-principles calculations we map the electrochemical stabili…
In this work a new parameter for the Polymer Assisted Sol- Gel Deposition method is proposed. It is shaking of the sol stabilized by the polymer prior to the deposition. It was found in attempt to decrease the amount of [111]- oriented CeO2 grains on a monocrystalline substrate SrTiO3 (001). It was found that the shaking decreases this amount significantly.
We report the development of indium oxide (In2O3) transistors via a single step laser-induced photochemical conversion process of a sol-gel metal oxide precursor. Through careful optimization of the laser annealing conditions we demonstrated successful conversion of the precursor to In2O3 and its subsequent implementation in n-channel transistors with electron mobility up to 13 cm2/Vs. Importantly, the process does not require thermal annealing making it compatible with temperature sensitive materials such as plastic. On the other hand, the spatial conversion/densification of the sol-gel layer…
The Sm-activated orthvanadate nanoparticles were synthesized by co-precipitation and sol-gel methods. XRD study has shown that synthesized samples are characterized by monoclinic or tetragonal structure as well as their mixture dependently on Sm concentration and methods of synthesis. Influence of method of synthesis on morphology of nanoparticles, their absorption, diffuse reflectance and emission spectra was observed and studied.
Batteries are the most abundant form of electrochemical energy storage. Lithium and sodium ion batteries account for a significant portion of the battery market, but high-performance electrochemically active materials still need to be discovered and optimized for these technologies. Recently, tin(II) oxide (SnO) has emerged as a highly-promising battery electrode. In this work, we present a facile synthesis method to produce SnO nanoparticles whose size and shape can be tailored by changing the solvent nature. We study the complex relationship between wet chemistry synthesis conditions and res…
Sol-gel transition of carboxylated cellulose nanocrystals is investigated using rheology, SAXS, NMR and optical spectroscopies to unveil the distinctive roles of ultrasounds treatment and ions addition. Besides cellulose fibers fragmentation, sonication treatment induces fast gelling of the solution. Gelation is induced independently on the addition of cations, while the final rheological properties are highly influenced by the type, the concentration as well as on the sequence of the operations since salts must be added before sonication to produce stiff gels. Cations with various charge and …
Ce/Cr codoped TiO2 nanoparticles were synthesized using sol gel and Pechini methods with heat treatment at 400 C for 4 h. A conventional sol gel process produced well-crystallized anatase, while Pechini synthesis yielded less ordered mixed-phase anatase and rutile; this suggests that the latter method enhances Ce solubility and increases chemical homogeneity but destabilizes the TiO2 lattice. Greater structural disruption from the decomposition of the Pechini precursor formed more open agglomerated morphologies, while the lower levels of structural disruption from pyrolysis of the dried sol ge…
Amorphous polymer derived silicon oxycarbide (SiOC) is an attractive candidate for Lithium ion battery anodes, as an alternative to graphite, which is limited to a theoretical capacity of 372 mAh/g. However, SiOC tends to exhibit poor transport properties and cycling performance as a result of sparsely distributed carbon clusters and inefficient active sites. To overcome these limitations, we designed and fabricated a layered graphene SiOC heterostructure by solvent assisted infiltration of a polymeric precursor into a modified three dimensional graphene aerogel skeleton. The use of a high mel…
Recently "carbon ene-yne" (CEY), a novel full carbon two-dimensional (2D) material was successfully synthesized by the solvent-phase reaction. Motivated by this experimental effort, we conducted extensive first-principles density functional theory simulations to explore the application prospects of CEY as an anode material for Mg, Na and Li-ion batteries. To simulate the ionic intercalation process in an anode electrode, the adatoms coverage was gradually increased. We then employed Bader charge analysis to evaluate the charge transfer between the adatoms and the CEY nanosheet and finally to r…
New approach for obtaining ceramic NASICON (Na$_3$Zr$_2$ (SiO$_4$)$_2$PO$_4$) films sintered in situ by a sol-gel method, using spray deposition and Near-Infra Red Sintering
Piezoresponse force microscopy (PFM) was used to investigate the ferroelectric properties of sol-gel derived LiNbO$_3$ nanoparticles. To determine the degree of ferroelectricity we took large-area images and performed statistical image-analysis. The ferroelectric behavior of single nanoparticles was verified by poling experiments using the PFM tip. Finally we carried out simultaneous measurements of the in-plane and the out-of-plane piezoresponse of the nanoparticles, followed by measurements of the same area after rotation of the sample by 90$^{\circ}$ and 180$^{\circ}$. Such measurements bas…
Solid-state batteries (SSBs) can offer a paradigm shift in battery safety and energy density. Yet, the promise hinges on the ability to integrate high-performance electrodes with state-of-the-art solid electrolytes. For example, lithium (Li) metal, the most energy-dense anode candidate, suffers from severe interfacial chemomechanical issues that lead to cell failure. Li alloys of In/Sn are attractive alternatives, but their exploration has mostly been limited to the low capacity(low Li content)and In rich Li$_x$In (x$\leq$0.5). Here, the fundamental electro-chemo-mechanical behavior of Li-In a…
Ba0.6Sr0.4TiO3 nanoparticles were synthesized by the sol-gel method. The effects of the heat treatment conditions, ethylene glycol (EG) and deionized water (DW) on their phase structure and formation of the undesirable barium carbonate (BaCO3) phase were investigated. It was found that increasing the temperature of the samples caused an increase in the peak intensities of perovskite structures, and a decrease in the intensities of the BaCO3 peaks. Moreover, omitting EG, the sol stabilizer, and water, the solvent, decreased the peak intensities of BaCO3. Decreasing the heating rate caused bette…
Rate-Dependent Reversibility and Lithium Losses in Hybrid Anode-Collector Metal Electrodes
Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid（马德里自治大学凝聚态物理系）；Instituto Universitario de Ciencia de Materiales Nicolás Cabrera (INC), Universidad Autónoma de Madrid（马德里自治大学尼古拉斯·卡布雷拉材料科学大学研究所）；Centro de Micro-Análisis de Materiales (CMAM), Universidad Autónoma de Madrid（马德里自治大学材料微分析中心）；Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid（马德里自治大学凝聚态物理中心）
Herein, in-situ reduction of bismuth and graphene oxide was performed by a solvothermal method under a nitrogen atmosphere, and the resulting Bi on RGO nanocomposites were used as an anode material for Mg-ion batteries. The nanocomposite of 60% Bi:40% RGO is a beneficial anode material, delivering a discharge capacity as high as 413 and 372 mAh per g at the specific current of 39 mA per g in the 1st and 50th cycles, respectively. In addition, it shows high-rate capability with the discharge capacities of 381, 372, 354, 295, and 238 mAh per g at the specific currents of 53, 100, 200, 500, and 7…
Searching for three-dimensional(3D) semiconducting carbon allotropes with proper bandgaps and excellent optoelectronic properties is always the chasing goal for the new emerging all-carbon optoelectronics. On the other side, 3D carbon materials have also been recognized as promising anode materials superior to commercialized graphite in Li-ion batteries (LIBs). Here, using first-principles calculations, we propose two novel 3D carbon allotropes through acetylenic linkages modification of two structurally intimately correlated 3D carbon structures - carbon kagome lattice(CKL)and interpenetrated…
The effect of heavy tar compounds on the performance of a Ni-YSZ anode supported solid oxide fuel cell was investigated. Both toluene and naphthalene were chosen as model compounds and tested separately with a simulated bio-syngas. Notably, the effect of naphthalene is almost negligible with pure H2 feed to the SOFC, whereas a severe degradation is observed when using a bio-syngas with an H2:CO = 1. The tar compound showed to have a remarkable effect on the inhibition of the WGS shift-reaction, possibly also on the CO direct electro-oxidation at the three-phase-boundary. An interaction through…
Many key performance characteristics of carbon-based lithium-ion battery anodes are largely determined by the strength of binding between lithium (Li) and sp2 carbon (C), which can vary significantly with subtle changes in substrate structure, chemistry, and morphology. Here, we use density functional theory calculations to investigate the interactions of Li with a wide variety of sp2 C substrates, including pristine, defective, and strained graphene; planar C clusters; nanotubes; C edges; and multilayer stacks. In almost all cases, we find a universal linear relation between the Li-C binding …
Silicon is one of the most promising anode materials for Lithium-ion batteries. Silicon endures volume changes upon cycling, which leads to subsequent pulverization and capacity fading. These drawbacks lead to a poor lifespan and hamper the commercialization of silicon anodes. In this work, a hybrid nanostructured anode based on silicon nanoparticles (SiNPs) anchored on vertically aligned carbon nanotubes (VACNTs) with defined spacing to accommodate volumetric changes is synthesized on commercial macroscopic current collector. Achieving electrodes with good stability and excellent electrochemi…
A new experimental approach for in-situ Raman spectroscopy of the electrode | solid electrolyte interfaces in controlled atmospheres, based on the use of optically transparent single-crystal membranes of stabilized cubic zirconia, has been proposed and validated. This technique makes it possible to directly access the electrochemical reaction zone in SOFCs by passing the laser beam through single-crystal electrolyte onto the interface, in combination with simultaneous electrochemical measurements. The case study centered on the analysis of NiO reduction in standard cermet anodes under open-cir…
Using cryogenic transmission electron microscopy, we revealed three dimensional (3D) structural details of the electrochemically plated lithium (Li) flakes and their solid electrolyte interphase (SEI), including the composite SEI skin-layer and SEI fossil pieces buried inside the Li matrix. As the SEI skin-layer is largely comprised of nanocrystalline LiF and Li2O in amorphous polymeric matrix, when complete Li stripping occurs, the compromised SEI three-dimensional framework buckles, forming nanoscale bends and wrinkles. We showed that the flexibility and resilience of the SEI skin-layer play…
Zn metal battery has been considered a promising alternative energy storage technology in renewable energy storage and grid storage. It is well-known that the surface orientation of a Zn metal anode is vital to the reversibility of a Zn metal battery. Herein, the (101)-oriented thin Zn metal anode (down to 2 μm) is electrodeposited on a Cu surface by adding dimethyl sulfoxide (DMSO) electrolyte additive in ZnSO4 aqueous solution. Scanning electron microscope (SEM) observation indicates the formation of flat terrace-like compact (101)-oriented surfaces. Insitu optical observation confirms that …
Fluoroethylene carbonate (FEC) shows promise as an electrolyte additive for improving passivating solid-electrolyte interphase (SEI) films on silicon anodes used in lithium ion batteries (LIB). We apply density functional theory (DFT), ab initio molecular dynamics (AIMD), and quantum chemistry techniques to examine excess-electron-induced FEC molecular decomposition mechanisms that lead to FEC-modified SEI. We consider one- and two-electron reactions using cluster models and explicit interfaces between liquid electrolyte and model Li(x)Si(y) surfaces, respectively. FEC is found to exhibit more…
Photoluminescence is observed at room temperature from phonon-assisted band-to-band emission in Si (1.067 eV peak) using unpatterned bulk p-type silicon wafer samples that were spin-coated with Er-doped (6 at. %) silica-gel films (0.13 micron) and vacuum annealed; the strongest emission was obtained at ~700 degrees C. Comparative study of annealing behavior indicates two-orders of magnitude efficiency enhancement. Emission from Er+3 ions in the silica film is used to gauge relative emission strengths. Mechanisms for inducing emission from silicon utilizing stresses in sol-gel-films are discuss…
Microfluidics integrated with sol-gel processes is introduced in preparing monodispersed MOX nuclear fuel microspheres using nonactive cerium as a surrogate for uranium or plutonium. The detailed information about microfluidic devices and sol-gel processes are provided. The effects of viscosity and flow rate of continuous and dispersed phase on size and size distribution of CeO2 microspheres have been investigated. A comprehensive characterization of the CeO2 microspheres has been conducted, including XRD pattern, SEM, density, size and size distribution. The size of prepared monodisperse part…
The aim of this article is to decrease the crystallization temperature of the tetragonal perovskite PbTiO3 nanopowders below the PbTiO3 Curie temperature. At the beginning of our study, the calcination temperature was selected based on the thermal analysis of the PbTiO3 gels, came out at 680°C. However, reconsidering the thermal properties of the PbTiO3 gel revealed the possibility of the formation of single tetragonal perovskite phase at lower temperatures. Both X-Ray diffraction and transmission electron microscopy investigations showed that well crystalline pure phase PbTiO3 nanopowders hav…
Low cost and low thermal budget based spin-coated sol-gel Alumina was explored as a dielectric/passivation layer for GFET. Post thermal annealing, the crack was observed in sol-gel Alumina layer exactly above the graphene channel. The possible mechanism of crack could be graphene lateral restoring movement due to (i) Thermal Expansion Coefficient (TEC) difference between graphene and adjacent layers and (ii) shrinkage stress generated during the solvent removal process. Based on the crack formation phenomenon, a combination of different annealing schemes (low thermal budget DUV annealing) and …
Viscoelastic and thermodynamic properties of transient gels formed by telechelic polymers are studied on the basis of the transient network theory that takes account of the correlation among polymer chains via network junctions. The global information of the gel is incorporated into the theory by introducing the elastically effective chains according to the criterion by Scanlan and Case. We also consider effects of superbridges whose backbone is formed by several chains connected in series with several breakable junctions inside. Near the critical concentration for the sol/gel transition, supe…
Room-temperature 1535-nm-band photoluminescence in ~126 nm silica films (6 at. % doping), produced by spin-coating an Er2O3 and tetraethylorthosilicate sol-gel formulation on silicon substrates, was studied as a function of vacuum furnace annealing (500 to 1050 degrees C). Emission is strongly enhanced for annealing near 850 degrees C, which is shown by modeling the temperature dependence as arising from thermally-activated removal of hydroxyl ions. Suitability of such a process for silicon-based applications is discussed.
