Lithium Source Research Articles

Complexing Mechanistic Impacts on the Microstrucutre and Performances of LiFePO4 Synthesized Via Sol-Gel Approaches

Olivine structured LiFePO4 is an attractive cathode material for lithium ion batteries for its low cost, environmental benign, good cycling performance, safety, etc. It intrinsic low electronic conductivity and lithium-ion diffusion demands exquisite synthesis to produce small particles with surface electrical coating. Wet chemical sol-gel route have indisputable advantages over solid-state reactions for fabricating LiFePO4 fine particles with narrow size distribution, in addition to its ease of mass production and capabilities of in-situ carbon coating as well as flexible doping. Understanding of the influences of the key processing parameters like species of chelating agent and PH value of solution on the microstructure and performances of materials is fundamentally important. Here we report our studies on correlating the stability of complexing compounds on the mircrostructure of LiFePO4 products, carbon contents, and hence the electrochemical properties. LiOH.H2O and FeC2O4.2H2O were selected as the sources of lithium and iron. H3PO4 and/or NH4H2PO4 was the source of phosphate ions, which was also used to une the PH value of the sol. Basic complexing agents are citric acid (CA) and ethylene glycol (EG). In this work, individual complexing agent and the combination of the two with different ratios and their impacts on the product microstrucutre and electrochemical performances were investigated. The microstructure and composition of the LiFePO4/C products were investigated by means of X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive spectroscopy (EDS), and thermal graviemtric analyses (TGA) etc. For galvanostatic charge-discharge and electrochemical impedance spectroscopic analyses, the synthesized LiFePO4/C powders were mixed with conductive agent and binder at a certain mass ratio in solvent and coated on Al foil. Nanocrystalline LiFePO4/C materials with spherical particles of less than 500nm and appropriate amount of carbon coating were successfully obtained at the optimal synthesis parameters. It was found that carbon content remaining in the powder product after sintering varied from 10wt% and 1.2 wt%, depending on the chelating complex composition and the amount. A consistent trend was observed among the lithium-storage capacity, carbon content, and complex stability. The carbon content and the stability constants of the complex compounds are corroborative, while the Li-storage capacities of LiFePO4 products are inversely proportional to the stability constants of their corresponding complex compounds as well as the carbon content. It is well known that the types of central metallic ion and complex ligand have decisive influences on the stability of the formed complex compounds. The stability of complex compounds formed from Fe2+ are all small than that formed from Fe3+ with the same complex agent. The complex agent CA forms five or six-membered rings during the complex process, so the corresponding stability constants of the formed complex compounds are all relatively larger. Consequently, the product contains large amounts of carbon remnants. Excessive carbon on the surface of LiFePO4 will block the diffusion of Li into the LiFePO4 crystal structure, leading to the reduced lithium storage capacity and rate capability. The PH value of the precursor solution affects two main reactions, i.e. hydrolysis and polymerization, during the sol-gel process. Thereby, it affects the iorn valency and final particle size. Suitable PH environment is found to ensure uniform distribution of metal cations in the organic sol-gels leading to the uniformly fine and well dispersed LiFePO4 powders which are benefical to the high electrochemical performances.

The Application of Atomic Layer Deposition in Lithium-Ion Batteries

Lithium-ion batteries (LIBs) have been considered a promising energy storage system for various applications such as electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs). Intensive studies have been focused on improving LIBs in terms of power and energy density, cycling lifetime, safety characteristics, and cost. Atomic layer deposition (ALD) emerges as a powerful technique for addressing these issues due to its exclusive advantages over other thin film deposition techniques. Based on a self-limiting growth mechanism, ALD enables ultra uniform and conformal deposition of thin films and provides exquisite control of the thin film thickness down to angstrom. The advantages stand out more on high-aspect-ratio three-dimensional (3D) substrates due to the nature of the gas phase reactions [1, 2]. In LIBs, We first employed ALD to design nanocomposites used as electrode or solid-state electrolyte (SSE) materials, which can further be applied in the fabrication of 3D all-solid-state microbatteries [3]. Another application of ALD in LIBs is to deposit the ultra thin film on the electrode material as a surface modification in order to promote the performance of LIBs [4]. Our work also focuses on the development of lithium phosphate and lithium tantalum as SSE by ALD [5, 6]. The ALD processes have been established for both materials. LiOtBu is used as the lithium source. The as prepared thin films exhibit an amorphous structure. Electrochemical measurements are applied to characterize the ionic conductivity of these two thin films, which reaches an order of 10-8 scm-1. In addition, our work summarizes our recent study of engineering electrode/electrolyte interfaces by ALD. The complete surface coating acts an effective protection from the undesired side reactions (metal dissolutions in some cathode materials) and thus improves the capacity retention [6, 7]. The negligible thickness of the thin film allows ions to pass through. Besides, ALD prepared SSE (LiTaO3) as coating layers even benefits the transporting of lithium ions compared with simple binary oxide coatings such as Al2O3. [4] Furthermore, coatings with good toughness restrain the volume change of the electrode materials upon cycling, preventing pulverization. [8] We have been purposely developing different materials by ALD and combining them with LIBs. Lithium protection via ALD is another focus of our research. With fairly high energy density, lithium metal suffers from parasitic reactions with solvents, contaminations, and shuttled active species in the electrolyte. It has been reported that applying a thin chemical protection layer is a practical solution towards stabilizing lithium metal anodes in battery performances [9]. It has proven that ALD is a critical resort in the advances of next-generation LIBs in the future. [1] X. Meng, X. Yang, X. Sun, Adv. Mater. 2012, 24, 3589–3615 [2] J. Liu, X. Sun, Nanotechnology 2015, 26, 024001 [3] J. Liu, M. Banis, Q. Sun, A. Lushington, R. Li, T. K Sham, X. Sun, Adv. Mater. 2014, 26, 6472-6477 [4] X. Li, J. Liu, M. Banis, A. Lushington, R. Li, M. Cai, X. Sun, Energy Environ. Sci. 2014, 7, 768-778 [5] B. Wang, J. Liu, Q. Sun, R. Li, T. K Sham, X. Sun, Nanotechnology 2014, 25, 504007 [6] J. Liu, M. Banis, X. Li, A. Lushington, M. Cai, R. Li, T. K. Sham, X. Sun, J. Phys. Chem. C 2013, 117, 20260-20267 [7] B. Xiao, J. Liu, Q. Sun, B. Wang, M. Banis, D. Zhao, Z. Wang, R. Li, X. Cui, T. K. Sham, X. Sun, Adv. Sci. 2015, 1500022 [8] D. Wang, J. Yang, J. Liu, X. Li, R. Li, M. Cai, T. K. Sham, X. Sun, J. Mater. Chem. A 2014, 2, 2306-2312 [9] A. Kozen, C. Lin, A. J. Pearse, M. A. Schroeder, X. Han, L. Hu, S. Lee, G. W. Rubloff, Malachi Noked, ACS. Nano. 2015, 9, 5884-5892

Mechanochemical Synthesis of Lithium Sulfide for Li-S Batteries

Lithium–sulfur (Li–S) batteries are receiving intense interest because their promise for low-cost and high-energy electrochemical storage [1]. Sulfur has a high theoretical specific capacity (1675 mAh g−1) and energy density (2600 Wh kg−1). In addition, it is abundant, inexpensive and nontoxic. Despite these advantages Li-S batteries have not been commercially produced. Major drawbacks are the insulating nature of orthorhombic sulfur and its discharge product (Li2S), the dissolution of lithium polysulfide formed during the electrochemical process in organic liquid electrolyte, and the large volumetric expansion of sulfur during lithiation. These factors result in a low utilization of active material and poor cycle life [2]. Furthermore this kind of battery must use lithium metal as the anode. Fully-lithiated lithium sulfide (Li2S) is more desirable than sulfur as a high capacity cathode material because it allows the use of a variety of lithium-free anode materials. Recently, a number of studies on Li2S with promising results have emerged. Some authors ball-milled commercial Li2S to get different particle sizes, and the resulting particles are mostly micrometer-sized [3-4]. Furthermore, high-energy ball milling was also used for the preparation of compounds with improved chemical properties. Iio et al. [5] have synthesized lithium ion conducting materials in the system Li3N-SiS2 by mechanical milling at room temperature using Li3N as a lithium source. In the present study we synthesized Li2S by high energy ball milling using elemental sulfur and Li3N. To identify crystalline phases of samples, X-ray diffraction measurements (Rigaku Miniflex diffractometer) were performed for powdered samples after mechanical milling for a given period of time. In the figure below is showed the X-ray diffraction patterns of the sample obtained after 1 h of ball milling. It is possible to observe that the sulfur was completely converted into Li2S. The Scherrer's formula was used to evaluate the crystal size of the crystallite: d = k*λ/B*cosθ where d is the size of the crystallites, k is a constant that depends on the shape of the crystallites, λ is the wavelength of the radiation used, B is the peak width at half height and θ is the angle of diffraction of the peak. The value of the crystallite size calculated with the Sherrer’s formula was about 17-18 nm. The so obtained material was used to produce an electrode and the electrochemical properties were evaluated in a two electrodes lithium cell. LiClO4 dissolved in a mixture of ethylene glycol dimethyl ether and diethylene glycol dimethyl ether 50:50 was used as the electrolyte. We found that lithium can be electrochemically extracted and reversible reinserted into the material. The capacity was limited to about 180 mAh g-1 with a good capacity retention with cyclation . Further study will be addressed to increase the specific capacity of the material and to couple the electrode with suitable anode materials to obtain a full lithium-ion cell. A. Manthiram, S.H. Chung, C.X. Zu. Advanc. Mat. 2015, 27,1980-2006.M. Helen, M. Anji Reddy, T. Diemant, U. Golla-Schindler, R. J. Behm, U. Kaiser, and M. Fichtner. Scient. Rep. 20015, 5, 12146.K. Cai, M. Song, E. J. Cairns, Y. Zhang. Nano Lett. 2012, 12, 6474−6479.A. Manthiram, Y. Fu, Y. Su. Acc. Chem. Res. 2012, 46, 1125− 1134.K. Iio, A. Hayashi, H. Morimoto, M. Tatsumisago, and T. Minami, Chem. Mater. 2002, 14, 2444-2449. Figure 1

A Facile Route to Synthesis LiMPO4/Graphene Freestanding Cathode Electrodes for Lithium Ion Batteries

To globally solve the problem of an environmentally clean and secure distribution of energy is a major task for scientist worldwide. The use of clean energy will have a direct positive influence on, for example, the emission of greenhouse gases and our future climate. Today the rechargeable battery with the highest energy density is the Li-ion or Li-polymer battery. Commercially this battery is used for mobile phones, laptops and camcorders. The development of new batteries of this type has to go towards larger batteries for hybrid vehicles or towards further miniaturisation for smaller electronic devices. Both these routes will, however, require basic materials research within chemistry and physics; new materials must be synthesized (some materials used today are too expensive for up-scaling) and the complex chemistry occurring both in bulk electrode materials and at the interface between electrolyte and electrode most be better understood. Among different electrode materials, layered transition metal oxides (LMO) are the most successful cathode material in application at present time, but its further development is severely hindered due to the intrinsic safety limitation and the cost. Seeking for some other cost-effective cathode materials with better performance is a significant task. And therefore, olivine-structured phosphate LiMPO4 (M = Fe, Mn, Co, etc.) materials have attracted great attention due to many advantages, such as lower toxicity, lower cost, better thermal, chemical stability. Unfortunately, phosphate based cathode material possesses low intrinsic electronic and ionic conductivity. So, that it is difficult to prepare LiMPO4 (M: Fe, Mn, Co, etc) with a high performance, and many groups have explored various solutions to solve the problems, including enhancing the electronic conductivity among particles. In order to overcome these issues, studies are mostly focused on synthesis methods with a coating of an electronically conductive phase such as carbon. Another route to solve these problems could be done by using graphene. It has been reported that the two-dimensional graphene has unique properties such as excellent electrical and mechanical properties, unique physical properties such as high specific surface area (2630 m2/g), high electrical conductivity, a broad electrochemical window and good flexibility. Graphene oxide paper and graphene paper have been produced by vacuum filtration of graphene sheets. As a result, graphene free standing electrodes have been used directly as electrode materials for flexible energy storage devices without binder, conductive additives and current collectors. As compared with conventional electrodes, free-standing electrodes can increase the electrical conductivity of electrode materials meanwhile achieve higher active material-to-substrate mass ratios. In this study, a microwave hydrothermal synthesis process is used to produce novel, and facile strategy for the preparation of LiMPO4 (M=Mn, Fe, and Co) microstructures at a low temperature, using ethanol as the solvent, LiI as the lithium source, transitional metal salt as the M sources, H3PO4 as the phosphorous source, and poly(vinyl pyrrolidone) as the carbon source and template. As-synthesized LiMPO4 were then subjected to vacuum filtration techniques with graphene in order to obtain freestanding cathode electrodes for high capacity Li-ion batteries. Keywords: LiMPO4, graphene, freestanding electrode, cathode electrode, Li ion.

Electrochemistry Characteristics of NaNi0.5Mn1.5O4 As the Cathode Material for Sodium Ion Batteries

Introduction Lithium ion batteries have been widely used in portable electronic devices and deploying in electric vehicles and power grid energy storing. After the topic of the limited lithium source was mentioned, sodium ion batteries resurged in recent years. Many kinds of cathode materials for sodium ion batteries have been studied, but more research is needed to realize the commercial use of sodium ion batteries, especially competing with current lithium ion batteries. Because of large ion size, Na+ cannot stay in tetragon position in close-packed oxygen structure, so spinel structure of sodium oxide isn’t thermal stable phase, which can only synthesized at high pressure[1]. Naoaki Yabuuchi et al. [2] reported that product of electrochemical exchanged LiMn2O4 isn’t NaxMn2O4, but NaMnO2. The NaMnO2 prepared by electrochemical exchange show a very high capacity of 190 mAh/g and better capacity retention in the 2.3-4.3V range than the directly prepared NaMnO2. Here we report the structure change and electrochemical performance of NaNi0.5Mn1.5O4 prepared by electrochemical exchange method. Experimental Spinel LiNi0.5Mn1.5O4 was prepared by solid state method. Stoichiometry Li2CO3, Ni(OH)2 and Mn2O3 were ball-milled and then sintered at 800℃ for 24h in air. The obtained LiNi0.5Mn1.5O4 was chartered by XRD, SEM and charge-discharge testing. For preparation of NaNi0.5Mn1.5O4 via electrochemical exchange, LiNi0.5Mn1.5O4 was first charged to 4.9V in a cell with Li electrolyte and Li anode to de-insert all of the lithium ions. Then the cell was disassembled and the cathode electrode was took out and washed by DMC for three time followed by assembling it with Na electrolyte (NaClO4 in PC+FEC) and Na anode. Charge and discharge the sodium ion cell at 10 mA/g current between 2 and 4.5V. Results and discussion LiNi0.5Mn1.5O4 shows a long charge plateau at 4.7V in lithium cell, which represents de-intercalation of Li+ and oxidation of Ni2+. At the end of charge process, Ni0.5Mn1.5O4 with very few lithium ions was gotten whose character of Na+ intercalation and de-intercalation was investigated in following cycles in sodium cell. It could be found that a discharge plateau at about 3.6V corresponding about a capacity of 80 mAh/g (Fig.1a). The electrochemical behavior is similar as the NaMn2O4 whose initial discharge plateau locates at about 3.2V with a capacity of 80 mAh/g in sodium cell [2]. However, in NaNi0.5Mn1.5O4 system, the capacity between 2 and 3V is little, so the total capacity is only about 110mAh/g for the first discharge process and decrease quickly during the following cycles. The structure of cycled NaNi0.5Mn1.5O4 was investigated by XRD, shown in Fig.1b. The spinel structure is kept when lithium ion is replaced by sodium ion, though some should peaks appears, which caused by strain because of a size gap between Li+ and Na+. After cycling, though no peaks corresponding to layered NaMnO2 can be found, the capacity decreases obviously, so new capacity decrease mechanism should be considered. Reference [1] Xizheng Liu, Xi Wang, Akira Iyo, et al., J. Mater. Chem. A, 2014, 2, 14822-14826 [2] Naoaki Yabuuchi, Masaya Yano, Satoru Kuze, et al., Electrochim. Acta, 2012,82, 296–301 Figure 1

A New Strategy to Mitigate the Initial Capacity Loss of Lithium Ion Batteries

Electrode materials and electrolyte choices largely dictate the design parameters and the type of lithium-ion battery (LIB) that can be optimized and eventually utilized. Certainly all three components (anode, electrolyte, and cathode) must work in harmony to produce the highest possible energy density achievable for an LIB-based energy storage device. Balancing the electrochemical performance characteristics of the cathode and anode active materials is critical for maximizing the power/energy density of a LIB. Hard carbon (non-graphitizable) anode materials, like tin, tin oxide, silicon and silicon oxide, have a high theoretical capacity (>550 mAh/g depending on their structural and chemical properties) but unfortunately they also exhibit a large initial capacity loss (ICL), which overrides the true reversible capacity in a full cell. Overcoming the large ICL of hard carbon in a full-cell lithium-ion battery (LIB) necessitates a new strategy wherein a sacrificial lithium source additive such as Li5FeO4 (LFO) is used on the cathode side. Full batteries using hard carbon coupled with LFO/LiCoO2 (LCO) are currently under development at our laboratory. We find that the reversible capacity of a cathode containing LFO can be increased by 24%. Furthermore, the cycle performance of full cells with LFO additive is improved from <90% to >95%. We believe that the LFO can not only address the irreversible capacity loss of the anode, but can also provide the additional lithium ion source required to mitigate the lithium loss caused by side reactions. In addition, we have explored the possiblity to achieve higher capacity on hard carbon, whereby the energy density of full cells can be increased from ca. 300 Wh/kg to >400 Wh/kg .

Transition-Metal Pyrophosphates As Cathodes for Rechargeable Na-Ion Batteries: Effects on the Electrochemical Properties of Composition and Preparation Methods

The urgency of decreasing atmosphere pollution is driving industry toward more environmentally-friendly power sources, including solar, wind and hydro. As intermittent renewable energy technologies will become prevalent and integrated into the electrical grid, however, availability of large-scale storage systems will be crucial. At present, Li-ion batteries (LIBs) are one of the most encouraging technologies. On the other hand, grid-scale storage requires low cost, safety, and eco-friendly devices, and LIBs are approaching their technical limits combined with fast lithium sources pauperisation. Therefore, other chemistries must be considered, and Na-ion batteries (SIBs) are under rapidly development. In this context, materials for Na-ion batteries, in particular cathodic ones, are the subject of a growing research interest. [1,2] Among the cathode materials which are currently proposed for use in Na-ion batteries, an interesting family is that of sodium metal pyrophosphates having general formula Na2MP2O7(M = Co, Cu, Fe, Mn).[3] In fact, chiefly when Fe is employed as the transition metal, all the involved elements are non-toxic, abundant and environmentally-friendly. Pyrophosphate-based cathodes are normally prepared by means of a solid-state reaction process, possibly followed by reduction of the particle size and carbon coating. [4] In this study we focused our attention both on the Mn-Fe substitution and on the relationships among synthesis procedure and functional properties in determining the electrochemical properties of the cathode material. The solid solution Na2Fe1−x Mn x P2O7 (x = 0, 0.25, 0.5, 0.75, 1) was prepared by conventional solid-state reaction. In addition, the Na2FeP2O7 end-member was also prepared through different synthetic procedures: glucose-assisted, solid-state reaction and wet-chemistry (citrate) methods. The materials were characterized for what concerns their structural, morphological and electrochemical process through X-ray diffraction, scanning electron microscopy, cyclic voltammetry, charge/discharge curves. The results show that the system forms a complete solid solution over the entire composition range. The electrochemical performances are severely affected by the increase of Mn content, at least in the case of conventional high temperature solid-state reaction and standard slurry preparation. [5] The electrochemical results are compared and discussed in terms of morphological considerations. Interestingly, the electrochemical behavior of the Na2FeP2O7 compound is strongly dependent upon the preparation method, especially for high C-rates. This is consistent with the fact that different preparation methods can modulate the morphological properties and the carbon coating of the material.

Effect of Calcination Temperature on the Characterizations of P-Type Na0.6Mn0.65Ni0.25Co0.10O2 Cathode Materials in Sodium-Ion Batteries

Recently, the demand for energy storage devices for electricity supply has been increasing remarkably. Lithium-ion batteries have already been popular power supplies for devices such as mobile phones, notebooks, digital devices and hybrid vehicles and so on. This increases the rate of lithium consumption; therefore, its cost has risen because of lithium source problem. Owing to abundant sodium resource and its low cost in comparison with lithium, sodium-ion batteries are promising for energy storage devices. Concerning cathode materials, layered NaxMO2 are classified into two main groups (O3 type or P2 type) in which the sodium ions are accommodated at octahedral and prismatic sites, respectively. Many works reported that P2-type structure exhibits a higher capacity and cyclability than O3-type structure. In this work, P-type Na0.6Mn0.65Ni0.25Co0.10O2 cathode materials were synthesized by a co-precipitation method. Effect of calcination temperature on the morphology, crystalline structure and electrochemical properties were investigated. Both P3-type (700 oC) and P2-type (800-1000 oC) structures were obtained at different calcination temperatures. In the cycling process, the P3-type material revealed a high discharge capacity of 136 mAh g-1 but a poor cycling performance. In contrast, the P2-type synthesized at 900 oC gave a highest specific discharge capacity of 148 mAh g-1and a more stable cycling performance and a good rate capability between 2.1 and 4.3 V. Acknowledgement This work was supported by the Human Resource Training Program for Regional Innovation and Creativity through the Ministry of Education and National Research Foundation of Korea (NRF-2014H1C1A1066977).

Water Accompanying Hydrocarbon Deposits as a Potential Source of Iodine, Lithium and Strontium

Abstract Oil and natural gas fields are accompanied by formation waters, usually highly mineralized brines containing a variety of trace elements. Analyses carried out in various sedimentary basins around the world indicate that these waters are often enriched in elements such as iodine, lithium and strontium. Currently, these micronutrients are finding increasing application in the production of lithium-ion batteries and lithium batteries (lithium) and in the pharmaceutical, medical and pharmaceutical industry (iodine). Due to the development of production of LCD displays and batteries (e.g. for electric cars), the expected increase in demand for iodine and lithium is 2% and 1.5%, respectively. The reserves of these elements are limited and unevenly distributed. Iodine is currently produced in the three countries: Chile (65% of the world production), Japan and the US. Lithium is produced in Argentina, Australia and Chile, while strontium is produced in China (50% of the global production), Spain and Mexico. Iodine, lithium and strontium are not produced in Poland and the total demand is met by imports. Brines with high iodine content, occurring in the hydrocarbon deposits, have been found in oil basins in the United States, Canada and Germany. In the United States, this element is recovered from formation water. Lithium found in numerous formation waters in the US, Canada, Japan and Germany has not yet been recovered, while the construction of the pilot plant in Canada is underway. The increased strontium content has been found in waters accompanying hydrocarbon deposits in North America and China. However, strontium has not yet been recovered from the aforementioned deposits. In Poland, the question of possible use of chemical elements dissolved in reservoir brines, with the exception of iodine, has not yet been studied. The above mentioned element (iodine) was recovered from brines in the area of Bochnia (Carpathian Foredeep), the only geological unit where an analysis of iodine content in the formation waters has been carried out in the recent years. The lithium and strontium content in the formation waters, as well as the question of their possible use, have not yet been studied.

A new strategy to mitigate the initial capacity loss of lithium ion batteries

Hard carbon (non-graphitizable) and related materials, like tin, tin oxide, silicon, and silicon oxide, have a high theoretical lithium delivery capacity (>550 mAh/g depending on their structural and chemical properties) but unfortunately they also exhibit a large initial capacity loss (ICL) that overrides the true reversible capacity in a full cell. Overcoming the large ICL of hard carbon in a full-cell lithium-ion battery (LIB) necessitates a new strategy wherein a sacrificial lithium source additive, such as, Li5FeO4 (LFO), is inserted on the cathode side. Full batteries using hard carbon coupled with LFO-LiCoO2 (LCO) are currently under development at our laboratory. We find that the reversible capacity of a cathode containing LFO can be increased by 14%. Furthermore, the cycle performance of full cells with LFO additive is improved from <90% to >95%. We show that the LFO additive not only can address the irreversible capacity loss of the anode, but can also provide the additional lithium ion source required to mitigate the lithium loss caused by side reactions. In addition, we have explored the possibility to achieve higher capacity with hard carbon, whereby the energy density of full cells can be increased from ca. 300 Wh/kg to >400 Wh/kg.

Synthesis of Li4Ti5O12-reduced graphene oxide composite and its application for hybrid supercapacitors

We describe in this paper the synthesis and the characterization of Li4Ti5O12-reduced graphene oxide (LTO-RGO) composite and demonstrate their use as hybrid supercapacitor, which is consist of an LTO negative electrode and activate carbon (AC) positive electrode. The LTO-RGO composites were synthesized using a simple, one-step process, in which lithium sources and titanium sources were dissolved in a graphene oxide (GO) suspension and then thermal treated in N2. The lithium-ion battery with LTO-RGO composite anode electrode revealed higher discharge capacity (167 mAh g−1 at 0.2 C) and better capacity retention (67%) than the one with pure LTO. Meanwhile, compared with the AC//LTO supercapacitor, the AC//LTO-RGO hybrid supercapacitor exhibits higher energy density and power density. Results show that the LTO-RGO composite is a very promising anode material for hybrid supercapacitor.

Transverse laser cooled Lithium atomic beam for plasma edge diagnostics

We have built a set up to achieve a collimated atomic Lithium beam to be used for plasma edge diagnostics. The collimation is achieved by two-dimensional laser cooling, and such a beam could be very useful to obtain electron density at the edge of a plasma with very high spatial resolution. We present in this manuscript the details of this setup, including details of the oven we designed for the Lithium source. We present the metrics of the beam, including the transverse velocity profile of the atomic beam.

Role of Superoxide Anion in the Oxygen Reduction Reaction in Non-Aqueous Electrolytes with a Proton or Lithium Source

The non-aqueous Li-air (O2) battery has generated a great deal of research interest because it potentially possesses far greater gravimetric energy storage density than today’s rechargeable battery technologies.1-4 Presently non-aqueous Li-O2 batteries suffer from irreversible reactions, including those due to impurities such as residual protons and proton-containing compounds that can react with reduced oxygen species. To eliminate or alleviate the undesired reactions, it is crucial to have a fundamental understanding of the reactive oxygen species involved in the oxygen reduction reaction (ORR). In this talk we will present the results of a series of electrochemical studies of the ORR on a gold electrode in non-aqueous dimethyl sulfoxide (DMSO) electrolytes containing a proton or lithium source with TBAClO4 as supporting ions. The superoxide anion (O2 -), the one-electron reduction product of O2, is identified in situ spectroscopically in both systems. When the DMSO contains phenol as the proton source, O2 -, not HO2, appears as the first stable intermediate during the ORR upon cathodic scans, with H2O2 co-appearing at high overpotentials.5 When instead LiClO4 is added to DMSO, again O2 - is the first reaction intermediate to be detected, whereas surface LiO2 does not appear until the potential is much more negative of the Li2O2 formation potential. The stability of O2 - vs. the other reduced O2 species is rationalized based on first-principles theoretical modelling and calculations. Our studies show that the ORR mechanism depends intimately on the electrode potential and electrolyte composition, and contribute new mechanistic understanding for this reaction that is of fundamental importance to electrochemical energy storage and conversion technologies. 1. P.G. Bruce, S.A. Freunberger, L.J. Hardwick, J.-M. Tarascon, Nat. Mater. 2012, 11, 19. 2. J. Lu, L. Li, J.-B. Park, Y.-K. Sun, F. Wu, K. Amine, Chem. Rev. 2014, 114, 5611. 3. A.C. Luntz, B.D. McCloskey, Chem. Rev. 2014 , 114, 11721. 4. R. Black, B. Adams, L.F. Nazar, Adv. Energy Mater. 2012, 2, 801 5. Z. Peng, Y. Chen, P.G. Bruce, Y. Xu, Angew. Chem. Int. Ed. 2015, 54, 8165.

Intense antineutrino source based on a lithium converter. Proposal for a promising experiment for studying oscillations

An intense electron-antineutrino source with a hard spectrum (\(E_{{{\tilde v}_e}}^{\max }\) = 13 MeV and \(\left\langle {{E_{{{\tilde v}_e}}}} \right\rangle \) = 6.5MeV) can be created on the basis of the short-lived isotope 8Li (β−-decay, T1/2 = 0.84 s) formed via the (n, γ) activation of 7Li. In contrast to a reactor antineutrino spectrum whose uncertainty is large, particularly in the high-energy region \({E_{{{\tilde v}_e}}}\) > 6 MeV, which is experimentally relevant, the lithium \({\tilde v_e}\) spectrum is accurately determined. The proposed accelerator-driven experimental scheme with a neutron-producing target and a lithium converter as an intense \({\tilde v_e}\) source is an alternative to a nuclear reactor. The required amount of high-purity 7Li will be reduced in many times by using the suggested heavy-water LiOD solutions. A possible experiment involving the lithium source on search for sterile neutrinos in the mass region Δm2 ≥ 0.2 eV2 with a very high sensitivity to mixing-angle values down to sin2(2Θ) ≈ (7–10) × 10–4 at the 95% C.L. has been considered.

The effect of ceramic synthesis conditions on the electrochemical properties of Li2Ti3O7

Different ceramic synthesis conditions of ramsdellite Li2Ti3O7 have been investigated in order to determine the influence on the electrochemical performances as the negative electrode of lithium-ion batteries. Lithium source, thermal pretreatment, synthesis temperature, and time of reactions were the analyzed conditions. A convenient and cheap reagent like Li2CO3 treated with TiO2 at high temperature (1250 °C) for very short time (2 h) provides a reliable active material. When tested versus lithium, the initial specific capacity (150 mAh g−1) is lower than that of ceramic samples prepared at lower temperature or for longer treatment times (ca. 170 mAh g−1). The lower initial capacity is attributed to the large particle size obtained at high temperature. However, advantageously the capacity retention of the former is superior. Thus, 115 mAh g−1 at C/20 rate is fairly kept (77 % retention) after 100 cycles. The better cyclability of samples prepared at high temperature (with large particle size) is likely due to lower surface reactivity that compensates the lower initial discharge capacity when cycling. A compromise between high initial capacity and capacity retention must be reached when using Li2Ti3O7 as a battery electrode. The good behavior of the optimized material is shown by testing it against commercial LiCoO2 as the positive electrode. The high capacity (ca. 135 mAh g−1) and outstanding cyclability observed prove that optimized ramsdellite may be effectively used as a long-life negative electrode material.

Preparation of H2TiO3-lithium adsorbent by the sol–gel process and its adsorption performance

CH3COOLi and Ti(OC4H9)4 were employed as lithium and titanium sources, respectively to synthesize Li2TiO3 by the sol–gel process, followed by treating with hydrochloric acid to yield H2TiO3-lithium adsorbent. Various concentrations of LiOH and lithium sources were used as adsorption liquid to carry out adsorption experiment, the data from which were analyzed by Langmuir and Freundlich models. The results indicate that the optimal calcination temperature is 650°C, and Li2TiO3 with particle size 60–80nm is observed. The Li+ drawn out ratio from Li2TiO3 reaches 78.9%, and the dissolution of titanium ions can be as low as 0.07%. The protonated sample obtained has a lower basal spacing, while the crystal morphology is retained. The main factors affecting the adsorptive capacity are the Li+ concentration and pH in the liquid. The adsorption process of H2TiO3-lithium adsorbent can be seen as a process including surface adsorption and ion exchange. Compared with Langmuir model, Freundlich model is more suitable for describing the actual adsorption process.

Synthesis and ionic transport mechanisms of α-LiAlO2

The pure phase α-LiAlO2 is synthesized by a solid-state reaction. The obtained product has nanocrystalline structure with the Li deficient regions near the surfaces. Combining X-ray diffraction (XRD) and thermogravimetry-differential scanning calorimetry (TG-DSC), the synthesis mechanism is revealed. The measured room-temperature ionic conductivity of the α-LiAlO2 ceramic pellet is as low as 10−21S·cm−1. This could be caused by the absence of conduction pathways, as calculated from the bond-valence (BV) method. In addition, a first-principles calculation is performed. The calculated result suggests that although the α-LiAlO2 bulk has the extremely low ionic conductivity, its ionic conductivity could be increased significantly when applied the bias voltage, which is due to the introduction of external lithium sources (lithium reservoirs of interstitials/vacancies) and external charge sources (electrons/holes). This may explain why α-LiAlO2 as the coating layer on cathode for Li-ion batteries does not block the transport of lithium ions.

In Situ Chemical Synthesis of Lithium Fluoride/Metal Nanocomposite for High Capacity Prelithiation of Cathodes.

The initial lithium loss during the formation stage is a critical issue that significantly reduces the specific capacity and energy density of current rechargeable lithium-ion batteries (LIBs). An effective strategy to solve this problem is using electrode prelithiation additives that can work as a secondary lithium source and compensate the initial lithium loss. Herein we show that nanocomposites of lithium fluoride and metal (e.g., LiF/Co and LiF/Fe) can be efficient cathode prelithiation materials. The thorough mixing of ultrafine lithium fluoride and metal particles (∼5 nm) allows lithium to be easily extracted from the nanocomposites via an inverse conversion reaction. The LiF/Co nanocomposite exhibits an open circuit voltage (OCV, 1.5 V) with good compatibility with that of existing cathode materials and delivers a high first-cycle "donor" lithium-ion capacity (516 mA h g(-1)). When used as an additive to a LiFePO4 cathode, the LiF/Co nanocomposite provides high lithium compensation efficiency. Importantly, the as-formed LiF/metal nanocomposites possess high stability and good compatibility with the regular solvent, binder, and existing battery processing conditions, in contrast with the anode prelithiation materials that usually suffer from issues of high chemical reactivity and instability. The facile synthesis route, high stability in ambient and battery processing conditions, and high "donor" lithium-ion capacity make the LiF/metal nanocomposites ideal cathode prelithiation materials for LIBs.

Effect of sol-gel process parameters on the properties of a Li1.3Ti1.7Al0.3(PO4)3 solid electrolyte for Li-ion batteries

In this study, the influence of the processing parameters, such as the synthesis temperature and the lithium sources on the structure, particle size, morphology and ionic conductivity of Li1+xTi2−xAlx(PO4)3 (LTAPO) was investigated. LiNO3, LiCl, and Li acetate were employed as lithium sources for investigating the effects of Li sources on the properties of the solid electrolyte. The morphologies and the particle size distribution of the prepared LTAPO samples were analyzed by using scanning electron microscopy (SEM) and a laser particle size analyzer. Their crystallinities were measured by means of X-ray diffraction (XRD). An increase in the synthesis temperature caused a pronounced growth in the particle size without any impurities, especially at temperatures above 700 °C. In addition, LiCl lithium sources showed the highest particles size. The effect of the processing parameters on the ionic conductivity of the prepared LTAPO was investigated by using electrochemical impedance spectroscopy (EIS). The ionic conductivities of the LTAPO prepared by using an optimized synthesis temperature with different lithium sources were 8.36 × 10−4, 5.73 × 10−4, and 7.18 × 10−4 S/cm for C-LTAPO, A-LTAPO, and N-LTAPO, respectively. The properties of the ceramic solid electrolyte were shown to be affected by the choice of the synthesis temperature and the Li source material.

挥发诱导自组装制备多孔Li&lt;sub&gt;4&lt;/sub&gt;SiO&lt;sub&gt;4&lt;/sub&gt;材料

本文以氢氧化锂(LiOH•H2O)为锂源、正硅酸乙酯(TEOS)为硅源、去离子水为溶剂、十六烷基三甲基溴化氨(CTAB) + 聚丙烯酸(PAA)为复合模板剂，采用挥发诱导自组装法(EISA)经高温焙烧制备多孔Li4SiO4 材料。利用X射线粉末衍射(XRD)和扫描电子显微镜(SEM)对材料的结构特征与表面形貌进行表征，用N2吸脱附考察材料的孔结构，在热重分析仪(TG)上研究Li4SiO4材料高温下的CO2吸收性能和循环稳定性。实验结果表明，以CTAB + PAA为复合模板剂，60℃溶剂挥发诱导自组装制备的Li4SiO4材料在550℃、0.25 bar下5 min内吸收量可达22.5 wt%，且在10 min内达到吸收平衡，平衡吸收量为28.8 wt.％，经5次吸收–解吸后仍保持初始吸收性能，显示了良好的循环稳定性。 A solvent evaporation induced self-assembly (EISA) method followed by calcination was employed to prepare porous Li4SiO4 materials by using LiOH•H2O, TEOS, deionized water, and CTAB + PAA as lithium source, silicon source, solvent, and composite template, respectively. X-ray powder dif-fraction (XRD) and scanning electron microscope (SEM) were applied to characterize the structure and morphology of the as-prepared Li4SiO4 materials. The pore structures of the Li4SiO4 materials were investigated by the N2 adsorption-desorption analysis. CO2 uptakes and recycle stability of the prepared Li4SiO4 materials were investigated on a thermogravity (TG) analyzer. The sample synthesized by the EISA method at 60˚C displays CO2 uptakes up to 22.5 wt% within 5 min. Addi-tionally, an absorption equilibrium of 28.8 wt% can be available within 10 min at 550˚C and a CO2 partial pressure of 0.25 bar. After five absorption-desorption cycles, the Li4SiO4 material keeps its original CO2 absorption properties, indicating a good cycle stability.