Lithium Tin Research Articles

Controllable hydrogen generation at low temperatures and safety evaluation for tin anode materials of spent lithium-ion batteries

Given the environmental pollution and thermal risks of lithium-ion batteries, it is necessary to recycle and evaluate the safety of spent lithium-ion batteries. Here, lithium tin alloys (LixSny) were prepared via mechanical alloying to simulate the tin anode materials at different lithium-embedded states. Among them, the Li22Sn5 alloy showed the optimum hydrolysis performance, releasing 351 mL g−1 hydrogen in 10 s at 293 K. The safety evaluation was carried out based on hydrolysis performance, maximum adiabatic temperature rise, and other parameters. The Li22Sn5 alloy required 738.8 mL of water to cool down to 303 K. Moreover, the reaction rates can be precisely controlled by tailoring the solution components, which effectively promoted the security and controllability for practical application. In addition, the hydrogen production of Li22Sn5 sample after hydrogenation increased to 624 mL g−1, even at a subzero temperature of 243 K, 510 mL g−1 hydrogen can be generated within 30 s. This study provides a new idea for the safety evaluation and recycling of tin anode materials in spent lithium-ion batteries.

Stretchable battery can power a smart watch

A lithium-ion battery made of gels and composites can be stretched to 1.5 times its original length and still work, even after 1,000-plus tugs, researchers report in a new study ( ACS Nano 2022, DOI: 10.1021/acsnano.1c08405 ). Because all the materials start as pastes, the battery can also be printed directly on fabric, says study coauthor Jeong Gon Son of the Korea Institute of Science and Technology. The new battery is the first in which every part—electrodes, separator, current collectors, and outer cover—is made of intrinsically elastic materials , Son says. The heart of the battery consists of stacked films of an organogel made of poly(vinylidene fluoride) fibers soaked in acetone. To make the cathode, Son and his colleagues add lithium iron phosphate to the gel; to make the anode, they add lithium tin oxide particles. A gel film soaked in electrolyte separates the electrodes from each other. Polyisobutylene films

The Lithium Iodostannate LiSn3I7: Synthesis, Properties and its Relationship to SnI2

AbstractThe mixed lithium tin iodide LiSn3I7 was prepared by reacting LiI and SnI2 at 300 °C. Single‐crystal X‐ray diffraction revealed a crystal structure related to that of SnI2, with nearly identical coordination environments of tin atoms. The lithium ion in the structure of LiSn3I7 shares one crystallographic position with a tin atom in octahedral voids of (LiSn)Sn2I7, as confirmed by solid‐state 7Li, 119Sn and 127I MAS NMR spectra. DFT band structure calculations show LiSn3I7 to be a semiconductor with an indirect bandgap on the order of 2 eV.

In Situ and Ex Situ diagnostics of ALD-Ultrathin Lithium-Ion Films

All solid-state ion layers has an ever-growing interest in order to accomplish on-chip energy storage devices. As such, lithium-ion synaptic transistor to build artificial neural networks, integrated area-enhanced capacitors and lithium-ion microbatteries for energy supply are suitable candidates fulfilling energy-efficient devices. Atomic layer deposition (ALD) is one of the most promising techniques for manufacturing ultrathin layers for lithium-ion devices with exceptional capabilities to enable conformal growth at atomic scale. In this area, in situ diagnostics has become of vital importance for the growth process understanding especially on view of the air-sensitivity character of lithium ultra-thin layers.The purpose of this work is to present an in situ spectroscopic ellipsometry (SE) study of ALD thin films used on the fabrication of lithium-ion devices. We will consider several aspects of ALD ultrathin films growth, such as film thickness, saturation curves and initial films nucleation. We shall compare in situ SE results with those of ex situ diagnostics such as XRR (x-ray reflectometry) and XPS (x-ray photoelectron spectroscopy).We focus on the characterization of 10-100 nm thin lithium phosphate electrolyte with and without nitrogen doping deposited at ALD temperature range 300-350°C using LiHMDS-TMPO and LiHMDS-DEPA precursors, respectively. On the other hand, the realization of silicon integrated lithium ionic devices requires the implementation of essential barrier films to prevent Li-ion into the Si substrate. We will explore here the ability of titanium nitride depositions to act as lithium-ion diffusion barriers. TiN deposition (10-20 nm thin) by ALD process (350°C-400°C) uses TiCl4 and NH3 precursors.First, we investigate the growth process of LiPO, LiPON and TiN intrinsic layers deposited using thermal ALD. Secondly, we apply in situ and ex situ diagnostics on exemplary LiPO/LiPON deposited on top of the 10 nm ALD TiN film (Figure 1: Monitoring of LiPON thickness vs deposition time using in-situ Ellipsometry). The film thickness deduced from in situ SE measurements was corroborated by thickness measurements with XRR technique (Figure 2: Evolution of LiPON thickness vs ALD cycles using Ellipsometry and SE characterization techniques). Ex situ SE was used most often for WiW uniformity evaluating (Figure 3: 8” Wafer thickness mapping of ALD LiPON layers (a: 10nm TiN film; b: 17nm LiPON film). The preliminary results underline the fact that ALD growth rate and nucleation of lithium electrolyte and titanium nitride obviously depends on the ALD process parameters (temperature, pulse and purge times, number of cycles) but on the substrate nature (silicon, thermal oxide, and metallic). In situ and ex situ diagnostics highlight that initial film growth of lithium electrolytes and TiN layers strongly depends on the precursors kind used in the ALD process and the substrate material employed. Figure 1

Fast Water-Assisted Lithium Ion Conduction in Restacked Lithium Tin Sulfide Nanosheets

While two-dimensional (2D) materials may preserve some intrinsic properties of the corresponding layered bulk material, new characteristics arise from their pronounced anisotropy or confinement effects. Recently, exceptionally high ionic conductivities were discovered in 2D materials such as graphene oxide and vermiculite. Here, we report on the water-assisted fast conduction of lithium ions in restacked lithium tin sulfide nanosheets. Li0.8Sn0.8S2 exfoliates spontaneously in water and can be restacked into homogeneous films in which the lithium content is decreased, and a partial substitution of sulfur with hydroxyl groups takes place. Using a recursive supercell refinement approach in reciprocal space along with real-space pair distribution function analysis, we describe restacked lithium tin sulfide as a partially turbostratically disordered material composed of lithium-containing and lithium-depleted layers. In humid air, the material takes up multiple layers of water that coordinate lithium ions in the space between the layers, increasing the stacking distance and screening the interaction between lithium ions and the anionic layers. This results in a 1000-fold increase in ionic conductivity up to 47 mS cm–1 at high humidities. Orientation-dependent impedance spectroscopy suggests a facile in-plane conduction and a hindered out-of-plane conduction. Pulsed field gradient nuclear magnetic resonance spectroscopy reveals a fast, simultaneous diffusion of a majority and a minority species for both 7Li and 1H, suggesting water-assisted lithium diffusion to be at play. This study enlarges the family of nanosheet-based ionic conductors and helps to rationalize the transport mechanism of lithium ions enabled by hydration in a nanoconfined 2D space.

Transfer of 1D Photonic Crystals via Spatially Resolved Hydrophobization.

1D photonic crystals (1DPCs) are well known from a variety of applications ranging from medical diagnostics to optical fibers and optoelectronics. However, large-scale application is still limited due to complex fabrication processes and bottlenecks in transferring 1DPCs to arbitrary substrates and pattern creation. These challenges were addressed by demonstrating the transfer of millimeter- to centimeter-scale 1DPC sensors comprised of alternating layers of H3 Sb3 P2 O14 nanosheets and TiO2 nanoparticles based on a non-invasive chemical approach. By depositing the 1DPC on a sacrificial layer of lithium tin sulfide nanosheets and hydrophobizing only the 1DPC by intercalation of n-octylamine via the vapor phase the 1DPC can be detached from the substrate by immersing the sample in water. Upon exfoliation of the hydrophilic sacrificial layer, the freestanding 1DPC remains at the water-air interface. In a second step, it can be transferred to arbitrary surfaces such as curved glass. In addition, the transfer of patterned 1DPCs is demonstrated by combining the sacrificial layer approach with area-resolved intercalation and etching. The fact that the sensing capability of the 1DPC is not impaired and can be modified after transfer renders this method a generic platform for the fabrication of photonic devices.

High Rate Transfer Mechanism of Lithium Ions in Lithium–Tin and Lithium–Indium Alloys for Lithium Batteries

The lithium–tin alloy electrode, as an artificial solid–electrolyte interphase (SEI) material with outstanding electrochemical properties, is promising to realize advanced next-generation lithium batteries. Experimental explorations on Li–Sn alloy have already achieved great success, while theoretical understanding on the mechanism of lithium-ion transport is still lacking. In this work, we carried out first-principles simulations and developed a theoretical methodology to reveal how a lithium ion diffuses in different lithium–tin phases and further elaborated the origin of low diffusion barriers. The simulation results indicate that two kinds of diffusion modes, interstitial and vacancy diffusion, will compete with each other with the increase in lithium concentration. Furthermore, the underlying mechanisms of direct hopping and coordinate process are also different in different Li–Sn/In phases. It is interesting to discover that during the lithiation process of alloy phases, the high-rate transport channel will gradually transform from the interstitial direct-hopping to vacancy mechanism and finally to the interstitial knock-off mechanism. This work provides a thorough theoretical understanding on lithium-ion transportation, further opening up the possibility of synthesizing or modifying SEI materials with enhanced Li conductivity in novel Li-ion battery designs.

Mechanical rolling formation of interpenetrated lithium metal/lithium tin alloy foil for ultrahigh-rate battery anode

To achieve good rate capability of lithium metal anodes for high-energy-density batteries, one fundamental challenge is the slow lithium diffusion at the interface. Here we report an interpenetrated, three-dimensional lithium metal/lithium tin alloy nanocomposite foil realized by a simple calendering and folding process of lithium and tin foils, and spontaneous alloying reactions. The strong affinity between the metallic lithium and lithium tin alloy as mixed electronic and ionic conducting networks, and their abundant interfaces enable ultrafast charger diffusion across the entire electrode. We demonstrate that a lithium/lithium tin alloy foil electrode sustains stable lithium stripping/plating under 30 mA cm−2 and 5 mAh cm−2 with a very low overpotential of 20 mV for 200 cycles in a commercial carbonate electrolyte. Cycled under 6 C (6.6 mA cm−2), a 1.0 mAh cm−2 LiNi0.6Co0.2Mn0.2O2 electrode maintains a substantial 74% of its capacity by pairing with such anode.

Effect of NASICON-type LiSnZr(PO4)3 ceramic filler on the ionic conductivity and electrochemical behavior of PVDF based composite electrolyte

Replacement of liquid electrolytes with polymer-based solid electrolytes is considered as the key to the realization of high-energy lithium metal anode in rechargeable batteries. However, the polymer electrolytes suffer from poor lithium-ion conductivity and low lithium-ion transference number. Poly(vinylidene difluoride) (PVDF) based polymer-ceramic composite electrolytes were fabricated at room temperature via the solution casting method. The effect of NASICON-type lithium tin zirconium phosphate (LiSnZr(PO4)3) particles added as the ceramic filler to the PVDF + LiTFSI polymer-salt matrix on the structure, ionic conductivity, transference number, and electrochemical behaviour was studied. The x-ray diffraction (XRD) and fourier transform infrared (FTIR) absorption studies confirmed the structure of the fabricated polymer as the mixed (α+β) phases of PVDF. The addition of LiSnZr(PO4)3 ceramic filler resulted in the enhancement in Li+ conductivity of the polymer composite and the sample with 15 wt% ceramic filler (CPE-15) showed the highest lithium-ion conductivity of 5.76 × 10−5 Scm−1 at 300 K. The addition of 15 wt% LSZP improved the stability window up to 4.73 V as confirmed by linear sweep voltammetry (LSV). A significant improvement in (tLi+) resulted from the addition of ceramic filler. The reversibility of Li+ transport across the composite ceramic-polymer electrolyte (15 wt% CPE) was confirmed by galvanostatic charging-discharging of symmetric lithium (Li||CPE||Li) cell at various current density for 100 h. Li||CPE||LTO cells with Li4Ti5O15 (LTO) as the working electrode, CPE-15 as the Li+ conducting separator, and Li foil as the counter electrode were fabricated to demonstrate the application of the CPE-15 as the electrolyte in all-solid-state batteries. Li||CPE||LTO cell delivered a specific discharge capacity of 133 mAhg−1 and 88% capacity retention after 20 cycles at 0.1C rate.

Pseudo catalytic ammonia synthesis by lithium–tin alloy

In this work, nitrogenation, ammonia generation, regeneration reactions of lithium-tin alloy is investigated as pseudo catalytic process of ammonia synthesis. Li17Sn4 synthesized by thermochemical method at 500 °C can react with 0.1 MPa of N2 below 400 °C. Nano or amorphous lithium nitride would be formed by the nitrogenation. By reaction of the nitrogenated samples and H2, ammonia is generated at 300 °C under 0.1 MPa. The initial alloy phase Li17Sn4 is regenerated below 350 °C from the products after the ammonia generation process. Based on the above three step process, ammonia can be pseudo-catalytically synthesized from N2 and H2 below 400 °C under ambient pressure. Furthermore, the reactivity for the ammonia synthesis using Li–Sn alloy is preserved during the NH3 synthesis cycles due to the characteristic reaction process based on the Li extraction and insertion.

Important Thermodynamic Parameters of Lithium–Tin Alloys from the Point of View of Their Use in Tokamaks

Along with other liquid metals, lithium–tin alloys are considered an alternative to the use of solid materials in the development of plasma-facing intrachamber components for future fusion reactors. The possibility of the practical use of these alloys in tokamaks is determined by their thermodynamic parameters, their ability to retain hydrogen isotopes in the melt, and the properties that determine the principles by which hydrogen isotopes can be extracted from a liquid Li–Sn alloy. The Sieverts’ constants for dilute hydrogen solutions in the melts of this system are calculated with the use of equations of the coordination-cluster model. The results of theoretical calculations are compared with previously published experimental data for two alloys of the Li–Sn system. A calculation method based on the use of the Butler equation, together with the experimentally obtained concentration dependences of the thermodynamic potentials of the components of this binary system, is applied to find the composition of the liquid-alloy surface.

Humidity Sensors: Lithium Tin Sulfide—a High‐Refractive‐Index 2D Material for Humidity‐Responsive Photonic Crystals (Adv. Funct. Mater. 14/2018)

In article number 1705740, Bettina V. Lotsch and co-workers report a new generation of photonic humidity sensors based on ultrahigh refractive index lithium tin sulfide nanosheets and antimony phosphate nanosheets. Both materials intercalate water and show pronounced swelling under the influence of humidity. Once integrated as ultrathin 1D photonic crystals, pronounced sensitivity to ambient humidity, along with excellent optical quality is achieved. Cover Design: Katalin Szendrei-Temesi.

Lithium Tin Sulfide—a High‐Refractive‐Index 2D Material for Humidity‐Responsive Photonic Crystals

AbstractExtending the portfolio of novel stimuli‐responsive, high‐refractive‐index (RI) materials besides titania is key to improve the optical quality and sensing performance of existing photonic devices. Herein, lithium tin sulfide (LTS) nanosheets are introduced as a novel solution processable ultrahigh RI material (n = 2.50), which can be casted into homogeneous thin films using wet‐chemical deposition methods. Owing to its 2D morphology, thin films of LTS nanosheets are able to swell in response to changes of relative humidity. Integration of LTS nanosheets into Bragg stacks (BSs) based on TiO2, SiO2, nanoparticles or H3Sb3P2O14 nanosheets affords multilayer systems with high optical quality at an extremely low device thickness of below 1 µm. Owing to the ultrahigh RI of LTS nanosheets and the high transparency of the thin films, BSs based on porous titania as the low‐RI material are realized for the first time, showing potential application in light‐managing devices. Moreover, the highest RI contrast ever realized in BSs based on SiO2 and LTS nanosheets is reported. Finally, exceptional swelling capability of an all‐nanosheet BS based on LTS and H3Sb3P2O14 nanosheets is demonstrated, which bodes well for a new generation of humidity sensors with extremely high sensitivity.

Hydrothermal synthesis of nano-SnO2@SiO2 composites for lithium-ion battery anodes

SnO2-based lithium-ion batteries have low cost and high energy density, but their capacity fades rapidly during lithiation/delithiation due to phase aggregation and cracking. A modified hydrothermal method was developed to synthesize tin oxide doped with highly dispersed silicon oxide, sing SnCl4·5H2O and amounts of tetraethyl orthosilicate as the starting materials and NH3·H2O as PH regulator. Fine powders of tin oxide as active materials were doped with highly dispersed silicon oxide as inert materials in atomic or nano-meter scale. The microstructure, morphology and electrochemical performance of the mixtures were analyzed by X-ray diffraction, infra-red, scanning electron microscopy and electrochemical methods. Silicon oxide as matrix should be able to support the anode changes accompanied by the formation of lithium–tin alloys, thus an improvement of the cycle ability of the Li-ion battery would be expected. The electrochemical results showed that addition of silicon oxide reduces the irreversible capacity during the first discharge/charge cycle. The electrochemical performance indicates that amorphous silicon oxide is an appropriate matrix and these composites are good anode candidates for application in lithium-ion batteries.

Overlapping and rate controlling electrochemical reactions for tin(IV) oxide electrodes in lithium-ion batteries

The results of this extensive electrochemical study of the electrochemical reactions of SnO2 electrodes in lithium-ion batteries demonstrate that the different reduction and oxidation reactions overlap significantly during the cycling and that the rates of the redox reactions are limited by the mass transport through the layers of oxidation or reduction products formed on the electrodes. The experiments, which were carried out in the absence and presence of the lithium alloy reactions, show that the capacity losses seen on the first cycles mainly can be explained by an incomplete oxidation of the lithium tin alloy and an incomplete reformation of SnO2. The latter can be explained by the formation of thin tin oxide layers (i.e., SnO and SnO2), protecting the remaining tin, as the oxidation current then becomes limited by the Li+ diffusion rate though these layers. The results, also show that the first cycle SnO2 reduction was incomplete for the about 20μm thick electrodes containing 1 to 6μm large SnO2 particles. This can be ascribed to the formation of a layer of tin and Li2O (protecting the remaining SnO2) during the reduction process. Although the regeneration of the SnO2 always was slower than the reduction of the SnO2, the results clearly show that the SnO2 conversion reaction is far from irreversible, particularly at low scan rates and increased temperatures. Electrochemical cycling at 60°C hence gave rise to increased capacities, but also a faster capacity loss, compared to at room temperature. These new findings indicate that a full utilization of SnO2 based electrodes at a given cycling rate only can be reached with sufficiently small particles since the allowed particle size is given by the time available for the mass transport through the formed surface layers. The present results consequently provide important insights into the phenomena limiting the use of SnO2 electrodes in lithium-ion batteries.

Nitrogen Dissociation via Reaction with Lithium Alloys.

Lithium alloys are synthesized by reactions between lithium metal and group 14 elements, such as carbon, silicon, germanium, and tin. The nitrogenation and denitrogenation properties are investigated by thermal and structural analyses. All alloys dissociate the nitrogen triple bond of gaseous molecules to form atomic state as nitrides below 500 °C, which is lower than those required for conventional thermochemical and catalytic processes on nitride syntheses. For all alloys except for germanium, it is indicated that nanosized lithium nitride is formed as the product. The denitrogenation (nitrogen desorption) reaction by lithium nitride and metals, which is an ideal opposite reaction of nitrogenation, occurs by heating up to 600 °C to form lithium alloys. Among them, the lithium–tin alloy is a potential material to control the dissociation and recombination of nitrogen below 500 °C by the reversible reaction with the largest amount of utilizable lithium in the alloy phase. The nitrogenation and denitrogenation reactions of the lithium alloys at lower temperature are realized by the high reactivity with nitrogen and mobility of lithium. The above reactions based on lithium alloys are adapted to the ammonia synthesis. As a result, ammonia can be synthesized below 500 °C under 0.5 MPa of pressure. Therefore, the reaction using lithium alloys is recognized as a pseudocatalyst for the ammonia synthesis.

Photoelectron Spectroscopic Evidence for Overlapping Redox Reactions for SnO2 Electrodes in Lithium-Ion Batteries

In-house and synchrotron-based photoelectron spectroscopy (XPS and HAXPES) evidence is presented for an overlap between the conversion and alloying reaction during the cycling of SnO2 electrodes in lithium-ion batteries (LIBs). This overlap resulted in an incomplete initial reduction of the SnO2 as well as the inability to regenerate the reduced SnO2 on the subsequent oxidative scan. The XPS and HAXPES results clearly show that the SnO2 conversion reaction overlaps with the formation of the lithium tin alloy and that the conversion reaction gives rise to the formation of a passivating Sn layer on the SnO2 particles. The latter layer renders the conversion reaction incomplete and enables lithium tin alloy to form on the surface of the particles still containing a core of SnO2. The results also show that the reoxidation of the lithium tin alloy is incomplete when the formation of tin oxide starts. It is proposed that the rates of the electrochemical reactions and hence the capacity of SnO2-based electrodes ...

Behavior of liquid Li-Sn alloy as plasma facing material on ISTTOK

The high power loads impinging on the first wall and particularly the divertor of fusion reactors is a decisive factor to the success of nuclear fusion. An alternative to solid plasma facing components is the use of liquid metals such as lithium or tin due to the regenerative properties of the liquid surface. Another suitable candidate is the eutectic lithium tin alloy (30at.% Li) which is suggested to display beneficial properties of both its constituent elements. The application of these materials as liquid metal plasma facing components depends on several factors such as their affinity to retain hydrogenic isotopes and the discharge performance degradation induced by the enhanced impurity contamination, among others. An experimental setup has been developed to produce and expose samples to ISTTOK plasmas on both liquid and solid states. Samples of Li-Sn alloy were exposed at ISTTOK to deuterium plasmas. Post-mortem analysis of the samples was performed by means of ion beam diagnostics. To quantify the fuel retention on the samples the nuclear reaction analysis (NRA) technique was applied. Complementary, Rutherford backscattering spectrometry (RBS) was used for determination material composition, particularly of impurities, on the samples. Regardless of the high sensitivity of these techniques no deuterium was detected in the samples. Emission of the Li-I 670.7nm line indicates that there was interaction of the plasma with the samples. Alternative reasons for the low retention of this material are discussed. Lithium segregation to the surface of the sample was observed.

Deuterium retention in tin (Sn) and lithium–tin (Li–Sn) samples exposed to ISTTOK plasmas

The use of lithium (Li) or tin (Sn) as a liquid metal plasma facing component is proposed as a solution to the high power load issue on the divertor region of nuclear fusion reactors. The possibility to use these materials depends on their compatibility with hydrogen plasmas. With the purpose of realizing deuterium retention studies, specimens of pure Sn (99.999% Sn) and Li–Sn alloy (30 at.% Li) were exposed in the ISTTOK edge plasma. Ex situ analysis of the samples was performed by means of ion beam diagnostics. Nuclear reaction analysis (NRA) technique was applied using the D(3He,p)4He reaction to quantify the fuel retention on the samples.In this work the deuterium retention is compared between pure Sn and Li–Sn alloy samples in both liquid and solid states. All the samples were found to have retention ratios smaller than 0.1 at.%. This low retention ratio is expected for pure tin given its high mass and the instability of tin hydrides. However the retention was unexpectedly low for the case of Li–Sn which was thought to be dominated by the lithium fraction in the alloy. These results suggest that tin has a role in the retention mechanism in this material.

Li0.6[Li0.2Sn0.8S2] – a layered lithium superionic conductor

Implementing vacant sites enhances the Li mobility in lithium tin sulfide enormously as demonstrated by the increase in Li conductivity from 10−5 S cm−1 in Li1.0[Li0.33Sn0.67S2] to 10−2 S cm−1 in Li0.6[Li0.2Sn0.8S2].