Lithium Ion Conductive Glass Research Articles

Three-chamber electrochemical reactor for selective lithium extraction from brine

Efficient lithium recovery from geothermal brines is crucial for the battery industry. Current electrochemical separation methods struggle with the simultaneous presence of Na+, K+, Mg2+, and Ca2+ because these cations are similar to Li+, making it challenging to separate effectively. We address these challenges with a three-chamber reactor featuring a polymer porous solid electrolyte in the middle layer. This design improves the transference number of Li+ (tLi+) by 2.1 times compared to the two-chamber reactor and also reduces the chlorine evolution reaction, a common side reaction in electrochemical lithium extraction, to only 6.4% in Faradaic Efficiency. Employing a lithium-ion conductive glass ceramic (LICGC) membrane, the reactor achieved high tLi+ of 97.5% in LiOH production from simulated brine, while the concentrations of Na+ K+, Mg2+, and Ca2+ are below the detection limit. Electrochemical experiments and surface analysis elucidated the cation transport mechanism, highlighting the impact of Na+ on Li+ migration at the LICGC interface.

Electrochemical Behavior of Tris(2,2'-bipyridine)Iron Complex in 1-Butyl-1-Methylpyrrolidinium Bis(fluorosulfonyl)Amide Ionic Liquid in the Presence and Absence of Lithium Ion

Ionic liquids composed of bis(fluorosulfonyl)amide (FSA–) have been investigated as the promising electrolytes for rechargeable batteries because of the formation of favorable solid electrolyte interphase (SEI) for some alkali metal ions in addition to relatively low viscosity. The FSA–-based ionic liquids are also considered to be applied to redox flow batteries, which utilize the electrode reactions of soluble species on inert electrodes. However, few electrode reactions of dissolved species have been explored in the FSA–-based ionic liquids. On the other hand, ion-conductive membranes are necessary for development of redox flow batteries. An inorganic solid-state conductor, lithium ion conductive glass ceramics (LICGC, Li1+x+y Al x (Ti,Ge)2-x Si y P3-y O12), is one of the possible membranes usable in ionic liquids containing Li+. In the present study, the electrochemical behavior of tris(2,2'-bipyridine)iron complexes, [Fe(bpy)3]2+, was investigated in BMPFSA (BMP = 1-butyl-1-methylpyrrolidinium) in the presence and absence of Li+.The redox reactions of [Fe(bpy)3]3+/2+, [Fe(bpy)3]2+/+, [Fe(bpy)3]+/0, and [Fe(bpy)3]0/– were observed by cyclic voltammetry in the absence of Li+. However, these reactions were affected by the SEI formation at a negative potential region in the presence of Li+. The donor number of BMPFSA was estimated from the formal potential of [Fe(bpy)3]3+/2+. The diffusion coefficients of [Fe(bpy)3]3+ and [Fe(bpy)3]2+ were determined by chronoamperometry. The standard rate constant for [Fe(bpy)3]3+/2+ was evaluated by electrochemical impedance spectroscopy. The relationship between these kinetic parameters and physical properties was discussed.

Hydrogen Absorption in Near Surface of Lithium-ion Conductive Glass Ceramics by Water Uptake at Room Temperature

The hydrogen isotope (H and D) concentrations in the two types of Li1+xAlxTi1−x/2Ge1−x/2P3−yO12 and Li1+x+yAlxTi2−xSiyP3−yO12 (LATP: AG-01 and SP-01, respectively) electrolytes, soaked in D2O for 19—22 days and subsequently exposed to air at room temperature and humidity of 80% for 11—21 days, were measured by combining elastic recoil detection with Rutherford backscattering spectrometry. The total numbers of H and D atoms in AG-01 and SP-01 were estimated to be approximately 5.0 and 0.66 atoms, respectively, after the absorption of H2O and D2O and the replacement of H by D. Field emission scanning electron microscopy and atomic force microscopy images revealed that many black substance formations with dimensions of approximately 0.5 × 3.0 μm2 in area and less than approximately 200 nm in thickness appeared on the surface of the D2O-soaked and air-exposed AG-01. These formations appeared because of the segregation of Li from the bulk to the surface by the reactions of H2O and D2O with the doped Ge, which might lead to H and D trapping at the Li substitutional sites.

Influence of Inorganic Glass Ceramic Particles on Ion States and Ion Transport in Composite Single-Ion Conducting Gel Polymer Electrolytes with Varying Chain Chemistry

A major goal of next-generation battery development is the engineering of nonflammable solid-state electrolytes with high enough ionic conductivity to compete with traditional liquid electrolytes. Composite polymer electrolytes (CPEs), which combine inorganic fillers or electrolytes with a polymer matrix, are seen as a strategy to boost the ionic conductivity of flexible polymer electrolytes while overcoming the brittle aspect of inorganic electrolytes. In this work, we examine the impact of polymer backbone chemistry on Li+ ion conduction within crosslinked single-ion conducting gel polymer electrolytes (SIPEs) that contain a lithium ion-conducting glass ceramic electrolyte (LICGC). Certain SIPE compositions based on poly(tetrahydrofuran) diacrylate (PTHFDA) crosslinking macromonomers exhibit a significant increase in conductivity with the inclusion of LICGC, a result unexpected from prior literature. With the use of Raman spectroscopy, small angle X-ray scattering, and particle-induced gamma-emission spectroscopy (PIGE), it is proposed that the enhanced conductivity comes from the formation of percolated LICGC particles sheathed in an ion-rich domain. This region develops in the pre-polymer solution due to interactions between the LICGC particle surface and the ionic comonomer, much like the formation of space-charge regions in soggy-sand liquid electrolytes, and persists post-polymerization to yield a CPE of enhanced conductivity. The particle–ionic monomer interactions are modulated by the crosslinking macromonomer polarity, polymer casting solvent, and particle surface area. While there is ample room for continued optimization, the best SIPEs in this study are capable of Li metal dissolution/deposition, and they reach Li+ conductivities greater than 2 × 10–4 S/cm at 25 °C, surpassing the practical use threshold.

Low-Temperature Densification of Nasicon-Type Electrolyte for Bulk-Type All-Solid-State Battery

Submicron particles of Na SuperIonic CONductor (NASICON)-type Li2O-Al2O3-TiO2-P2O5 (LATP) are possible to be densified at low temperature of 300 ºC by applying high pressure of 600 MPa during spark-plasma sintering (SPS) process. This process provides a novel route for assembling bulk-type all-solid-state lithium-ion battery (ASS-LIB), which promises high safety and high durability of energy storages since the origins of flammability and undesirable electrochemical events are prevented by using oxide as an electrolyte instead of the non-aqueous liquid.The main challenge for assembling bulk-type ASS-LIB are how to reduce the sintering temperature of the oxide electrolyte since most of the electrode materials decompose readily at high temperatures. Previously, we have attempted to design LiCoO2-electrode/NASICON-type LiTi2(PO4)3-electrolyte interface by conventional SPS process since quick/low-temperature treatment by the SPS has a possibility for reducing the decomposition kinetically.1 However, the several-μm ion-blocking interphase was easily-produced at the interface. Therefore, further low-temperature technique is required for the design of impurity-free electrode/electrolyte heterointerfaces. Commonly, the low-temperature sinterability of ceramic (or metal) particles could be accomplished with the increase of the contact for active surfaces by reducing particle size and/or applying higher pressure under sintering. Kinemuchi et al. has suggested that the low-temperature densification (LTD) of the oxide was performed by combining the use of nano particles and external pressure of over several-hundred MPa during the SPS.2 The LTDs for lithium-ion conductive oxides have possibilities for producing impurity-free electrode/electrolyte interface, and therefore would be one of the promising techniques for assembling oxide-based bulk-type ASS-LIB.In the present study, we used submicron size of NASICON-type Li2O-Al2O3-TiO2-P2O5 (LATP) powder as high bulk lithium-ion conductive oxides, which have been developed as Lithium Ion Conductive Glass Ceramics; LICGCTM, by OHARA INC..3,4 The densification of the LATP powder compact could be certified at low temperature of 200 - 250 °C under applying a pressure of 600 MPa during the SPS. Generally, the LTDs for oxides were achieved using not submicron particles but nano particles. However, the LTDs of the submicron-size particles could be confirmed in a phosphate group, which includes Li3PO4, AlPO4, and also LATP. Therefore, the bulk-type ASS-LIBs with phosphate-based electrodes such as LiFePO4 and Li2CoPO4F were successfully assembled by the LTD processes because the undesirable-thermal impurities at electrode/electrolyte interface were prevented during the low-temperature treatment. The characterization of LiFePO4/LATP interface and the electrochemical performance of ASS-LIB cell (Li/dry polymer/LATP/LiFePO4) will be presented in the conference.

Effect of Electrode Overpotential in Secondary Solution on Lithium Recovery Rate for Electrodialysis with Two Power Supplies and Three Electrodes

Demand for lithium-ion batteries (LIB) is rapidly increasing with the electrification of automobiles and the spread of new energy management systems. It is desired to recover lithium resources, whose supply and demand are tight, from spent LIB and seawater. Lithium for LIB must have a high purity of 99.9% or higher. The electrodialysis method using a lithium ion electrolyte has a high potential for recovering such high-purity lithium. Kunugi et al. [1] reported that only lithium ions could be recovered from LiCl-NaCl-KCl mixed aqueous solution by electrodialysis using La0.55Li0.35TiO3 as an electrolyte. Hoshino [2] demonstrated the possibility of using lithium ion conductive glass ceramics (LICGCTM). However, in either method, the lithium recovery rate is too low for practical use. We have devised an electrodialysis system with two power sources and three electrodes, which is different from a general electrodialysis cell consisting of two electrodes and one power source, and experimentally confirmed a large lithium recovery rate. In this study, we investigate the effect of electrode overvoltage in the secondary solution on the lithium recovery rate by this new electrodialysis method. An anode (primary solution side) and a cathode (secondary solution side) were formed on both sides of the La0.57Li0.29TiO3 (LLTO) by firing a Pt paste. As a third electrode, a Ni mesh electrode was placed in the secondary solution at a position apart from the cathode. A constant DC voltage was applied between the anode and the cathode. A constant DC voltage of another magnitude was also applied between the cathode and the Ni mesh electrode. The electric resistance of the solution between the cathode and the third electrode was changed by changing the lithium concentration in the secondary side solution or the distance between the cathode and the third electrode. The change in the lithium recovery rate due to this change in electrical resistance was investigated. The recovery rate was calculated using the lithium concentration in the secondary side solution measured by inductively coupled plasma optical emission spectroscopy. The electrical resistance of the solution between the cathode and the third electrode decreased due to the increase of the lithium-ion concentration in the secondary side solution, and the overpotential for the electrochemical reaction on the cathode and the third electrode increased. As a result, the lithium recovery rate was increased.[1] S. Kunugi, Y. Inaguma and M. Itoh, Solid State Ionics, 122, 35-39 (1999).[2] T. Hoshino, Desalination, 359, 59-63 (2015).

Local electrical degradations of solid-state electrolyte by nm-scale operando imaging of ionic and electronic transports

We report on degradation mechanisms of solid-state electrolyte (SSE) based on insights from nm-scale ionic conduction and electronic leakage for solid-state batteries. The significantly different local degradations revealed by nm-scale ionic and electronic transport imaging demonstrate the need for this nm-scale investigation. State-of-the-art lithium-ion conductive glass ceramic (Li2O–Al2O3–SiO2–P2O5–TiO2-GeO2) SSE shows at least two types of degradations spatially separated within the SSE, namely: (1) ionic conduction blocking and slight electronic leaking and (2) highly electronic shunting. Degradation was significantly suppressed by application of a Li-containing polyacrylonitrile thin coating on both sides of the ceramic SSE. With this coating, the ionic conduction was not reduced by the extensive cycling; instead, it improved slightly, although accompanied by a slight increase in electronic leaking. Our nm-scale transport imaging was achieved using an atomic force microscopy (AFM)-based half-cell setup and a logarithmic-scale amplifier with current sensitivity down to the fA (10−15 A) range. This half-cell setup consisting of an AFM-probe/SSE/Li structure can distinguish the ionic from the electronic current by flipping the bias-voltage polarity. This nm-scale operando imaging opens up novel characterization of ionic and electronic transport in the field of solid-state batteries.

An ambipolar transistor based on a monolayer WS2 using lithium ions injection

Ambipolar field-effect transistor (FET) devices based on two-dimensional (2D) materials have been attracted much attention due to potential applications in integrated circuits, flexible electronics and optical sensors. However, it is difficult to tune Fermi level between conduction and valence bands using a traditional SiO2 as dielectric layer. Here, we employed the lithium-ion conductive glass ceramic (LICGC) as the back-gate electrode in a monolayer WS2 FET. The effective accumulation and dissipation of Li+ ions in the interface induce a wide tune of Fermi level in the conducting channel by electron and hole doping, which show an ambipolar transport characteristics with threshold voltages at 0.9 V and −1.3 V, respectively. Our results provide an opportunity for fabricating ultra-thin ambipolar FET based on 2D materials.

Nanoscale Mapping of Extrinsic Interfaces in Hybrid Solid Electrolytes

Summary Inorganic-organic hybrid solid electrolytes are promising material systems for all solid-state batteries (ASSBs). These electrolytes contain numerous solid | solid interfaces that govern transport pathways, electrode | electrolyte compatibility, and durability. This paper evaluates the role that electrode | electrolyte interfaces and electrolyte structure have on electrochemical performance. Atomic force microscopy techniques reveal how mechanical, adhesion, and morphological properties transform in a series of model hybrid solid electrolytes. These measurements are mapped to sub-surface microstructural features using synchrotron nano-tomography. Hybrid solid electrolytes with shorter polymer chains demonstrate a higher adhesion ( > 100 nN), Young's Modulus (6.4 GPa), capacity (114.6 mAh/g), and capacity retention (92.9%) than hybrid electrolytes with longer polymer chains (i.e., higher molecular weight). Extrinsic interfacial properties largely dictate electrochemical performance in ASSBs. Microstructural control over inorganic constituents may provide a means for tailoring interfacial properties in hybrid solid electrolytes.

Preparation and characterization of lithium ion conductive Li3SbS4 glass and glass-ceramic electrolytes

Li3SbS4 glass was prepared by a mechanochemical process and a glass-ceramic was prepared by heating the glass above the crystallization temperature. The glass-ceramic had a crystal structure similar to that of γ-Li3PS4. As indicated by the Raman spectra, both electrolytes contained an SbS4 unit. The conductivity of the pelletized Li3SbS4 glass was 1.5 × 10−6 S·cm−1 at 25 °C, which was higher than that of its glass-ceramic. The amount of H2S generated from Li3SbS4 glass in humid air was considerably lower than that from the Li3PS4 glass.

Electrochemical Synthesis of Ammonia from Water and Nitrogen: A Lithium-Mediated Approach Using Lithium-Ion Conducting Glass Ceramics.

Lithium-mediated reduction of dinitrogen is a promising method to evade electron-stealing hydrogen evolution, a critical challenge which limits faradaic efficiency (FE) and thus hinders the success of traditional protic-solvent-based ammonia electro-synthesis. A viable implementation of the lithium-mediated pathway using lithium-ion conducting glass ceramics involves i) lithium deposition, ii) nitridation, and iii) ammonia formation. Ammonia was successfully synthesized from molecular nitrogen and water, yielding a maximum FE of 52.3 %. With an ammonia synthesis rate comparable to previously reported approaches, the fairly high FE demonstrates the possibility of using this nitrogen fixation strategy as a substitute for firmly established, yet exceedingly complicated and expensive technology, and in so doing represents a next-generation energy storage system.

Electromotive force measurements of LiCoO2 electrode on a lithium ion-conducting glass ceramics under mechanical stress

Two LiCoO2 dense film electrodes were prepared on both surfaces of a lithium ion-conducting glass ceramics, and electromotive force measurements were preformed between the film electrodes under mechanical compressive and tensile stresses by four-point bending tests. Electromotive force appeared immediately after applying the stress and disappeared after releasing the stress. The larger stress was applied, the larger electromotive force was observed. These results clearly demonstrated that the lithium chemical potential in the LiCoO2 electrode varies under mechanical stress. The influence of the mechanical stress on the lithium chemical potential was discussed based on the relation between the CoO2 interlayer distance and the lithium concentration in LiCoO2.

Invited Presentation: Lithium Dendrite Formation at the Interface Between Lithium Metal and PEO Complexed with Various Lithium Salts

Protected Lithium Electrode for Aqueous Lithium-Air Rechargeable BatteriesNobuyuki Imanishi Department of Chemistry, Mie University, Tsu , Japan The novelty of aqueous lithium air battery is the introduction of a protected lithium electrode using an impermeable lithium ion-conducting glass ceramics, Li1+x+y(Ti,Ge)1-xAlxP3-ySiyO12 (LTAP), which enables lithium metal anode feasible in the aqueous electrolyte with a narrow electrochemical window and boosts the specific energy density of this system coupling with a breathing air cathode [1]. The inherent drawback of LTAP is the high reduction tendency of its constituent, Ti4+ or Ge4+, in contact with lithium metal, which results in the generation of insulated reaction products. Several lithium-ion conducting interlayers have been proposed to address this issue, such as lithium nitride, lithium phosphorus oxynitride, polymer electrolytes as well as accustomed organic electrolytes. The two former materials are generally prepared by vapor deposition, which involves considerable cost and makes the preparation of large-sized cells difficult. In contrast, large-sized sheets of polymer electrolytes can be easily fabricated along with little concerns over lithium dendrites formation unlike the case for organic electrolytes.Protected lithium electrodes consisting of lithium metal anode, polymer electrolytes-based interlayers and LTAP are our proposed solution for the practical development of aqueous lithium air battery. However, two contradictory issues emerge; those are the lithium dendrite formation at the interface between lithium metal and polymer electrolyte interlayers and the rate capability of protected lithium electrodes.In our previous studies, the interfacial resistance between lithium metal and polymer electrolytes has been demonstrated a key factor in initiating lithium dendrite formation by addition of ionic liquids, oligomer ethers and/or nanofillers. All these additives can reduce the interfacial resistance substantially and prolong the onset time of lithium dendrite initiation. A prospective additive of tetraethylene glycol dimethyl ether was revealed to exhibit the onset time of ca. 13 h for protected lithium electrodes at 1.0 mA·cm-2. The anion of lithium salts complexed with polymer matrix was also identified to influence the dendrite initiation in our recent study, where bis (fluorosulfonyl) imide-FSI- exhibited the longest short-circuit time of symmetrical lithium pouch cell compared to other larger analogues.At high current densities, the onset time of lithium dendrite initiation is shortened and thus the capacity of protected lithium electrode that can deliver is limited. A protected lithium electrode capable of delivering a high areal capacity of 12 mAh·cm-2 or more at no less than 1.0 mA·cm-2 is critical to develop aqueous lithium air batteries for electric vehicle applications. However, the binary polymer electrolytes we are developing usually exhibit a low limiting diffusion current density and are prone to initiate lithium dendrite formation when the operating current density exceeds its inherent limiting diffusion current density due to the quick depletion of lithium cations and the accompanying instability of interface. Moreover, the low exchange current density for polymer electrolytes at the interface also limits the rate capability of protected lithium electrodes.Based on our previous findings, we are now envisaging a new concept for the lithium-ion conducting interlayer, such as solvent-in-salt systems and single-ion polymer electrolytes, to diminish the trade-off between the two aforementioned issues for protected lithium electrodes in the development of aqueous lithium air battery.[1] N. Imanishi and O. Yamamoto, Rechargeable lithium–air batteries: characteristics and prospects, Mater. Today, 17, 24 (2014).

Interface Properties between Lithium Metal and a Composite Polymer Electrolyte of PEO18Li(CF3SO2)2N-Tetraethylene Glycol Dimethyl Ether.

The electrochemical properties of a composite solid polymer electrolyte, consisting of poly(ethylene oxide) (PEO)-lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and tetraethylene glycol dimethyl ether (TEGDME) was examined as a protective layer between lithium metal and a water-stable lithium ion-conducting glass ceramic of Li1+x+y(Ti,Ge)2−xAlxP3−ySiyO12 (LTAP). The lithium ion conductivity and salt diffusion coefficient of PEO18LiTFSI were dramatically enhanced by the addition of TEGDME. The water-stable lithium electrode with PEO18LiTFSI-2TEGDME, as the protective layer, exhibited a low and stable electrode resistance of 85 Ω·cm2 at 60 °C, after 28 days, and low overpotentials of 0.3 V for lithium plating and 0.4 V for lithium stripping at 4.0 mA·cm−2 and 60 °C. A Li/PEO18LiTFSI-2TEGDME/LTAP/saturated LiCl aqueous solution/Pt, air cell showed excellent cyclability up to 100 cycles at 2.0 mAh·cm−2.

A Composite Polymer Electrolyte Protect Layer between Lithium and Water Stable Ceramics for Aqueous Lithium-Air Batteries

The electrochemical properties of a composite polymer electrolyte consisting of polyethylene oxide (PEO)-lithium trifluoromethanesulfonylimide (LiTFSI) and poly(ethylene glycol) dimethyl ether (PEGDME) were examined as a protective layer between a lithium metal electrode and water-stable lithium ion-conducting glass ceramic of Li1.35Ti1.75Al0.25P0.9Si0.1O12. The lithium ion transport number was doubled and the lithium ion conductivity was enhanced from 1.3 × 10−4 for PEO18LiTFSI to 3.8 × 10−4 S cm−1 at 60°C by the addition of 18 wt% PEGDME. The lithium stripping and plating over-potentials for the Li/PEO18LiTFSI-18 wt% PEGDME/LTAP/1M LiCl aqueous solution/Pt, air cell were 0.3 and 0.25 V at 1.5 mA cm−2 and 60°C, respectively. Steady charge and discharge potentials for the Li/PEO18LiTFSI-18 wt% PEGDME/LTAP/10 M LiCl-4 mM LiOH/Pt air cell were observed for 12 h at 1.0 mA cm−2 and 60°C without short circuiting of the cell. Lithium dendrite formation at the lithium/PEO18LiTFSI interface was suppressed by the addition of PEGDME.

Grain Boundaries in a Lithium Aluminum Titanium Phosphate-Type Fast Lithium Ion Conducting Glass Ceramic: Microstructure and Nonlinear Ion Transport Properties

The structure and lithium ion transport properties of grain boundaries in the Ohara lithium-ion conductive glass ceramic (LI-CGC) were studied by means of nonlinear impedance spectroscopy and high-resolution transmission electron microscopy (HR-TEM). Ac voltages up to 0.8 V (rms) per single boundary could be applied without any irreversible changes of the lithium ion transport properties. Although the activation energy of the grain boundary resistance is only 30 meV higher than the activation energy of the grain resistance, large ac voltages >500 mV per single grain boundary were needed for reducing the grain boundary resistance to a level similar to the grain resistance. Consequently, we argue that the higher activation energy of the grain boundary resistance is not caused by a single barrier (e.g., a single space charge barrier), but by a number of serial barriers. By comparing the nonlinear grain boundary conductivity of the LI-CGC with that of other thin ion conducting layers, we estimate an average e...

Partially Reversible Electrochemistry on the Surface of Lithium-Ion Conducting Glass Ceramic by Electrochemical Strain Microscopy

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Nanoscale electrochemical measurements on a lithium-ion conducting glass ceramic: In-situ monitoring of the lithium particle growth

We performed nanoscopic cyclic voltammetry and chronoamperometry on the Ohara lithium ion conductive glass ceramic. When the critical bias voltage was exceeded, metallic lithium particles were deposited irreversibly under the conductive AFM tip acting as working electrode. Due to the huge area difference between working electrode and counter electrode, a reference electrode was not required. We present an in-situ method for studying the particle growth mechanism by simultaneously monitoring the reduction current and the particle height. We found good agreement between the topographically determined volume of the lithium particles and the volume expected from the charge flow. The results for time dependence of the particle growth can be used for controlling the vertical and lateral dimensions of the particles.

Irreversible Conduction of Lithium-Ions in Lithium-Ion Conducting Glass Ceramic on the Nanoscale by Electrochemical Strain Microscopy

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Lithium/Water Battery Using Lithium-Ion Conducting Glass Ceramics

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