Use In Solid-state Batteries Research Articles

Diagnostic of Solid-State Lithium Metal Batteries with the Sand Equation: A Symmetric Cell Electrochemical Characterization Method upon Plating

Lithium Metal Anodes (LMAs) have generated significant interest for use in solid-state batteries (SSBs) due to their high theoretical specific capacity. Nonetheless, issues such as dendrite growth (1) and cell failure caused by lithium loss with solid polymer electrolytes (SPEs) (2) of decent ionic conductivities have hindered widespread commercialization. In this work, we report the electrochemical characterization of symmetric Li- SPE– Li cells using thermoplastic vulcanizate (TPV) electrolytes comprised of: PCL:HNBR LiTFSI. Full plating of the lithium metal (LiM) electrode was achieved at 100 μA.cm-2 during constant polarization in pressurized pouch cells. Complete polarization was confirmed through ex-situ analysis by scanning electron microscopy (SEM) with SEM images showing that no dendrites were formed at this current density. Furthermore, cell polarization performed at higher current densities allowed lithium diffusion in the TPV electrolyte to be calculated using the Sand Equation (3, 4). Lithium diffusion was found to be 1.7 x 10-8 cm2.s-1 at 60 °C, which was consistent with other published values (5). The calculated threshold current density (j*) of the corresponding symmetric Li cell was approximately 200 μA.cm-2, confirming the cell failures due to dendrite growth and short circuiting that were observed in the system above this current density. This j* provides valuable information regarding the design of a full cell as the operation current density would be driven by the Li-SPE interface limitation. To this end, 100 cycles were performed in Li-Li symmetric cells with the TPV electrolyte without failure at currents below j* with 0.1 mAh.cm-2 of charge being transferred per cycle, while a charge of 0.5 mAh.cm-2 resulted in rapid cell failure. These findings emphasize the need for current densities and charge references in symmetric Li-Li cells and cells employing solid electrolytes. C. Monroe, J. Newman, The Impact of Elastic Deformation on Deposition Kinetics at Lithium/Polymer Interfaces. Journal of The Electrochemical Society 152, A396 (2005).L. Caradant et al., Effect of Li+ Affinity on Ionic Conductivities in Melt-Blended Nitrile Rubber/Polyether. ACS Applied Polymer Materials 2, 4943-4951 (2020).L. Stolz, G. Homann, M. Winter, J. Kasnatscheew, The Sand equation and its enormous practical relevance for solid-state lithium metal batteries. Materials Today 44, 9-14 (2021).D. Devaux et al., Effect of Electrode and Electrolyte Thicknesses on All-Solid-State Battery Performance Analyzed With the Sand Equation. Frontiers in Energy Research 7, (2020).T. Meyer, T. Gutel, H. Manzanarez, M. Bardet, E. De Vito, Lithium Self-Diffusion in a Polymer Electrolyte for Solid-State Batteries: ToF-SIMS/ssNMR Correlative Characterization and Modeling Based on Lithium Isotopic Labeling. ACS Applied Materials & Interfaces 15, 44268-44279 (2023).

Microwave-Assisted Synthesis of Argyrodite Solid Electrolytes and Their Use in Solid-State Batteries

Microwave-Assisted Synthesis of Argyrodite Solid Electrolytes and Their Use in Solid-State Batteries

Tailoring Silicon Composite Anodes with Li+-Containing Organic Ionic Plastic Crystals for Solid-State Batteries

Silicon is one of the highest-capacity anode active materials and, therefore, its use in solid-state batteries (SSBs) is expected to provide both high energy density and safety. Although the creation of solid-state Si electrodes via a scalable method is important from the perspective of battery production, the effect of electrode-preparation methods on electrochemical performance of electrodes with Li+-containing organic ionic plastic crystals (OIPCs) as solid electrolytes has yet to be investigated. Here, we prepared various Si−OIPC composite electrodes using four different methods and measured their electrochemical performance to decipher the method−structure−property relationship for high-performing SSBs. Si−OIPC composite electrodes containing 50 mol% LiFSI in N-ethyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide ([C2mpyr][FSI]) showed the highest initial Coulombic efficiency and cyclability. Three out of the four methods provided the Si−Li0.50[C2mpyr]0.50[FSI] electrodes with relatively large capacity retentions that were close to that of the Si electrode in a liquid electrolyte solution. Elemental analysis of electrode cross-sections showed homogeneous distribution of Li0.50[C2mpyr]0.50[FSI], except for those prepared by the drop-cast method, suggesting that well-designed methods can establish the long-range ion-conduction network in the electrode necessary to improve the electrochemical stability of Si during cycling. This study clarifies the importance of the OIPC-incorporation method in fabricating highly functional OIPC-based electrodes for SSBs.

Impact of Short Chain Polymer in Ionic Conductivity for Polymer Solid-State Electrolyte Towards Inter-/Intramolecular O-H Bond

Poly(ethylene oxide) (PEO) was first developed as a conducting polymer over a half-century ago and is still the most fascinating electrolyte matrix to use in solid-state batteries. Although thousands of articles have been published on the conductivity of various PEO-based solid-state electrolytes, none of the studies involved a higher EO-to-salt ratio up to 85 to 1. In this study, solid polymer electrolytes (SPE) based on the PEO-PEG complex with Sodium(I) Bis(trifluoromethanesulfonyl)imide (NATFSI) were prepared using the solid-state synthesis methods. The measurement using the Electrochemical Impedance Spectroscopy (EIS) technique demonstrated that EO70Na - 9PEO:3PEG has the most optimum PEO-PEG-NATFSI electrolyte system with conductivities of 0.01 mS/cm and 0.13 mS/cm at 25 °C and 50 °C, respectively. As reported in published articles, the conductivity of the EO to Na ratio started to decline from 15:1 to 25:1 with the dropped in NATFSI concentration. Further decline of Na concentration with the addition of EO from 40 to 70 ratio indicates a new increasing trend for the conductivity series, which result in a bimodal graph distribution. Fourier transform infrared (FTIR) spectral studies for PEO-PEG-based SPE revealed that vibrational changes of intramolecular -OH change as the concentration of short-chain polymer backbone and salt varies. The Raman spectral studies for PEO-PEG-based SPE proposed that the percentage of bis(trifluoromethane)sulfonimide anion (TFSI- anions) increases with the increase in ratio from 15 to 70 of EO to Na. It is proposed that a higher percentage of both intramolecular -OH and TFSI- anions are crucial in providing high conductivity value. The structure of complexed PEO-PEG-based SPE from XRD suggested that the crystalline domain of SPE decreased with the smaller amount of NATFSI.

Enhancing Fast-Charge Capabilities in Solid-State Lithium Batteries through the Integration of High Li0.5La0.5TiO3 (LLTO) Content in the Lithium-Metal Anode.

Solid-state batteries (SSBs), which have high energy density and are safe, are recognized as an important field of study. However, the poor interfacial contact with high resistance, the dendrite problem, and the volume change of the metallic lithium anode prevent the use of SSBs. Li0.5La0.5TiO3 (LLTO) particles and molten lithium were used to create a high-performance LLTO-Li composite lithium with a sequential ion-conducting phase. With garnet electrolytes, this lithium has better wettability and reduced surface tension. To compensate for the lithium depletion that occurs during stripping, the Li-Ti phase with a high ionic diffusion coefficient that forms in the anode can rapidly transport lithium from the bulk to the solid-state interface, ensuring tight interface contact, preventing the formation of gaps, and homogenizing the current and Li+ flux. The LLTO-Li| LLZTO| LLTO-Li symmetric cell exhibits a good cyclic stability of 1000 h at room temperature, a low interfacial resistance of 22 Ω cm2, and a high critical current density of 1.2 mA cm-2. Furthermore, fully built cells with a LiFePO4 cathode showed outstanding cycling performance, maintaining 95% of their capacity after 900 cycles at 1 C and 92% capacity retention after 100 cycles at 2 C.

High-Modulus Single-Ion-Conducting Electrolytes Based on a Rigid-Rod Polyanion

Single-ion-conducting electrolytes enable easy processing and can block Li dendritic growth, showing potential for use in solid-state batteries. We report solid electrolytes that combine a rigid-rod polyanion, poly(2,2′-disulfonyl-4,4′-benzidine terephthalamide) (PBDT), with Na+ or Li+ counterions, and poly(ethylene glycol) (PEG, Mn = 400 g mol–1). PBDT-PEG membranes show Young’s modulus from 90 to 2110 MPa that increases with the PBDT content and is >4× higher for Li-based vs Na-based electrolytes. We attribute this dramatically higher modulus in LiPBDT–PEG to poorer ion dissociation between Li+ and PBDT sulfonate groups and stronger interactions between LiPBDT and PEG. These membranes show an increase in ionic conductivity with increasing PEG concentration (0.1–7 μS cm–1 at 30 °C), reaching 0.13 mS cm–1 at 120 °C. These materials use highly rigid and charged PBDT double helices to “solidify” low-molecular-weight PEG into mechanically strong and highly single-ion-conductive solid polymer electrolytes with high thermal stability. Their combination of high cation conductivity and high modulus exceeds those of competing single-ion conductors at 30 °C.

In Situ Polymerization of Fluorinated Polyacrylate Copolymer Solid Electrolytes for High-Voltage Lithium Metal Batteries at Room Temperature

Poly(ethylene oxide) is a promising solid polymer electrolyte (SPE) matrix. However, its low ionic conductivity, narrow electrochemical window, and sluggish interfacial charge transfer limit its use in solid-state batteries at room temperature. Herein, we report the in situ polymerization of poly(2,2,3,4,4,4-hexafluorobutyl acrylate-copolymer-2-(2-(2-methoxyethoxy) ethoxy)ethyl acrylate) (P(HFBA-co-MEA)) with lithium bis(trifluoromethane sulfonamide) (LiTFSI) to form a fluorinated SPE (P(HFBA-co-MEA)/LiTFSI). When the molar ratio of HFBA to MEA is 1:1, P(HFBA1:1-co-MEA) exhibits a lower lithium-ion absorption energy (−4.602 eV) than that of PMEA (−4.372 eV), providing a fast transport pathway for lithium ions. The electron-absorbing properties of the −C–F group can reduce the lone-pair electron density around the ether-oxygen group and increase the electrochemical window of P(HFBA1:1-co-MEA)/LiTFSI to 4.9 V. In addition, P(HFBA1:1-co-MEA)/LiTFSI demonstrates excellent compatibility with lithium anodes, and the Li|P(HFBA1:1-co-MEA)/LiTFSI|LiNi0.5Co0.3Mn0.2O2 battery has a capacity retention of 62.3% after 170 charge–discharge cycles at 0.1C.

Electrochemical Characterization of a Drawn Thin-Film Glassy Oxide Electrolyte Material for Solid-State Battery Applications

Solid-state batteries present many advantages over liquid electrolyte systems, enabling the use of lithium metal anodes due to the non-flammable nature of the inorganic electrolyte. Glassy materials in particular are promising candidates as solid electrolytes due to their highly tunable properties, the absence of grain boundaries, and their ease of processability. The large compositional window of glassy materials allows for optimizing glass-forming ability and conductivity, while the lack of grain boundaries may be beneficial in preventing lithium dendrite formation. While lithium metaphosphate (LiPO3) has a low room temperature ionic conductivity (σ25°C = 1.6 ∙ 10-9 S/cm) that limits its use in solid-state batteries, oxides present similar processability and higher chemical and electrochemical stability than their higher conductivity sulfide analogues. LiPO3 was chosen for a preliminary investigation into the effects and challenges of decreasing electrolyte thickness due to its low processing temperature and ease of fabrication. The electrochemical behavior of drawn thin-film LiPO3 was studied through electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and galvanostatic symmetric cell cycling. These results show that with higher conducting oxy-sulfide glassy electrolyte materials, drawn thin-film electrolytes are a viable and valuable research direction.

Preparation and Structure of the Ion-Conducting Mixed Molecular Glass Ga2I3.17

Modern functional glasses have been prepared from a wide range of precursors, combining the benefits of their isotropic disordered structures with the innate functional behavior of their atomic or molecular building blocks. The enhanced ionic conductivity of glasses compared to their crystalline counterparts has attracted considerable interest for their use in solid-state batteries. In this study, we have prepared the mixed molecular glass Ga2I3.17 and investigated the correlations between the local structure, thermal properties, and ionic conductivity. The novel glass displays a glass transition at 60 °C, and its molecular make-up consists of GaI4– tetrahedra, Ga2I62– heteroethane ions, and Ga+ cations. Neutron diffraction was employed to characterize the local structure and coordination geometries within the glass. Raman spectroscopy revealed a strongly localized nonmolecular mode in glassy Ga2I3.17, coinciding with the observation of two relaxation mechanisms below Tg in the AC admittance spectra.

Аккумуляторные батареи. Твердотельные аккумуляторные батареи электромобиля

Most electric vehicles have a range of less than 300 miles, take more than an hour to recharge the battery, lose almost one-third of their cell capacity over 10 years, and pose a serious safety risk when handling flammable materials, resulting in an explosion. This article discusses the various types of electric car batteries, their operation, advantages and disadvantages. Solid-state batteries – the battery technology of the future, one of the most active areas of research of secondary batteries. The scientific community believes that lithium-ion batteries have reached their limit, solid-state batteries in recent years are seen as batteries that can inherit the state of lithium-ion batteries. The article presents the trend of introduction and widespread use of solid-state batteries in modern electric vehicles.

The Impact of Absorbed Solvent on the Performance of Solid Polymer Electrolytes for Use in Solid-State Lithium Batteries.

SummaryThe effects of solvent absorption on the electrochemical and mechanical properties of polymer electrolytes for use in solid-state batteries have been measured by researchers since the 1980s. These studies have shown that small amounts of absorbed solvent may increase ion mobility and decrease crystallinity in these materials. Even though many polymers and lithium salts are hygroscopic, the solvent content of these materials is rarely reported. As ppm-level solvent content may have important consequences for the lithium conductivity and crystallinity of these electrolytes, more widespread reporting is recommended. Here we illustrate that ppm-level solvent content can significantly increase ion mobility, and therefore the reported performance, in solid polymer electrolytes. Additionally, the impact of absorbed solvents on other battery components has not been widely investigated in all-solid-state battery systems. Therefore, comparisons will be made with systems that use liquid electrolytes to better understand the consequences of absorbed solvents on electrode performance.

Local Charge Inhomogeneity and Lithium Distribution in the Superionic Argyrodites Li6PS5X (X = Cl, Br, I).

The lithium argyrodites Li6PS5X (X = Cl, Br, I) exhibit high lithium-ion conductivities, making them promising candidates for use in solid-state batteries. These solid electrolytes can show considerable substitutional X-/S2- anion disorder, typically correlated with higher lithium-ion conductivities. The atomic-scale effects of this anion site disorder within the host lattice-in particular how lattice disorder modulates the lithium substructure-are not well understood. Here, we characterize the lithium substructure in Li6PS5X as a function of temperature and anion site disorder, using Rietveld refinements against temperature-dependent neutron diffraction data. Analysis of these high-resolution diffraction data reveals an additional lithium position previously unreported for Li6PS5X argyrodites, suggesting that the lithium conduction pathway in these materials differs from the most common model proposed in earlier studies. An analysis of the Li+ positions and their radial distributions reveals that greater inhomogeneity of the local anionic charge, due to X-/S2- site disorder, is associated with more spatially diffuse lithium distributions. This observed coupling of site disorder and lithium distribution provides a possible explanation for the enhanced lithium transport in anion-disordered lithium argyrodites and highlights the complex interplay between the anion configuration and lithium substructure in this family of superionic conductors.

Low-temperature paddlewheel effect in glassy solid electrolytes

Glasses are promising electrolytes for use in solid-state batteries. Nevertheless, due to their amorphous structure, the mechanisms that underlie their ionic conductivity remain poorly understood. Here, ab initio molecular dynamics is used to characterize migration processes in the prototype glass, 75Li2S–25P2S5. Lithium migration occurs via a mechanism that combines concerted motion of lithium ions with large, quasi-permanent reorientations of PS43− anions. This latter effect, known as the ‘paddlewheel’ mechanism, is typically observed in high-temperature crystalline polymorphs. In contrast to the behavior of crystalline materials, in the glass paddlewheel dynamics contribute to Lithium-ion mobility at room temperature. Paddlewheel contributions are confirmed by characterizing spatial, temporal, vibrational, and energetic correlations with Lithium motion. Furthermore, the dynamics in the glass differ from those in the stable crystalline analogue, γ-Li3PS4, where anion reorientations are negligible and ion mobility is reduced. These data imply that glasses containing complex anions, and in which covalent network formation is minimized, may exhibit paddlewheel dynamics at low temperature. Consequently, these systems may be fertile ground in the search for new solid electrolytes.

Lattice Dynamical Approach for Finding the Lithium Superionic Conductor Li3ErI6

Driven by the increasing attention that the superionic conductors Li3MX6 (M = Y, Er, In, La; X = Cl, Br, I) have gained recently for the use of solid-state batteries, and the idea that a softer, mo...

Native Defects and Their Doping Response in the Lithium Solid Electrolyte Li7La3Zr2O12

The Li-stuffed garnets LixM2M3′O12 are promising Li-ion solid electrolytes with potential use in solid-state batteries. One strategy for optimizing ionic conductivities in these materials is to tun...

Defect-Mediated Conductivity Enhancements in Na3–xPn1–xWxS4 (Pn = P, Sb) Using Aliovalent Substitutions

The sodium-ion conducting family of Na3PnS4, with Pn = P, Sb, has gained interest for the use in solid-state batteries due to their high ionic conductivity. However, significant improvements to the...

Ionic Liquid Electrolytes – from Novel Separators to Solid Polymer Electrolytes

One of the significant challenges to the application of ionic liquid electrolytes (ILE’s) is the ability to identify separators that can be effectively ‘wetted’ by the electrolyte. There has been significant work in identifying appropriate commercial separators for these electrolytes, with varying degrees of success [1]. To-date, the most effective separator for ILE’s is glass fibre, however, this material has large, open pore structure and this requires it to relatively thick to prevent short circuits between the electrodes. As a consequence, there is a need to identify new materials / structures that can lead to innovative separators that can allow ILE’s to be effectively used in batteries. To this end, we have examined the use of a “supported” electrospun membrane to be able to “tailor” the interfaces of the electrodes, but also allow effective wetting of the separator with an ILE to enable use in a lithium-ion battery [1]. However, in doing this, we have now made a “simple” separator far more complex in order to address the ILE wetting problem. So the question needs to be asked – can we combine the properties of the complex separator with an ILE into one solution, such as a solid polymer electrolyte? Further, can we improve these materials by exploiting micro-phase structured morphologies to provide us with enhanced mechanical properties as well? One type of these micro-phase structured polymers [2], known as PILBlox, is made of a high Tg block for mechanical strength and a low Tg ionic block for ionic conductivity [3, 4]. Combining PILBlox with a lithium based ionic salt and an ionic liquid forms a polymer electrolyte which ideally maintains the micro-phase separation present of the pure PILBlox polymer, and confines the ionic salt and ionic liquid to the ionic block of the polymer [4, 5]. In this presentation, we will describe our efforts to make innovative separators using electrospinning techniques and the resulting electrochemistry, before turning our attention to the PILBlox materials and examining their physical properties and their potential use in solid state batteries. References Francis. C., et al., manuscript in preparation, 2018.Bates, F.S., Polymer-Polymer Phase-Behavior. Science, 1991. 251(4996): p. 898-905.Dean, J.M., et al., Micellar structure and mechanical properties of block copolymer-modified epoxies. Journal of Polymer Science Part B-Polymer Physics, 2001. 39(23): p. 2996-3010.Nykaza, J.R., et al., Polymerized ionic liquid diblock copolymer as solid-state electrolyte and separator in lithium-ion battery. Polymer, 2016. 101: p. 311-318.Meek, K.M. and Y.A. Elabd, Polymerized ionic liquid block copolymers for electrochemical energy. Journal of Materials Chemistry A, 2015. 3(48): p. 24187-24194.

Structure of new electrolyte helps use in solid-state batteries

Structure of new electrolyte helps use in solid-state batteries

Lithium-ion conductive ceramic textile: A new architecture for flexible solid-state lithium metal batteries

Abstract Designing solid-state lithium metal batteries requires fast lithium-ion conductors, good electrochemical stability, and scalable processing approaches to device integration. In this work, we demonstrate a unique design for a flexible lithium-ion conducting ceramic textile with the above features for use in solid-state batteries. The ceramic textile was based on the garnet-type conductor Li7La3Zr2O12 and exhibited a range of desirable chemical and structural properties, including: lithium-ion conducting cubic structure, low density, multi-scale porosity, high surface area/volume ratio, and good flexibility. The solid garnet textile enabled reinforcement of a solid polymer electrolyte to achieve high lithium-ion conductivity and stable long-term Li cycling over 500 h without failure. The textile also provided an electrolyte framework when designing a 3D electrode to realize ultrahigh cathode loading (10.8 g/cm2 sulfur) for high-performance Li-metal batteries.

Influence of Protons on the Lithium Transport Mechanism in Antiperovskite Solid Electrolytes from Molecular Dynamics Simulations

Battery energy storage has become a critical component of civil and military operations because of the rapidly growing demands in consumer electronics, electric vehicles and the power-consuming systems carried by soldiers on the battlefield. Currently utilized batteries are flammable and suffer from an insufficient high specific energy, which poses major safety issues creating a tactical burden for the soldiers. The use of solid state batteries may offer enhanced safety and increased energy density. Previous modeling studies of the superionic lithium-rich anti-perovskites conductors focused on Li3OX (X = Cl, Br) structures and reported a variety of the charge transport mechanisms ranging from the low-barrier three-atom hop mechanism involving vacancies, Li hops to the nearest neighbor, Li interstitial dumbbells, and diffusion of the Li+ interstitials in LiCl-deficient Li3OCl that outnumber vacancies by 2–3 orders of magnitude as predicted by the shell model. It is, however, quite challenging to completely remove protons from these anti-perovskite conductors during synthesis, highlighting the importance of understanding the influence of protons on conductivity and electrochemical properties for these superionic lithium-rich anti-perovskite conductors.(1, 2) Born-Oppenheimer molecular dynamics (BOMD) simulations of Li2+xOH1-xCl (0≤x≤1) solid electrolytes were performed in order to gain insights into the mechanism of lithium transport and the influence of H concentration, complementing previous modeling studies of H-free antiperovskites. The simulation cell was comprised of 320 atoms. Density Functional Theory (DFT) calculations were performed with the QUICKSTEP module of the CP2K code, which implements the dual Gaussian and Plane Waves (GPW) method. The gamma point supercell approach was used in combination with 3-dimensioanl Periodic Boundary Conditions (PBC). Calculations were performed using the spin-polarized Perdew-Burke-Ernzerhof (PBE) exchange correlation functional with Grimme’s D3 dispersion correction. BOMD simulations predicted a significant enhancement of the lithium diffusion with the increased fraction of protons in agreement with experimental data. The lithium transport mechanism was found to be closely coupled with the rotation of a relatively short OH-group within the protonated electrolytes. Moreover, lithium jump events were found to be highly-correlated. Figure 1a shows a snapshot of the simulation box. In order to gain further insight into the transport mechanics, the motion of the fastest lithium cations in Li2.5OH0.5Cl solid electrolyte are highlighted with different colors. Overlap between trajectories of the fastest lithium cations shown by red arrows is indicative of the highly-correlated fashion of the lithium jumps.(2) We will also discuss changes of band gaps and band alignments that were calculated using DFT hybrid functionals as markers for electrochemical stability. We anticipate that our findings will reduce the existing confusions and show new avenues for tuning solid electrolyte compositions for further improved Li-ion conductivities. Different aspects of this work were supported by NASA Minority University Research and Education Project (MUREP; NASA grant NNX15AP44A and interagency agreement NND16AA29I with ARL for modeling) and ARPA-E (grant DE-AR0000779).