bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrode Design and Processing for Enhancing Performance of LiMn0.6Fe0.4PO4 Positive Electrode in Lithium-Ion Batteries
Authors: Go Nan Young , Cho Min Seo , Ryu Ji Heon
Published: December 2024

Lithium-ion batteries (LIBs) are used in various fields such as electronic devices and electric vehicles. The high energy density of LIBs has traditionally been a significant advantage. However, there is now an increasing demand for enhanced cost-effectiveness and safety. Phosphate-based positive electrode materials have been proposed as alternatives to Ni-based layered oxide materials. However, LiFePO4 is limited by its low operating voltage, leading to decreased energy density, while LiMnPO4 exhibits inadequate electrochemical performance. Consequently, there is increasing anticipation surrounding LMFP (LiMn1-xFexPO4), which leverages the benefits of combining Fe and Mn. LFMP offers the safety advantages of phosphate materials and the cost-effectiveness from the natural abundance of Fe and Mn, further enhanced by the complementary operating voltage and electrochemical activity derived from the Fe-Mn combination.

In this study, we conducted different studies depending on electrode design and manufacturing process in order to improve LiMn0.6Fe0.4PO4 (LMFP64) performance. To comprehend the typical characteristics of the LMFP64 positive electrode, various electrodes with differing compositions and loading levels were fabricated. The physical properties of the fabricated electrode were assessed, alongside the evaluation and comparison of electrochemical properties, including cycle performance and rate capability. Subsequently, modifications to the electrode design were made to incorporate new components or additives with the aim of improving LMFP electrode performance.

The electrode fabrication process was expanded to enhance the electrochemical performance of LMFP. Adjustments to the pore structure with electrode composition led to further performance improvements. Additionally, nano-sized LMFP powder was blended with commonly used micro-sized NCM-based active materials. Although the blending did not exhibit notable synergy, the higher electrode density was achieved than that of the individual electrodes and ensured the required electrode performance based on the properties of both active materials due to the appropriate mixing ratio. Thus, it becomes feasible to configure electrodes that align with user demands in terms of cost and performance, thereby diversifying the battery design.
A Mechanistic Way Triggering the Reversible Intercalation-Conversion Combined Chemistry for High Energy Density Lithium Ion Battery
Authors: Heo Jaehoon , Kang Kisuk
Published: December 2024

The current status of lithium-ion battery technology has approached its theoretical capacity ceiling, necessitating a reevaluation of the cathode material design strategy. Over the past several decades, intercalation and conversion reactions have been recognized as the predominant chemistries governing lithium-ion battery cathode materials. While each of these charge storage mechanisms individually enables the development of high-energy-density cathode materials, integrating both mechanisms within a single-phase material presents significant challenges. Intercalation hosts demand facile lithium-ion diffusion kinetics facilitated by a well-defined crystal structure, whereas the repeated conversion reactions, accompanied by structural reorganization, can compromise intercalation capabilities. Recently, our research group demonstrated the reversible operation of intercalation-conversion combined chemistry within a single-phase material, specifically amorphous LiFeSO4F. To elucidate the underlying factors enabling the reversible utilization of intercalation and conversion reactions, we established a model system using the tavorite phase LiFeSO4F and systematically manipulated its degree of amorphization. The investigation of electrochemical properties across varying degrees of amorphization, along with first-principle computational simulations, elucidated the role of the amorphous structure in facilitating intercalation-conversion combined chemistry. The amorphous structure was found to promote an increase in conversion redox voltage and facilitate conversion kinetics, thereby enabling the reversible utilization of intercalation-conversion chemistry. Furthermore, our studies revealed that certain intercalation host materials can reversibly utilize conversion reactions through amorphization. These findings suggest a new paradigm for cathode design that integrates intercalation and conversion reactions, thereby expanding the possibilities within cathode chemistry.
Operando FTIR Characterization of Interphases from Organosulfur Electrolytes in High Voltage Lithium-Ion Batteries
Authors: Liu Ziqi , Lopez Jeffrey
Published: December 2024

The widespread adoption of renewable energy storage technologies like electric vehicles and grid storage largely relies on the improvements of the energy density of the batteries inside those devices. Lithium-ion batteries (LIBs) are typically used for these applications due to their high energy density,[1] but the operating voltage of LIBs is limited by the electrochemical stability windows of the electrolyte. Resistive interphase layers form as a result of the breakdown of electrolyte molecules and limit LIB cycling stability. However, there is significant difficulty in the study and characterization of both the components and structure of the electrode-electrolyte interphases formed via electrolyte degradation.[2] Traditional characterization techniques provide information on what the interphase layers look like after cell disassembly, but sample preparations are difficult and destructive.[3] Therefore, it is crucial to develop in operando techniques to better understand the relationship between the interphase layers and battery performance.

In this work, we develop a custom surface-enhanced infrared absorption spectroscopy in the attenuated total reflectance mode (ATR-SEIRAS) setup for in operando studies of the solid electrolyte interphase (SEI) and cathode electrolyte interphase (CEI) in organosulfur electrolyte systems. Organosulfur molecules are potential components for high voltage LIBs due to their excellent performance.[4] We apply our custom ATR-SEIRAS setup to study ethyl methyl sulfone (EMS) containing electrolytes and propose possible reduction routes with the help of ex situ and postmortem characterization techniques. We study both SEI and CEI formed and correlate favorable interphase components with contributing molecules to identify important functional groups for novel molecular design. The work provides an opportunity to elevate our understanding of currently elusive electrochemical phenomena like the structure-reactivity relationships of SEI and CEI, and why certain sulfone systems outperform other formulations. Furthermore, it will provide molecular design principle for electrolyte systems in high performing and high voltage LIBs.

References

S. Chu, Y. Cui, and N. Liu, Nat. Mater., 16, 16–22 (2017).

H. Wan, J. Xu, and C. Wang, Nat. Rev. Chem., 8, 30–44 (2024).

A. Dopilka, Y. Gu, J. M. Larson, V. Zorba, and R. Kostecki, ACS Appl. Mater. Interfaces, 15, 6755–6767 (2023).

M. A. Dato et al., Adv. Energy Mater., 2303794 (2024).
Anode Properties of Si-Based Composite Electrodes Containing Two Silicides with Different Functions for Lithium-Ion Batteries
Authors: Tanaka Ryuto , Domi Yasuhiro , Usui Hiroyuki , Yamaga Takuya , Nishikawa Kei , Sakaguchi Hiroki
Published: December 2024

A LaSi2/Si composite electrode has longer charge-discharge cycle life than a pure Si electrode. However, the capacity of the composite electrode decreases gradually over repeated cycles. We identified the microstructure of the electrode to ascertain factor of capacity fading by transmission electron microscopy. Before cycling, the pure Si phase was highly dispersed in the LaSi2 matrix phase. In such microstructure, the elastic LaSi2 could alleviate the stress caused by Si volume change during lithiation and delithiation; and hence it suppressed electrode disintegration.1 On the other hand, prior to capacity decline, the positions of LaSi2 and pure Si were reversed. The LaSi2 phase was surrounded by the pure Si matrix phase and the LaSi2 could not relax the stress. Hence, we added stiff silicide which withstands the Si-generated stress into the LaSi2/Si. As a result, the LaSi2/NbSi2/Si exhibited superior cycle life. Herein, we investigated the effect of difference in elastic silicides on cycle life.

The MSi2/CrSi2/Si (M = Ni, La, or Sm) powder was prepared by mechanical alloying method. The composite powder was deposited on the Cu substrate using a gas-deposition (GD) method. The fabricated GD electrode was mounted in a 2032-type coin-cell as the working electrode. Li metal foil and glass fiber filter were also used as the counter electrode and separator, respectively. In addition, we used 1 mol dm–3 lithium bis(fluorosulfonyl)amide dissolved in N-methyl-N-propylpyrrolidinium bis(fluorosulfonyl)amide as an ionic liquid electrolyte. We conducted galvanostatic charge-discharge tests in constant current mode with a charge capacity limitation of 1000 mA h g(Si)–1. In the present study, we did not consider the capacity of the silicides: the Si-alone and silicide-alone electrodes stored Li, while the silicide in the silicide/Si electrodes did not show the reversible capacity2.

Figure 1 shows the cycle life of the MSi2/CrSi2/Si electrodes with the different indentation work rates of MSi2. The indentation work rate means an indicator of elasticity: it indicates that how much the MSi2 layer returns to its original shape after deformation. The cycle life was the shortest when NiSi2 with the lowest indentation work rate was used. In contrast, when SmSi2 was used, it achieved the longest cycle life with high reversible capacity of 1000 mA h g(Si)–1 over 1900 cycles. We predicted that the cycle life improved using a more elastic silicide. However, the cycle life adversely lowered when LaSi2 with the highest elasticity was used. Thus, the excellent performance should be achieved based on the synergistic effects of stiff and elastic silicides.

1) Y. Domi, H. Usui, K. Nishikawa, and H. Sakaguchi, ACS Appl. Nano Mater., 4, 8473 (2021).

2) Y. Domi, H. Usui, K. Nishikawa, H. Sakaguchi, et al., Electrochemistry, 88, 548 (2020).

Figure 1
Exploring the Relationship between Ion Diffusion and Molecular Structure of Gel Polymer Electrolytes Using NMR Spectroscopy
Authors: Kim Dokyung , Seo So Jung , Seo Ji-Hun , Lee Young Joo
Published: December 2024

Lithium rechargeable batteries are widely used as energy sources for portable electronic devices, automobile, and wearable electronics. However, concerns regarding fire hazards have prompted efforts to transition from liquid to solid electrolytes. Gel polymer electrolytes (GPEs) have emerged as promising alternatives for enhancing the safety of lithium batteries. The ion conduction mechanism in GPEs can be conceptualized in two distinct modes: a liquid-like mechanism and a solid-like mechanism. We focus on the investigation of the liquid-like mechanism, which relies on polymer segmental motion. Various factors can influence ionic conduction of gel polymer electrolytes such as the structure of the sidechain, interaction between sidechain and ionic species etc. We utilize PFG NMR and nuclear relaxation time measurements to explore the correlation between the ionic motion and the structure of polymers and ionic liquids. Chain length of polymer sidechain will be varied and structurally isomeric ionic liquids will be utilized. We will demonstrate that NMR spectroscopy is a good indicator to examine the dynamics of the gel polymer electrolyte. Understanding of the structure-dynamics relation from our study will serve as a design principle to develop new gel polymer electrolyte with desired properties.
Postmortem Lithium-7 NMR Analysis to Evaluate the Reversibility of Lithium Metal Electrodes and the Behavior of Li+ in Lithium Metal Batteries
Authors: Baek Jaewon , Kim Sun Ha , Kim Hee-Tak , Han Oc Hee
Published: December 2024

Solid-state 7Li NMR spectroscopy is highly effective in monitoring the physical and chemical states of Li metal electrodes. In this study, we employed postmortem 7Li NMR spectroscopy with an ordinary magic angle spinning (MAS) probe to evaluate the reversibility of lithium metal electrodes and the behavior of Li+ in lithium metal batteries(LMBs). Through contrasting NMR spectra of a protective layer(PL)-coated Li metal and LiAg alloy electrodes against bare Li electrodes before and after cycling, we identified alterations in Li0 and Li+ signals attributable to the degradation of the Li metal electrode and efficacy of the protective layer in mitigating dendrite and the solid electrolyte interphase formation. Investigation on Li electrodes after different number of electrochemical cycles revealed the more dendritic Li metal formation through the more number of cycles. In addition, our investigation showed that rinsing and drying the electrode-separator-electrode assemblies extracted from LMBs altered the physical and chemical states of the battery constituents. This study provides valuable insights and practical guidelines for characterizing distinct lithium states in LMBs using 7Li NMR spectroscopy.
Enhancement of Electrochemical Properties of Carboxylate-Based Single-Ion Conducting Polymers through Complexation with Ionic Liquids for Lithium-Ion Batteries
Authors: Kim Dongwook , Okada Shizuka , Nakajima Hideto , Inokuchi Daisuke , Yamada Izumi , Hwang Jinkwang , Abe Takeshi , Ouchi Makoto , Matsumoto Kazuhiko , Inui Naoki
Published: December 2024

[Introduction] Single-ion conducting (SIC) polymers, wherein anions are covalently bonded to the polymer chain, selectively facilitate the movement of lithium ions, making them promising polymer electrolytes for lithium-ion batteries (LIBs) due to their high lithium-ion transference number. However, in the application of highly basic carboxylate-based SIC polymer electrolytes, there is a drawback of difficultly in dissociating Li+ ions. In this study, the complexation with ionic liquids (ILs) was investigated to promote the dissociation of Li+ ions.

[Experiment] The carboxylate-based SIC polymer (MAA-St) was synthesized through a 1:1 radical copolymerization of methacrylic acid derivatives and styrene. A polymer electrolyte was fabricated by compounding the obtained polymer with ILs, and its electrochemical properties were evaluated.

[Results and Discussion] Electrochemical evaluations were conducted on the polymer electrolyte, which was a composite of MAA-St and ILs. In the absence of ILs, the ionic conductivity (σ = 7.13×10–4 mS cm–1 at room temperature) and critical current density (CCD) were extremely low because of the high basicity and difficulty in dissociating Li+ ions. However, the incorporation of ILs led to a significant improvement in electrochemical properties (σ = 7.13×10–4 → 1.98 mS cm–1, critical current density = 0.1 → 2.1 mA cm–2). Furthermore, ionic conductivity and CCD were substantially enhanced with an increase in the quantity of ILs (Figure 1). The addition of ILs weakened the interaction between the SIC polymer and Li ions, facilitating the dissociation of Li ions.

The effect of ionic species of ILs on electrochemical properties was investigated. To examine the dependence on anion species, the cation of the IL was fixed to (N-butyl-N-methylpyrrolidinium: P14
+) and five different anions (PF6, TFSA, FSA, OTf, and N(CN)2) were used for evaluation. As a result, it was observed that the CCD varied significantly according to the donor number (DN) of the anion species. On the other hand, the impact of cation species on CCD was minimal because they interacted with the anionic part of the SIC polymer.

The interaction between SIC polymer and ILs was observed through IR measurements, and the peak of the polymer-derived carbonyl group (C=O) underwent significant changes upon the addition of ILs (1680 cm–1: substantial decrease, 1572 cm–1: red-shift). Additionally, the movement of the anion species of the IL was confirmed by Raman spectroscopy, revealing distinct movements based on the DN of the anion species. Consequently, it became evident that the interaction between SIC polymer and ILs results in the dissociation of Li+ ions and the counteranions.

Figure 1
H-Cell Evaluation of Electrolyte Solvation Energies in the Presence of Silicon Electrodes
Authors: McBrayer Josefine , Schulze Maxwell C. , Rich Chaz , Harrison Katharine L.
Published: December 2024

Poor calendar life of Li-ion batteries with silicon anodes has been identified as an important obstacle that must be addressed for silicon to be fully commercialized in applications such as electric vehicles. The silicon-electrolyte interface likely plays a key role in calendar life performance since silicon’s reactivity and unstable solid electrolyte interphase (SEI) may lead to increased lithium loss and self discharge. New electrolytes that will better stabilize the SEI are a promising direction to improve calendar life. We hypothesize that the solvation energy of lithium ions in the electrolyte is related to observed lifetimes. Here, we use an H-cell, demonstrated previously as a method to quantify relative solvation energies of Li-ions in promising electrolytes to improve silicon calendar life and compare to performance data. We observe that the solvation energy is dependent on the electrode present, giving further credence to the need to optimize the electrolyte specifically for silicon anodes, accounting for both cycle and calendar life.

Sandia National Laboratories is a multimission laboratory managed and operated by the National Technology and Engineering Solutions of Sandia, LLC (NTESS), a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration (DOE/NNSA) under contract DE-NA0003525. This written work is authored by an employee of NTESS. The employee, not NTESS, owns the right, title and interest in and to the written work and is responsible for its contents. Any subjective views or opinions that might be expressed in the written work do not necessarily represent the views of the U.S. Government. The publisher acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this written work or allow others to do so, for U.S. Government purposes. The DOE will provide public access to results of federally sponsored research in accordance with the DOE Public Access Plan.

Figure 1
Electrolytes Towards High Voltage Mn-Rich Cathodes
Authors: Liu Qian , Zhu Qijia , Zhang Zhengcheng
Published: December 2024

Earth-abundant, sustainable Mn based cathode materials become an attractive option due to the arising concerns of safety, cost, and material availability. Among this class, the Li-rich, Mn-rich (LMR) layered-structure cathode materials show promise due to their high galvanometric energy density. However, the challenge of Mn dissolution/deposition persists, posing a significant hurdle to the long-term performance of LMR cathodes and playing a crucial role in the capacity fade of LMR. In this presentation, the electrolyte design to mitigate Mn dissolution will be discussed. Through the removal of highly solvating solvents like ethylene carbonate (EC) and the introduction of low-solvating solvents, it becomes possible to effectively prevent Mn dissolution, leading to significantly improved cyclability. Ion chromatography and ICP-MS were employed to analyze the amount of dissolved Mn in the electrolyte and its deposition on the anode.
An Unwanted Guest in the Electrochemical Oxidation of High-Voltage Li-Ion Battery Electrolytes: The Life of a Superacidic Proton
Authors: Ilic Stefan , Zorko Milena , Farinazzo Bergamo Dias Martins Pedro , Liu Haoyu , Yang Jingtian , Zhang Zhengcheng , Connell Justin G. , Key Baris , Cabana Jordi , Strmcnik Dusan
Published: December 2024

Lithium-ion batteries (LIBs) are central to the urgent societal need to decarbonize both transportation and energy storage on the grid. Unfortunately, despite their attractive energy/power density and high coulombic efficiency, further improvement of this technology – especially their durability – is desperately needed. To support these efforts, our study focuses on fundamental understanding of the decomposition pathways for LIB electrolytes at the cathode-electrolyte interface (CEI), as the nature of these reactions directly controls the extent to which cell capacity and voltage decays in these systems. In this study, we employ electrochemical methods, coupled with product analysis using NMR spectroscopy and mass spectrometry, to determine the decomposition mechanisms for a model electrolyte (1.3 M LiClO4 in EC) and demonstrate the impact of these mechanisms on technologically relevant systems (1.0 M LiPF6 in EC/EMC). Remarkably, we discover the electrochemical formation of superacidic protons, which provides a unified origin for a myriad of side reactions in every individual component of the CEI. In particular, electrochemically generated protons chemically catalyze EC decomposition into CO2 and other short and long chain ethers. They also react with LiPF6 to form the weaker acid HF and are involved in a direct acid-base reaction with the cathode active material, causing the leaching of transition metals into the electrolyte. Collectively, the results of this study all point to the urgent need to either mitigate this proton formation or introduce benign harvesting additives via new electrolyte design strategies.

___________________

The submitted manuscript has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory (“Argonne”). Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357. The U.S. Government retains for itself, and others acting on its behalf, a paid-up nonexclusive, irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan. http://energy.gov/downloads/doe-public-access-plan
Development of Eco-Friendly Binders for Silicon Anodes in All-Solid-State Batteries Under Low Operating Pressure
Authors: Jun Seunggoo , Lim Haechannara , Song Yongbae , Jung Yoon Seok
Published: December 2024

The growing demand for vehicle electrification and sophisticated energy storage systems is driving research into lithium-ion batteries (LIBs) with high energy density. Employing inorganic materials as solid electrolytes (SEs) presents a compelling strategy to enhance the energy density and safety profile of these batteries. Nonetheless, the integration of Li metal anodes (LMAs) in all-solid-state batteries (ASSBs) still presents dendrite issues, and without specific protective layers like C-Ag, cycle stability remains a challenge. In contrast, Si anodes, which are not subject to these limitations, may offer a viable alternative. However, Si anodes in LIBs are prone to extreme volume expansion (> 300%) during charge-discharge cycles, causing fractures and loss of electrical contact. Si ASSBs can have electrodes in the form of pure Si and a composite with the SEs. Recent studies suggest that each exhibits different failure mechanisms. Specifically, in the case of pure Si, numerous vertical cracks in the electrode and delamination with SE layer have been reported. In low-operating pressure, the resistance to electronic conduction in Si anode is further exacerbated. ASSBs present significant environmental concerns related to their manufacturing and recycling processes, which frequently incorporate hazardous substances such as NMP solvent and fluorinated polymers, including PVDF and PTFE. To commercialize ASSBs, two issues must be resolved.

In our study, we designed an aqueous-process-based binder for eco-friendly strategies and utilized it for low pressure operating Si ASSBs. Additionally, the binder significantly contributes improving electrical conductivity during the delithiation process with adhesion properties, as observed by an electrical conductivity measurement cell. The NCM/Si full cell exhibited high discharge capacity at 30°C and 5 MPa with high rates. Our design demonstrates enhanced performance of ASSBs under reduced pressure conditions, addressing a critical aspect of practical applicability.

[1] H. S. Tan Darren et al., Science 2021, 373, 1494.

[2] H. Huo et al., Nat. Mater. 2024, 23, 543.
Surface Reaction of Argyrodite-Type Sulfide Solid Electrolyte in Air with a Dew Point of −20°C
Authors: Sano Hikaru , Otoyama Misae , Morino Yusuke , Ito Daisuke
Published: December 2024

Sulfide solid electrolytes are expected to be used for practical all solid-state batteries because they combine high formability with high ionic conductivity. However, unlike oxide and organic solid electrolytes, sulfide solid electrolytes have problems such as toxic hydrogen sulfide generation and conductivity degradation due to even slight moisture. In this study, we investigated the details of the denaturation of argyrodite-type sulfide solid electrolyte (ASSE) by a small amount of water, with the aim of further increasing the water resistance of ASSE. The denaturation of ASSE in air with moisture at the dew point −20 °C, which is comparable to a typical dry room environment, was already reported; EIS and XRD revealed only the surface of ASSE degraded by moisture in the air. Surface analysis was also conducted and revealed that surface degraded components such as Li2CO3, Li2SO4 are formed on the surface.

In this study, the effects of oxygen and carbon dioxide were also examined in addition to water. Details of the denaturation was investigated using XRD, XPS, IR and Raman. This investigation revealed that the denaturant is formed only on the surface by moisture, that the denaturant is oxidized by oxygen, and that Li2CO3 is formed by carbon dioxide. More details will be discussed at the meeting site.
Thin-Film Glassy Solid Electrolytes: A New Functionality for Glass Enabling High Energy Density All Solid State Batteries
Authors: Martin Steve
Published: December 2024

Fast ion conducting glasses have long been considered as alternatives to flammable liquid electrolytes in Li batteries. However, to date, there has never been before the unique combination of required electrochemical properties in any one such glass for its use as a solid electrolyte with the equally important requirements of viscoelastic behavior to form them into thin films suitable for high ion conductivity separators. In this first ever report of thin film fast ion conducting glasses, we will summarize our efforts to produce thin films of ion conducting glasses and test in them in symmetric, asymmetric, and full cells.
Synthesis Mechanisms of over-Stoichiometric Rocksalt-Type Li Superionic Conductors
Authors: Zhao Xinye , Chen Yu , Ceder Gerbrand
Published: December 2024

Oxides materials with a face-centered cubic (fcc) anion sublattice are generally unsuitable for use as solid-state electrolytes as such structural framework typically exhibits high migration energy barrier, preventing a facile Li transport [1,2]. A recent discovery involving a class of over-stoichiometric rocksalt (ORX) compounds has shown promise for achieving fast Li conduction in oxide materials by introducing Li-Li face-sharing configurations in a spinel-like arrangement (s-phase) [3]. In general, it is challenging to create rocksalts in which the cation to anion ratio is larger than 1. As a result, the fast-conducting s-phase has been observed to be formed only in nano-sized domains that originate through a specific cooling process from a high-temperature disordered rocksalt. To further optimize the ORX-based Li superionic conductors, we conducted a systematic study combining first-principles calculations and experiments to understand the formation mechanism of the s-phase. Taking the reported ORX-Li17In9SnO24 material as a prototype compound, we explored the detailed thermodynamic landscape in the Li-In-Sn-O (LISO) space, comparing the stability of several competing phases at different synthesis temperatures. Our insights into the synthesizability of s-phase have led to large improvements in Li conductivity in ORX-LISO compounds compared to the previous report [3]. In this presentation, we will present the key thermodynamic and kinetic mechanisms governing the formation of the unusual s-phase and discuss how a combination of equilibrium and non-equilibrium routes can be applied to synthesize a general ORX compound for solid-state electrolyte application.

[1] Z. Zhang et al., Energy
Environ. Sci. 11, 1945–1976 (2018).

[2] K. J. Kim, M. Balaish, M. Wadaguchi, L. Kong and J. L. M. Rupp, Adv. Energy
Mater. 11, 2002689 (2020).

[3] Y. Chen, Z. Lun, X. Zhao et al., Nat. Mater. 23, 535–542 (2024).
Origin of High Ionic Conductivity in Nasicon Type Ionic Conductors
Authors: He Yufang , Shaji Ajay , Scivally Elena , Ouyang Bin , Zeng Yan
Published: December 2024

Solid-state electrolytes that are nonflammable and exhibit high ionic conductivity are essential for enhancing the safety and increasing the energy density of all-solid-state batteries (ASSBs). The Na superionic conductor (NASICON) framework is extensively researched as a potential solid-state electrolyte because of its ability to achieve high ionic conductivity. Various theories have been proposed to explain the origins of this high ionic conductivity in NASICON, which led to both overlaps and ambiguities. In our presentation, we will present a comprehensive theoretical framework, supported by experimental verification with controlled variables, that consolidates all known mechanisms to boost ionic conductivity in NASICON.
Electrodeposited High-Voltage Cathodes for Next-Generation Solid-State Batteries
Authors: Shyam Badri , Joshi Prerna , Anderson Tanner , Zahiri Beniamin , Yang Heng , Cook John B. , Braun Paul V. , Busbee John
Published: December 2024

Dense, monolithic high-voltage cathodes have direct implications for a step-change advance in the specific energy and energy density of next-generation solid-state batteries (SSBs) which offer several advantages over traditional Li-ion batteries (LIBs). Solid electrolytes possess improved chemical stability with Li metal, dimensional stability (enabling separate electrolyte optimization for low and high voltages along with the possibility of bipolar stacking), and wider thermal stability than liquid electrolytes. Consequently, SSBs can offer higher specific energy, wider operating voltage and temperature windows, and potentially improved safety at the cell level.

Xerion’s dense LiCoO2 (DirectPlateTM LCO) cathodes are fabricated via a novel, high-temperature molten salt electrodeposition process and are distinctly different from conventional slurry-cast electrodes. They combine several advantages for next-generation SSBs. They are strongly bonded to the current collector foil, highly dense (typically < 10% porosity) with no catholyte requirement, can be tailored with a dominant crystal orientation based on electrodeposition conditions, and do not contain any carbon or polymer additives known to lead to parasitic side-reactions in SSBs. Taken together, at the cell-level, the effect is a direct increase in both the specific energy (Wh/kg) due to increase in cathode active material, as well as energy density (Wh/l) due to lower porosity. The electrode architecture and cell configuration for Xerion-based SSBs closely resembles the classic layer-by-layer fabrication approach used for thin film batteries (TFBs) but possesses much larger cell capacities, enabling the use of this cathode architecture for the consumer electronics market (100 mAh to 5 Ah).

In this talk, I will showcase Xerion’s molten salt electrodeposition platform as well as the electrochemical properties of Xerion’s DirectPlateTM LiCoO2 cathodes with an emphasis on their performance in SSBs. I will discuss a) the effects of cathode crystal orientation and the electrode-electrolyte interface on cell performance, and b) the merits of using Xerion’s dense cathode architecture compared to composite cathodes containing solid electrolyte (as catholyte). I will conclude with the performance and safety implications of cathode porosity and surface roughness of Xerion’s DirectPlateTM LCO cathodes.
Low-Temperature Sintering of NASICON-Type LAGP Its Application to All-Solid-State Batteries
Authors: Yamada Hirotoshi , Yamasaki Ryoya , Onoue Yusuke , Matsumoto Kazuki
Published: December 2024

All-solid-state batteries (ASSBs) are one of the next-generation batteries towards carbon neutral societies. While sulfide-based ASSBs are on the stage for their practical application, oxide-based ones are still under the feasibility studies, mainly because of their interfacial issues: interphases and/or contact areas that would limit the energy and the power of the ASSBs. These issues are more severe for the full-inorganic ASSBs without any organic electrolytes, although they would extend the application fields of the next-generation batteries: high voltage batteries and batteries for severer environment (vacuum, high temperature, etc.). In this study, materials and processes of NASICON-type solid electrolytes are developed to prepare the electrochemically active interfaces between the solid electrolytes and the active materials.

For the NASICON ASSBs, Li1.5Al0.5Ge1.5(PO4)3 (LAGP) was prepared by a solution method using oxalic acid as a chelate. LAGP obtained by sintering the precursor at 600°C exhibited rather high total conductivity of 2 × 10−5 S/cm, which was further increased to 1.6 × 10−4 S/cm by mild-hot-pressing at 10 MPa. The NASICON ASSBs fabricated with TiO2 anode (2.5 mg/cm2) and LiCoPO4 cathode exhibited an initial discharge capacity of 66 mAh/g (0.17 mAh/cm2).

The study demonstrated that 3V-class ASSBs worked at room temperature, although the ASSB has not been optimized yet. The performance of the NASICON-based ASSBs would be further improved by optimizing materials/processes/architecture towards novel batteries.

Figure 1
Orientation Control of Perovskite Electrolyte Using Phase Transformation from Ruddlesden-Popper Type Nanoplate Synthesized By Hydrothermal Reaction
Authors: Mimura Kenichi , Itasaka Hiroki , Hamao Naoki , Liu Zheng , Hamamoto Koichi
Published: December 2024

Oxide type all-solid-state battery has attracted a great deal of attention its high energy density and safety. Perovskite-type (Li3x,La2/3-x)TiO3 (LLTO) has high ionic conductivity and it is one of the candidate electrolyte for an all-solid-state battery. Various efforts are underway to improve the properties. Facet-controlled nanocrystals can assemble into highly ordered nanostructures, and their orientation control and epitaxial grain growth during sintering are expected to improve their electrical properties. In this study, we focused on the orientation of LLTO ceramics. To control the orientation of electrolyte, we tried to fabricate perovskite LLTO platelet nanocrystals (nanoplates). LLTO nanoplates were synthesized by hydrothermal reaction using aqueous Ti complex as a starting material and NaOH as a mineralizer [1]. The pellet made from LLTO nanoplates is sintered at 1000 ºC which is lower sintering temperature than LLTO microparticles. However, the ionic conductivity is as low as 10-6 S/cm. STEM-EDX analysis revealed that this is due to the Na ions remaining at the Li site of the perovskite structure. We found that Ruddlesden-Popper (R-P) type layered perovskite Li2La2Ti3O10 nanoplates can be synthesized by selecting LiOH instead of NaOH as the mineralizer to prevent substitution of Li to Na ion. The R-P nanoplate is a single crystal having c-plane of R-P phase. The pellet made from R-P nanoplate has highly orientation of c-axis along to the press direction. This pellet is also able to sinter relatively low temperature at 1200 ºC with keeping orientation, but R-P phase shows extremely low ionic conductivity of 3.2x10-8 S/cm. As Li site of R-P phase is fully occupied by Li ion, Li ions are difficult to move. However, ionic conductivity of the direction of c-plane is higher than that of the c-axis direction. This result suggests that Li ion is located interlayer and Li ion is easy to move in c-plane of R-P structure. When this pellet is sintered at 1400 ºC, R-P phase has transformed to perovskite LLTO with keeping orientation. Transformation to perovskite phase is caused by vaporization of Li ion from R-P structure and it shows good conductivity of 1.1x10-4 S/cm.

Reference

[1] K. Mimura, N. Hamao, H. Itasaka, Z. Liu, K. Hamamoto, J. Sol-Gel Sci. Tech. 104, 599 (2022).

Acknowledgement: This study is based on results obtained from a project, JPNP20005, subsidized by the New Energy and Industrial Technology Development Organization (NEDO).
From Useless to Useful - Particle Engineered Li6PS5Cl for Solid-State Pouch Cells
Authors: Malmer Mika Serna , Tran Quoc-Anh , Agrawal Meenal , Ellingsen Ingeborg Sellæg , Häusler Michael , Brunner Roland , Zettl Roman , Hennige Volker , Mehraj Ud Din Mir , Rettenwander Daniel , Fadillah Laras
Published: December 2024

Solid-state batteries have been pointed out as a promising battery technology for the future, as it offers solutions to common issues with Li-ion batteries, especially regarding safety concerns due to the flammable nature of the liquid electrolyte. Additionally, the potential volumetric and gravimetric energy densities of solid-state batteries are expected to surpass the ones of Li-ion batteries.1 Despite significant progress in developing solid-state batteries, the pathway from successful lab-scale cells to more commercially viable pouch cells remains a major bottleneck towards their commercialisation. This is especially true with the use of inorganic solid electrolytes.2,3

Recent studies have shown that the particle size ratio between the cathode material and the solid electrolyte plays a key role to achieve low tortuosity, hence, increasing power density. However, commercially available products suffer from wide particle size distributions with chunks of particles even larger than the composite cathode thickness, which introduces challenges in respect of the densification, leading to poor kinetics.

This study focuses on the optimisation of LPSCl particles and the subsequent densification of slurry-based casted LPSCl tapes and monolayer pouch cells (composed by Si anodes and NMC811 cathodes) as a function of the LPSCl particle size distribution and the pre-pressing conditions. A wide variety of characterization tools are applied, such as FIB-SEM, X-ray computed tomography, and temperature and pressure dependent impedance spectroscopy to correlate microstructure with Li-ion transport, as well as galvanostatic cycling to link them to cell performance.

References

Janek, J. & Zeier, W. G. A solid future for battery development. Nat Energy
1, (2016).

Wang, C., Kim, J. T., Wang, C. & Sun, X. Progress and Prospects of Inorganic Solid‐State Electrolyte‐Based All‐Solid‐State Pouch Cells. Advanced Materials
35, (2023).

Wang, C. et al. All-solid-state lithium batteries enabled by sulfide electrolytes: From fundamental research to practical engineering design. Energy and Environmental Science
14, (2021).
Tuning the Properties of PEO/PAN-Based Electrospun Membranes for Solid-State Li- and Na-Ion Batteries
Authors: Springl Elisabeth , Nilges Tom
Published: December 2024

Long-term independence from fossil and nuclear energy sources is essential to achieve the 1.5-degree target of the Paris Agreement and reduce dependence on energy imports [1]. Expanding electromobility is crucial in the transport sector to reduce CO2 emissions. Lithium-ion batteries (LIBs) are the key technology for the mobility transition and storage of renewable energy from wind, water, and sun. Thermal, electrical, or mechanical mishandling of lithium-ion batteries can cause thermal runaways and battery failure. Replacing the liquid electrolyte with a solid one in a so-called all-solid-state battery system can minimize the risk of these LIBs malfunctions [2]. Solid polymer electrolytes, standing out for their mechanical flexibility and electrochemical stability, are among the most promising candidates for replacing liquid-based electrolytes in LIBs [3]. Here, we present a solid polymer electrolyte based on a polyacrylonitrile (PAN) and polyethylene oxide (PEO) blend, whose mechanical flexibility and suppressed crystallinity are ensured by the production technique electrospinning.

Adding the structure-giving polymer PAN to the ion-conducting polymer PEO leads to a free-standing membrane with enhanced thermal stability up to 100 °C, above the melting point of PEO, which is checked using scanning electron microscopy. The arising beneficial phase-separated fiber structure and its resulting properties, such as morphology and conductivity, can be tuned and optimized by the production parameters of electrospinning. If the composition of polymer to plasticizer and conducting salt is kept constant, low humidity during the electrospinning process and a short period between the production of the polymer electrolyte and its drying in vacuo, as well as an enhanced drying procedure, lower the porosity and increase the ionic conductivity by up to two orders of magnitude to 0.4 mScm-1 at 328 K. We ensured the capability of reversible lithium transport through the membrane in a symmetric Li-metal|polymer-electrolye|Li-metal cell. Furthermore, we compared our lithium-based system with a sodium system, following a beyond-lithium approach, both with the bis(trifluoromethanesulfonyl)imide-anion. All polymer membranes’ crystallinity was analyzed by X-ray diffraction, and their conductivity and activation energy were determined by impedance spectroscopy and using the Arrhenius equation. Swapping lithium with more abundant sodium leads to a decrease in conductivity of one order of magnitude. The elastic, free-standing membranes with a dense fiber structure show the great potential of electrospun solid polymer electrolytes in all-solid-state batteries.

References

[1] Paris Agreement to the United Nations Framework Convention on Climate Change, T.I.A.S. 16, 1104 (2015).

[2] Q. Wang, B. Mao, S. I. Stoliarov and J. Sun, Prog. Energy Combust. Sci.,
73, 95–131 (2019).

[3] Y. Zhao, L. Wang, Y. Zhou, Z. Liang, N. Tavajohi, B. Li and T. Li, Adv. Sci.,
8(7), 2003675 (2021).
Improvement of Grain-Boundary Resistance of Li7La3Zr2O12 By Coating with Li2CO3: A Study on Improving Electrochemical Performance of All-Solid-State Batteries
Authors: Park Jae-Wan , Shim Jae-Hyun
Published: December 2024

In recent years, the primary concern in the electric vehicle (EV) market has been the short driving range and long charging times associated with single charges. However, the market is now facing another bottleneck due to safety issues. Lithium-ion batteries (LIBs) utilizing organic liquid electrolytes pose significant safety risks due to their low thermal stability and high fire hazard. To address this fundamental issue, there is a push to replace liquid electrolytes in current LIBs with solid-state electrolytes (SSEs). Among the materials used as electrolytes in solid-state batteries, oxide-based SSEs offer a wider potential window of 5 V or more compared to organic liquid electrolytes (<4.5 V). Their high elastic modulus and ion conductivity enable them to suppress the growth of lithium dendrites, allowing for the use of high-capacity lithium metal as the anode material. Additionally, oxide-based SSEs possess advantages such as high stability in air, high mechanical strength, and high oxidation voltage. However, they also exhibit higher interfacial resistance and lower lithium ion conductivity than sulfide-based SSEs, typically reported in the range of 10⁻³ ~ 10⁻⁴ S/cm.

This study focused on enhancing the grain-boundary resistance of Li7La3Zr2O12 (LLZO) by coating its surface with Li2CO3. LLZO pellets were coated with Li2CO3 through a solution process and then sintered to form a solid-state electrolyte. X-ray diffraction (XRD) was utilized to analyze the crystal structure of the sintered LLZO pellets, while scanning electron microscopy (SEM) was used to evaluate the density of constituent elements and the surface structure. Electrochemical impedance spectroscopy (EIS) was employed to observe changes in lithium ion conductivity due to grain-boundary properties. The results demonstrated that Li2CO3-coated LLZO pellets exhibited lower grain-boundary resistance and higher lithium ion conductivity compared to uncoated LLZO pellets. Finally, all-solid-state batteries (ASSBs) were fabricated using the sintered Li2CO3-coated LLZO pellets, and their electrochemical properties were evaluated to predict improvements in battery performance due to grain-boundary properties. The findings of this study suggest that coating LLZO with Li2CO3 can significantly enhance the grain-boundary resistance and performance of all-solid-state batteries.
Traveling Solvent Floating Zone Growth and Ionic Conductivity of Li0.1La0.3Nb0.8Ta0.2O3 Single Crystals
Authors: Onimaru Mizuki , Maruyama Yuki , Nagao Masanori , Watauchi Satoshi , Tanaka Isao
Published: December 2024

Li
x
La(1-x)/3Nb1-y
Ta
y
O3 (LLNT) is a solid electrolyte with a double perovskite-type structure. It was reported that the highest ion conductivity of LLNT was 7.78 × 10-5 S/cm at x = 0.1, y = 0.2 [1,2]. Therefore, in this study, we investigated the preparation conditions of the feed and the growth conditions of Li0.1La0.3Nb0.8Ta0.2O3 single crystals by the traveling solvent floating zone (TSFZ) method.

Li2CO3, La2O3, Nb2O5, and Ta2O5 were used as starting materials, weighed at Li
x
La(1-x)/3Nb1-y
Ta
y
O3 (x = 0.1, y = 0.2) stoichiometric composition, and mixed with ethanol. The mixed powder was calcined at 800 °C for 2 hours in air. The calcined powder was grounded and calcined again at 1200°C for 12 hours in air. The calcined powder was then shaped into a cylindrical shape by rubber pressing and sintered at 1350°C for 5 hours in air. Solvent of 5 mol% of La(Nb,Ta)3O9-poor, La(Nb0.5Ta0.5)O4-poor or La(Nb0.8Ta0.2)O4-poor composition relative to the stoichiometric composition of LLNT feeds was prepared using the same procedure as the feed rod preparation. The optical floating zone machine was used for crystal growth. The growth conditions were the growth rate of 2 or 5 mm/h, the growth atmosphere of Ar or N2. The grown crystals were characterized using X-ray diffraction, electron probe micro-analyzer (EPMA), and impedance measurements.

As a result of crystal growth of LLNT by the floating zone (FZ) method, the La(Nb,Ta)3O9 phase was deposited as an inclusion in the initial growth region, even though Li evaporation from the molten zone was not observed. This result indicates that LLNT is an incongruently melting compound. Next, the TSFZ method, FZ method using solvents, was applied to the growth of LLNT crystals. La(Nb,Ta)O4 inclusion phase deposited in the initial growth part of the grown crystal when using solvent of 5 mol% La(Nb,Ta)3O9-poor composition relative to the stoichiometric LLNT. In the case of using a 5 mol% La(Nb0.8Ta0.2)O4-poor solvent composition, crystals with a length of 12 mm and a diameter of 5 mm were obtained as shown in Fig. 1(a). La(Nb,Ta)O4 inclusion phase was not detected in the grown crystal. The chemical composition of the LLNT phase was determined to be y = 0.14-0.25 by quantitative analysis using EPMA as shown in Fig. 1(b). Therefore, inclusion-free LLNT crystals were obtained using a solvent with 5 mol% La(Nb0.8Ta0.2)O4-poor composition relative to the stoichiometric LLNT composition. Moreover, the molten zone was stable in Ar gas or N2 gas flow at growth rate of 5 mm/h. The ionic conductivity of the grown crystal was σ= 2.0 ×10-5 S/cm . The low conductivity is due to cracks, and inhomogeneous in the grown LLNT crystal. Optimization of the solvent composition is required for LLNT crystals with homogeneous and high ionic conductivity.

References.

[1]Y. Maruyama, et. al., J. Ceram. Soc. Jpn. 128, 761-765 (2020). [2]Y. Maruyama, et. al., J. Ceram. Soc. Jpn. 129, 535-539 (2021).

Figure 1