All-solid-state Lithium-ion Batteries Research Articles

Strategies for Enhancing the Stability of Lithium Metal Anodes in Solid-State Electrolytes.

The current commercially used anode material, graphite, has a theoretical capacity of only 372 mAh/g, leading to a relatively low energy density. Lithium (Li) metal is a promising candidate as an anode for enhancing energy density; however, challenges related to safety and performance arise due to Li's dendritic growth, which needs to be addressed. Owing to these critical issues in Li metal batteries, all-solid-state lithium-ion batteries (ASSLIBs) have attracted considerable interest due to their superior energy density and enhanced safety features. Among the key components of ASSLIBs, solid-state electrolytes (SSEs) play a vital role in determining their overall performance. Various types of SSEs, including sulfides, oxides, and polymers, have been extensively investigated for Li metal anodes. Sulfide SSEs have demonstrated high ion conductivity; however, dendrite formation and a limited electrochemical window hinder the commercialization of ASSLIBs due to safety concerns. Conversely, oxide SSEs exhibit a wide electrochemical window, but compatibility issues with Li metal lead to interfacial resistance problems. Polymer SSEs have the advantage of flexibility; however their limited ion conductivity poses challenges for commercialization. This review aims to provide an overview of the distinctive characteristics and inherent challenges associated with each SSE type for Li metal anodes while also proposing potential pathways for future enhancements based on prior research findings.

Interfacial self-healing polymer electrolytes for Long-Cycle silicon anodes in High-Performance solid-state lithium batteries

For all-solid-state lithium-ion batteries (ASSLIBs), silicon (Si) stands out as an appealing anodes material due to its high energy density and improved safety compared to lithium metal. However, the substantial volume changes during cycling result in poor solid-state physical contact and electrolyte–electrode interface issues, leading to unsatisfactory electrochemical performance. In this study, we employed in-situ polymerization to construct an integrated Si anodes/self-healing polymer electrolyte for ASSLIBs. The polymer chain reorganization stems from numerous dynamic bonds in the constructed self-healing dynamic supermolecular elastomer electrolyte (SHDSE) molecular structure. Notably, SHDSE also serves as a Si anodes binder with enhanced adhesive capability. As a result, the well-structured Li|SHDSE|Si-SHDSE cell generates subtle electrolyte–electrode interface contacts at the molecular level, which can offer a continuous and stable Li+ transport pathway, reduce Si particle displacement, and mitigate electrode volume expansion. This further enhances cyclic stability (>500 cycles with 68.1 % capacity retention and >99.8 % Coulombic efficiency). More practically, the 2.0 Ah wave-shaped Si||LiCoO2 soft-pack battery with in-situ cured SHDSE exhibits strongly stabilized electrochemical performance (1.68 Ah after 700 cycles, 86.2 % capacity retention) in spite of a high operating temperatures up to 100 °C and in various bending tests. This represents a groundbreaking report in flexible solid-state soft-pack batteries containing Si anodes.

Influence Mechanism of Interfacial Oxidation of Li3YCl6 Solid Electrolyte on Reduction Potential.

Halide-based solid electrolytes are promising candidates for all solid-state lithium-ion batteries (ASSLBs) due to their high ionic conductivity, wide electrochemical window, and excellent chemical stability with cathode materials. However, when tested in practice, their intrinsic electrochemical stability windows do not well match the conditions for stable operation of ASSBs. Existing literature reports halide-based ASSBs that still operate well outside the electrochemical stability window, while ASSBs that do not operate within the window are not well studied or the studies are based on the cathode material interface. In this study, we aim to elucidate the mechanism behind all-solid-state battery failure by investigating how the reduction potential of Li3YCl6 solid-state electrolyte itself changes under overcharging conditions. Our findings demonstrate that in Li-In|Li3YCl6|Li3YCl6-C half-cells during the first state of charge, Cl ions participate in charge compensation, resulting in a depletion of ligands. This phenomenon significantly affects the reduction potential of Y3+, causing it to be reduced to Y2Cl3 and ultimately to Y0 at conditions far exceeding its actual reduction potential. Furthermore, we analyze the interfacial impedance induced by this process and propose a novel perspective on battery failure.

Enhanced High-Temperature Cycling Stability of Garnet-Based All Solid-State Lithium Battery Using a Multi-Functional Catholyte Buffer Layer

HighlightsThermally stable catholyte buffer layer was fabricated via incorporating a multi-functional flame-retardant triphenyl phosphate additive into poly(ethylene oxide).The optimized catholyte buffer layer enabled thermal and electrochemical stability at interface level, delivering comparable cycling stability of garnet-based all solid-state lithium battery, i.e., capacity retention of 98.5% after 100 cycles at 60 °C, and 89.6% after 50 cycles at 80 °C.Exceptional safety performances were demonstrated, i.e., safely cycling behavior at temperature up to 100 °C and spontaneous fire-extinguishing ability.

A Perspective on the Requirements of Ni‐rich Cathode Surface Modifications for Application in Lithium‐ion Batteries and All‐Solid‐State Lithium‐ion Batteries

AbstractThe increasing adoption of Ni‐rich cathode active materials in commercial liquid electrolyte Lithium‐ion batteries (LIBs) is testament to the improvements in the cathode stability through various surface modification strategies. The development of a deeper understanding of the cathode/electrolyte interface in LIBs has resulted in coatings capable of mitigating both surface and bulk cathode degradation mechanisms. However, due to increasing demands for safe and high energy density cells, a large portion of the research has now shifted towards applying Ni‐rich cathode active materials in inherently safer all‐solid‐state Lithium‐ion batteries (ASSLBs), with the resulting cathode surface modification strategies evolving differently. In this regard, a review outlining the surface modification strategies of Ni‐rich cathode materials applied in both LIB and ASSLB systems is provided. Within, a review of the traditional, advanced and specialized surface modification strategies of each system is discussed, along with a final perspective on the likely future direction of research regarding the design of system‐specific Ni‐rich cathode‐based surface modification strategies.

Multi-strategies interface and structure design of Li- and Mn-rich layered oxide for all-solid-state lithium batteries

Li- and Mn-rich layered oxide (LMRO) cathode materials is highly potential for next generation lithium-ion batteries as its extremely high energy density. However, the oxygen release and the interfacial side reactions against liquid electrolytes cause severe capacity fading and their practical applications are highly impeded. Herein, all-solid-state lithium-ion batteries (ASSLIBs) are demonstrated to be a promising solution towards practical application of LMROs. For the sulfide electrolyte of Li6PS5Cl, a highly compatible interface of LMRO to the electrolyte can be constructed with extra content of Li2MnO3 in LMRO, which prevents significantly side reaction between the LMRO and electrolyte. Moreover, the Li6PS5Cl electrolyte can provide S2-/SO32- redox couple to suppress the oxygen release of LMROs. Combining a further modification in composition with a few amounts of the LiNiO2, the ionic and electronic conductivities of LMRO are evidently improved, where the highly compatible interface is preserved. As results, a superiorly high capacity of 256 mAh g−1 and an energy density of 874 Wh kg−1 at 0.1 C, meanwhile the superior capacity retention as high as 87% for 1000 cycles at 0.5 C are achieved for ASSLIBs. The result is hopefully of great helpful on realizing the practical applications of LMROs in sulfide-based ASSLIBs.

Computational discovery of superior vanadium-niobate-based cathode materials for next-generation all-solid-state lithium-ion battery applications

A high-throughput computational workflow based on first-principles density functional theory calculations is developed for the discovery of novel cathode materials for next-generation all-solid-state lithium-ion battery applications.

Correlation between the particle size of Li1.3Al0.3Ti1.7(PO4)3 solid electrolyte and lithium-ion transport in composite cathodes for all-solid-state lithium-ion batteries

Solid electrolytes (SEs) are key materials for all-solid-state lithium-ion batteries (ASSLBs), and are being studied for various applications. Li1.3Al0.3Ti1.7(PO4)3 (LATP), a NASICON-type SE, is noteworthy due to its wide voltage range for cathode operation and economic feasibility. However, fabricating well-contacted interparticle interfaces in composite cathodes using LATP is challenging because of its high grain-boundary resistance. To address this issue, we investigated the correlation between lithium-ion transport in composite cathodes and the particle size of LATP. We successfully synthesized two LATPs with different size distributions and prepared composite cathodes. Performance evaluation and various advanced analyses of composite cathodes were conducted, the results revealed that LATP with a smaller particle-size distribution formed more a uniform Li+ transfer network in the composite cathode than the larger particles, which contributed to the stable and fast electrochemical characteristics of the ASSLB. Additionally, we also observed real-time structural changes during electrochemical reactions in composite cathodes through in situ X-ray diffraction analysis. The results of our comprehensive analysis are expected to provide valuable insights into the reaction mechanisms of LATP-based ASSLBs, as they have not been extensively explored before.

High-capacity all-solid-state Li-ion battery using MOF-derived carbon-encapsulated iron phosphide as anode material

Iron Phosphide (Fe2P) particles embedded within in-situ generated tubular carbon structures uniformly doped with nitrogen heteroatoms (Fe2P @ NC) have been investigated as an anode in all-solid-state lithium-ion batteries (ASSLIBs). The designed morphology offered a number of suitable features, such as high conductivity, robust framework, and abundant redox active sites for augmenting overall battery performance. As anode, Fe2P @ NC has provided a high lithiation/delithiation capacity of 1214.8 mA h/g /1367.01 mA h/g at a current density of 66.6 mA/g (100 μA) with a high coulombic efficiency (>100%). Further, Fe2P @ NC also demonstrated an excellent rate performance and moderate structural stability during cycling. The charge storing mechanism for Fe2P @ NC investigated via ex-situ X-ray diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS) studies indicates irreversible conversion of Fe2P → Li3P & Fe in the initial cycle and reversible Li3P ↔ LiP reaction in subsequent cycles. Analysis of reaction kinetics for Fe2P @ NC nanocomposite is carried out using CV measurements at different scan rates. This study explores the possibility of MOF-derived iron-phosphide-based composite material as a high-performance anode for ASSLIBs.

Analyzing the Effect of Nano-Sized Conductive Additive Content on Cathode Electrode Performance in Sulfide All-Solid-State Lithium-Ion Batteries

All-solid-state lithium-ion batteries (ASSLBs) have recently received significant attention due to their exceptional energy/power densities, inherent safety, and long-term electrochemical stability. However, to achieve energy- and power-dense ASSLBs, the cathode composite electrodes require optimum ionic and electrical pathways and hence the development of electrode designs that facilitate such requirements is necessary. Among the various available conductive materials, carbon black (CB) is typically considered as a suitable carbon additive for enhancing electrode conductivity due to its affordable price and electrical-network-enhancing properties. In this study, we examined the effect of different weight percentages (wt%) of nano-sized CB as a conductive additive within a cathode composite made up of Ni-rich cathode material (LiNi0.8Co0.1Mn0.1O2) and solid electrolyte (Li6PS5Cl). Composites including 3 wt%, 5 wt%, and 7 wt% CB were produced, achieving capacity retentions of 66.1%, 65.4%, and 44.6% over 50 cycles at 0.5 C. Despite an increase in electrical conductivity of the 7 wt% CB sample, a significantly lower capacity retention was observed. This was attributed to the increased resistance at the solid electrolyte/cathode material interface, resulting from the presence of excessive CB. This study confirms that an excessive amount of nano-sized conductive material can affect the interfacial resistance between the solid electrolyte and the cathode active material, which is ultimately more important to the electrochemical performance than the electrical pathways.

(Invited) Investigating Microstructural Effects of Composite NCM811 Cathodes on ALL-Solid-State Li-Ion Batteries Performance Under Low Operation Stacking Pressure

All-solid-state lithium-ion batteries (ASSLIBs) have been considered suitable alternatives to commercial lithium-ion batteries (LIBs) in the aspect of safety issues that come from the use of inflammable solid electrolytes to replace organic flammable electrolytes. Nevertheless, there apparently remains much room for a better understanding of their properties and behaviors in order to upgrade their performance to reach the practical application level. Ni-rich layered oxides, LiNi1-x-yCoxMnyO2 (NCM), are promising cathodes for high-energy ASSLIBs because of their high capacities and redox potentials, and low material cost when compared with conventional LiCoO2. However, certain challenges associated with their use in ASSLIBs must be addressed for their effective use and industrialization. In particular, the structural integrity of the NCM electrodes during the long-term charge/discharge process suffers from the formation of an intergranular and/or intragranular cracking behavior. These microcracks are initiated at the grain boundaries from the anisotropic chemical strain of the randomly oriented polycrystal (PC) primary cathode particles. Solid evidence behind the electrochem-mechanical breakdown of an NCM cathode with liquid electrolytes has been well discussed and reported in the literature. However, the breakdown in ASSLIBs may not obey as same as in the liquid-electrolyte LIBs and display exclusive mechanics-oriented material damage in the presence of rigid solid-state electrolytes (SSEs). The primary objective of this research is to gain a deeper understanding of various cracking modes in ASSLIBs, which we believe is instrumental to improving the lifespan and cell performance as a whole. ForASSLIBs, stacking pressures greater than 100 MPa under battery operation are currently commonly used. The use of high stacking pressure increases manufacturing and usage difficulties and overall cost. Lowering the battery-operation stacking pressure, for example to the level of the liquid-electrolyte batteries, will certainly facilitate the wider applications of ASSLIBs. In this context, composite cathodes consisting of a LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode and brittle Li3InCl6 (LIC) SSE have been assessed for ASSLIB applications under low operation stacking pressure (coin-cell configuration; ~2.0 MPa). The study reveals the effects of material and structural characteristics of the composite cathode, including the NCM particle size and size distribution, active-material spatial distribution, particle crystallinity (polycrystal or single-crystal), and electrochemical operation parameters (voltage range, current rates) on the cycle stability of the ASSLIBs as a result of the electrochem-mechanical behaviors of the oxide cathode. Meanwhile, a novel solvent-based synthesis process of LIC for achieving high-density cathodes is introduced.

Regulating Ceramic-Polymer Interphase in Composite Solid Electrolytes

Exhibiting satisfactory safety and high energy density, all-solid-state lithium-ion batteries (ASSLBs) is considered as the next-generation energy storage device for green power. Composite solid electrolytes (CSEs) consisting of polymer matrix and active inorganic fillers have shown great potential for practical applications owing to desirable mechanical properties and improved ionic conductivity. However, mechanisms of how different active fillers enhance the ion transport in CSEs still remain inconclusive and comprehensive properties of CSEs need to be improved to meet the demand for high-performance ASSLBs. Our work focuses on the mechanism of Li ion transportation in CSEs and the interaction among polymer matrix, inorganic active fillers and Li-salts. Further, the specific insights into the improving mechanism are applied to the design of CSEs with ideal overall performance.First, NASICON-type (LATP) and garnet-type (LLZTO) inorganic solid electrolytes are utilized as active fillers to incorporate with poly (ethylene oxide) PEO matrix. The experimental and computational results shown that the high affinity between LATP and PEO facilitates unhindered interfacial Li+ transfer, so that LATP functions as bulk-active filler to provide additional inorganic ion pathway. Instead, anion-trapping LLZTO mainly improves the ion conductivity by dissociating lithium salt, making it an interface-active filler. Therefore, the as-prepared PEO-LATP CSEs achieve the highest ion conductivity with medium filler content (50wt%) due to the well-built synergistic ion transport tunnels. By contrast, PEO-LLZTO peak at low filler content (10wt%) attributed to the maximized interfacial interactions.Next, based on the above findings, surface defects are introduced to interface-active LLZTO to not only enhance the anion-trapping effect, but also serve as anchoring points for polymer chains, forming a firmly bonded polymer-ceramic interface. The as-prepared OV-LLZTO/PEO composite exhibits high mechanical strength, reduced interfacial resistance with electrodes as well as improved Li+ conductivity.Further, Li-salt combination in CESs is optimized to improve the electrode compatibility for higher energy density. With the interaction of interface-active LLZTO and main lithium salt, functional additive has access to more preferable coordination. As a result, robust inorganic-rich electrode/electrolyte interface with high ionic conductivity can be synergistically constructed. More importantly, stable and fast ion transport network is built inside the high-volt LCO cathode, thus high rate performance and high capacity retentions achieved in Li|PEO-LLZTO|LCO cells with charging cut-off of 4.2 V.To summarize, we have first revealed ion conduction mechanisms in CSEs, then optimization approaches such as surface defects introduction on the active fillers and Li-salt modification are employed to improve the critical properties of CSE (e.g. ionic conductivity, mechanical strength, interfacial contact and interfacial stability between electrode and electrolyte). These works jointly point out a new principle for the design of high-performance CSEs via regulating the ceramic-polymer interphases. Figure 1

Analysis of Ni-Rich Cathode Composite Electrode Performance According to the Conductive Additive Distribution for Application in Sulfide All-Solid-State Lithium-Ion Batteries

All-solid-state lithium-ion batteries (ASSLBs) represent a promising breakthrough in battery technology owing to their high energy density and exceptional stability. When crafting cathode electrodes for ASSLBs, the solid electrolyte/cathode material interface is physically hindered by the specific morphology of carbon additive materials. In this paper, we examine the distribution of conductive additives within the electrode and its impact on the electrochemical performance of composites incorporating either nano-sized carbon black (CB) or micron-sized carbon nanofibers (CNF) into Ni-rich (LiNi0.8Co0.1Mn0.1O2) cathode material based composites. When nano-sized CB is employed as a conductive additive, it enhances the electrical conductivity of the composite by adopting a uniform distribution. However, its positioning between the solid electrolyte and cathode material leads to an increase in interfacial resistance during charge and discharge cycles, resulting in decreased electrochemical performance. In contrast, using micron-sized CNF as a conductive additive results in a reduction in the composite’s electrical conductivity compared to CB. Nevertheless, due to the comparatively uninterrupted interfaces between the solid electrolyte and cathode materials, it exhibits superior electrochemical characteristics. Our findings are expected to aid the fabrication of electrochemical-enhanced cathode composite electrodes for ASSLBs.

Reducing Gases Triggered Cathode Surface Reconstruction for Stable Cathode-Electrolyte Interface in Practical All-Solid-State Lithium Batteries.

The interfacial compatibility between cathodes and sulfide solid-electrolytes (SEs) is a critical limiting factor of electrochemical performance in all-solid-state lithium-ion batteries (ASSLBs). This work presents a gas-solid interface reduction reaction (GSIRR), aiming to mitigate the reactivity of surface oxygen by inducing a surface reconstruction layer (SRL) . The application of a SRL, CoO/Li2 CO3 , onto LiCoO2 (LCO) cathode results in impressive outcomes, including high capacity (149.7 mAh g-1 ), remarkable cyclability (retention of 84.63% over 400 cycles at 0.2 C), outstanding rate capability (86.1 mAh g-1 at 2 C), and exceptional stability in high-loading cathode (28.97 and 23.45mg cm-2 ) within ASSLBs. Furthermore, the SRL CoO/Li2 CO3 enhances the interfacial stability between LCO and Li10 GeP2 S12 as well as Li3 PS4 SEs. Significantly, the experiments suggest that the GSIRR mechanism can be broadly applied, not only to LCO cathodes but also to LiNi0.8 Co0.1 Mn0.1 O2 cathodes and other reducing gases such as H2 S and CO, indicating its practical universality. This study highlights the significant influence of the surface chemistry of the oxide cathode on interfacial compatibility, and introduces a surface reconstruction strategy based on the GSIRR process as a promising avenue for designing enhanced ASSLBs.

The Effect of Conductive Additive Morphology and Crystallinity on the Electrochemical Performance of Ni-Rich Cathodes for Sulfide All-Solid-State Lithium-Ion Batteries

Sulfide electrolyte all-solid-state lithium-ion batteries (ASSLBs) that have inherently nonflammable properties have improved greatly over the past decade. However, determining both the stable and functional electrode components to pair with these solid electrolytes requires significant investigation. Solid electrolyte comprises 20–40% of the composite cathode electrode, which improves the ionic conductivity. However, this results in thick electrolyte that blocks the electron pathways in the electrode, significantly lowering the electrochemical performance. The application of conductive carbon material is required to overcome this issue, and, hence, determining the carbon properties that result in the most stable performance in the sulfide solid electrolyte is vital. This study analyzes the effect of the cathode conductive additive’s morphology on the electrochemical performance of sulfide electrolyte-based ASSLBs. Carbon black (CB) and carbon nanotubes (CNTs), which provide electron pathways at the nanoscale and sub-micron scale, and carbon nanofiber (CNF), which provides electron pathways at the tens-of-microns scale, are all tested individually as potential conductive additives. When the CNF, with its high crystallinity, is used as a conductive material, the electrochemical performance shows an excellent initial discharge capacity of 191.78 mAh/g and a 50-cycle capacity retention of 83.9%. Conversely, the CB and the CNTs, with their shorter pathways and significantly increased surface area, show a relatively low electrochemical performance. By using the CNF to provide excellent electrical conductivity to the electrode, the polarization is suppressed. Furthermore, the interfacial impedance across the charge transfer region is also reduced over 50 cycles compared with the CB and CNT composite cells. These findings stringently analyze and emphasize the importance of the morphology of the carbon conductive additives in the ASSLB cathode electrodes, with improvements in the electrochemical performance being realized through the application of long-form two-dimensional crystalline CNFs.

Electrothermal model of all‐solid‐state lithium battery with composite solid‐state electrolyte

AbstractFor secondary batteries, thermal runaway has become the main issue, and how to solve it is full of challenges. In this work, a universal thermal model for lithium ion batteries (LIBs) was proposed, which was validated by using commercially available 18650 batteries as well as testing the electrochemical parameters of a Poly(ethylene oxide)(PEO)–bis(trifluoromethane)sulfonimide lithium salt(LiTFSI)–Li2MnO3(LMO) (PLL) composite solid‐state electrolyte (CSSE), while a computational model was developed for all‐solid‐state LIBs (ASSLIBs) based on PLL CSSE. The simulation results show that the maximum temperature of ASSLIBs based on PLL CSSE and commercial standards are both significantly lower than the thermal runaway temperature of solid‐state electrolyte. However, as the temperature of the battery varies greatly under different operating conditions, it will cause great difficulties in the control of other ancillary components and even finally lead to certain safety issues. Therefore, from the perspective of performance and practical application, the CSSE should be improved toward improving the ionic conductivity at low temperatures to have more commercial prospects, and lower interfacial impedance and a higher lithium ion migration number would also be beneficial for optimizing the thermal behavior of ASSLIBs to achieve better commercial prospects.

In Situ and Low-Cost Improvement of the Lithium Anode Interface in Garnet-Type Solid-State Electrolytes.

In recent years, the development of electric vehicles and environmental concerns have made necessary improvements in the energy density and safety of lithium-ion batteries. Therefore, the development of all-solid-state lithium-ion batteries (ASSLIBs) has become imperative. One advantage of ASSLIBs is their potential for downsizing with the use of lithium metal as the anode. However, in this study, a garnet-type solid electrolyte (Li6.75La3Zr1.75Ta0.25O12) was used, which has low reactivity with lithium metal. Thus, interface modification using CaCl2 was employed to form a Li-Ca-Cl composite anode. The interfacial resistance was remarkably reduced to 7 Ω cm2, and the symmetric cell exhibited stable cycling for 1200 h at room temperature and a current density of 0.1 mA cm-2. The voltage ranged from ±15 to ±16 mV. The full cell demonstrated a high initial discharge capacity of 149.2 mA h g-1 and a Coulombic efficiency of 98.0% while maintaining a discharge capacity retention of 91.3% after 100 cycles. These findings lay a solid foundation for future commercial applications as interface modification was achieved through a simple spin-coating process using low-cost CaCl2 (0.7 USD g-1).

Enhanced electrochemistry stability of oxygen doped Li6PS5Cl argyrodite solid electrolyte by liquid-phase synthesis

The argyrodite solid electrolyte Li6PS5Cl is one of the promising candidates due to its high Li-ion conductivity for the application of all-solid-state lithium-ion batteries (ASSLIBs). Unfortunately, Li6PS5Cl argyrodite exhibits low stability against lithium metal anodes and oxide cathodes. One way to improve stability is by oxygen doping into Li6PS5Cl argyrodite. In this work, Li6PS5–2.5xO2.5xCl (x = 0, 0.05, and 0.10) solid electrolytes with oxygen doping were successfully synthesized using liquid-phase synthesis for the first time. Therefore, the solid electrolyte with x = 0.05 exhibits high ionic conductivity with enhanced electrochemical stability against lithium metal and oxide cathodes. Argyrodites with x = 0.05 and x = 0.10 show superior capacity retention and higher Coulomb efficiency compared to x = 0. Moreover, the solid electrolytes also demonstrate better stability during Li symmetrical cell measurements. This experiment provides a controllable amount of oxygen doping into the Li6PS5Cl argyrodite solid electrolyte system in order to achieve high performance of ASSLIBs through liquid-phase synthesis.

Motif-Based Exploration of Halide Classes of Li5M10.5M20.5X8 Conductors Using the DFT Method: Toward High Li-Ion Conductivity and Improved Stability.

The development of all-solid-state lithium-ion batteries (ASSLIBs) is highly dependent on solid-state electrolyte (SSEs) performance. However, current SSEs cannot satisfactorily meet the requirements for high interfacial stability and Li-ion conductivity, especially under high-voltage cycling conditions. To overcome the intractable problems, we theoretically develop the chemistry of structural units to build a series of MX6-unit mixed framework Li5M10.5M20.5X8 (total 184 halides) for use as SSEs and recommend six halide candidates that combine the (electro)chemical stability with a low Li-ion migration barrier. Among them, three Li5M10.5M20.5F8 compounds (M1 = Ca and Mg; M2 = Ti and Zr) exhibit expansive electrochemical windows with a high cathodic limit (6.3 V vs μLi) and three-dimensional Li diffusion associated with moderate Li-migration barriers. To discuss their stability and compatibility (and in turn as a reference for experiments), the energy above the convex hull, the electrochemical stability window, the predicted (electro)reaction products, and the calculated reaction energies of Li5M10.5M20.5X8 in combination with Li-metal and several cathodes are tabulated. We stress that the importance of the cation-mixed effect and specific moieties for the halide anion leads to a design principle for a halide class of Li-ion SSEs. We provide insight into selecting the optimal halide anion and cations and open a new avenue of broad compositional spaces for stable Li-ion SSEs.

Composite Solid Electrolyte Composed of 3D Ceramic Ion Transport Channel and in-Situ Formed Polymer Matrix

Rechargeable lithium-ion batteries (LIBs) with high energy density and excellent cycling performance have been widely used as portable power supplies for consumer electronics. In recent years, LIBs have expanded their applications to electric vehicles (EVs) and large energy storage systems (ESSs). Existing LIBs use liquid electrolytes, which have safety issues such as inflammability, leakage, and explosion. All-solid-state lithium-ion batteries (ASSLIBs) using various solid electrolytes, such as inorganic electrolytes and polymer electrolytes, have been extensively studied to alleviate safety issues and improve energy density. In addition, composite solid electrolytes (CSEs), which combine the advantages of ceramic and polymer electrolytes, are of particular interest. However, CSE based on a polymer matrix has low ionic conductivity at room temperature, making it difficult to use as an electrolyte for high-performance ASSLIB. In this study, we designed a highly efficient 3D LAGP framework for lithium ion transport that enhances the overall conductivity of CSE. This stiffer 3D LAGP structure also inhibits the growth of Li dendrites. The polymer component of CSE is manufactured using thermal polymerization of vinyl ethylene carbonate (VEC). In addition, excellent electrode-electrolyte interface properties were achieved using in-situ thermal polymerization technology. The optimized CSE exhibited high ionic conductivity of 0.79 mS cm-1 and excellent potential stability up to 5.09 V vs. Li/Li+ at 30 °C. The Li/CSE/NCM811 cells showed excellent rate performance and cycling potential. Therefore, a CSE composed of a 3D LAGP framework and a VEC-based polymer can be used as a potential electrolyte for ASSLIBs.