Inorganic Solid-state Electrolytes Research Articles

Rapid Mining of Fast Ion Conductors via Subgraph Isomorphism Matching.

The rapidly evolving field of inorganic solid-state electrolytes (ISSEs) has been driven in recent years by advances in data-mining techniques, which facilitates the high-throughput computational screening for candidate materials in the databases. The key to the mining process is the selection of critical features that underline the similarity of a material to an existing ISSE. Unfortunately, this selection is generally subjective and frequently under debate. Here we propose a subgraph isomorphism matching method that allows an objective evaluation of the similarity between two compounds according to the topology of the local atomic environment. The matching algorithm has been applied to discover four structure types that are highly analogous to the LiTi2(PO4)3 NASICON prototype. We demonstrate that the local atomic environments similar to LiTi2(PO4)3 endow these four structures with favorable Li diffusion tunnels and ionic conductivity on par with those of the prototype. By further taking into account the electronic structure and electrochemical stability window, 13 compounds are identified to be potential ISSEs. Our findings not only offer a promising approach toward rapid mining of fast ion conductors without limitation in the compositional range but also reveal insights into the design of ISSEs according to the topology of their framework structures.

A Universal Self-Propagating Synthesis of Aluminum-Based Oxyhalide Solid-State Electrolytes.

Inorganic solid-state electrolytes (SSEs) play a vital role in high-energy all-solid-state batteries (ASSBs). However, the current method of SSE preparation usually involves high-energy mechanical ball milling and/or a high-temperature annealing process, which is not suitable for practical application. Here, a facile strategy is developed to realize the scalable synthesis of cost-effective aluminum-based oxyhalide SSEs, which involves a self-propagating method by the exothermic reaction of the raw materials. This strategy enables the synthesis of various aluminum-based oxyhalide SSEs with tunable components and high ionic conductivities (over 10-3 S cm-1 at 25 °C) for different cations (Li+, Na+, Ag+). It is elucidated that the amorphous matrix, which mainly consists of various oxidized chloroaluminate species that provide numerous sites for smooth ion migration, is actually the key factor for the achieved high conductivities. Benefit from their easy synthesis, low cost, and low weight, the aluminum-based oxyhalide SSEs synthesized by our approach could further promote practical application of high-energy-density ASSBs.

Incorporating Sodium-Conductive Polymeric Interfacial Adhesive with Inorganic Solid-State Electrolytes for Quasi-Solid-State Sodium Metal Batteries.

Inorganic solid-state electrolytes have attracted enormous attention due to their potential safety, increased energy density, and long cycle-life benefits. However, their application in solid-state batteries is limited by unstable electrode-electrolyte interface, poor point-to-point physical contact, and low utilization of metallic anodes. Herein, interfacial engineering based on sodium (Na)-conductive polymeric solid-state interfacial adhesive is studied to improve interface stability and optimize physical contacts, constructing a robust organic-rich solid electrolyte interphaselayer to prevent dendrite-induced crack propagation and security issues. The interfacial adhesive strategy significantly increases the room-temperature critical current density of inorganic Na-ion conductors from 0.8 to 3.2mAcm-2 and markedly enhances the cycling performance of solid-state batteries up to 500 cycles, respectively. Particularly, the Na3V2(PO4)3-based full solid-state batteries with high cathode loading of 10.16mgcm-2 also deliver an excellent cycling performance, further realizing the stable operation of solid-state laminated pouch cells. The research provides fundamental perspectives into the role of interfacial chemistry and takes the field a step closer to realizing practical solid-state batteries.

Stable Oxyhalide-Nitride Fast Ionic Conductors for All-Solid-State Li Metal Batteries.

Rechargeable all-solid-state lithium metal batteries (ASSLMBs) utilizing inorganic solid-state electrolytes (SSEs) are promising for electric vehicles and large-scale grid energy storage. However, the Li dendrite growth in SSEs still constrains the practical utility of ASSLMBs. To achieve a high dendrite-suppression capability, SSEs must be chemically stable with Li, possess fast Li transfer kinetics, and exhibit high interface energy. Herein, a class of low-cost, eco-friendly, and sustainable oxyhalide-nitride solid electrolytes (ONSEs), denoted as LixNyIz-qLiOH (where x = 3y + z, 0 ≤ q ≤ 0.75), is designed to fulfill all the requirements. As-prepared ONSEs demonstrate chemically stable against Li and high interface energy (>43.08 meV Å-2), effectively restraining Li dendrite growth and the self-degradation at electrode interfaces. Furthermore, improved thermodynamic oxidation stability of ONSEs (>3V vs Li+/Li, 0.45V for pure Li3N), arising from the increased ionicity of Li─N bonds, contributes to the stability in ASSLMBs. As a proof-of-concept, the optimized ONSEs possess high ionic conductivity of 0.52 mS cm-1 and achieve long-term cycling of Li||Li symmetric cell for over 500h. When coupled with the Li3InCl6 SSE for high-voltage cathodes, the bilayer oxyhalide-nitride/Li3InCl6 electrolyte imparts 90% capacity retention over 500 cycles for Li||1 mAh cm-2 LiCoO2 cells.

Constructing Enhanced Composite Solid-State Electrolytes with Sb/Nb Co-Doped LLZO and PVDF-HFP

Composite solid-state electrolytes are viewed as promising materials for solid-state lithium-ion batteries due to their combined advantages of inorganic solid-state electrolytes and solid-state polymer electrolytes. In this study, the solid electrolytes Li6.7−xLa3Zr1.7−xSb0.3NbxO12 (LLZSNO) with Sb and Nb co-doping were prepared by a high-temperature solid-phase method. Results indicate that Sb/Nb co-doping causes lattice deformation in LLZO and increases the lithium vacancy concentration and conductivity of LLZO. Then, with the co-doped LLZSNO as an inorganic filler, a composite solid electrolyte of polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) was prepared with a casting method. The obtained composite solid electrolyte exhibits a high ionic conductivity of 1.76 × 10−4 S/cm at room temperature, a wide electrochemical stable window of 5.2 V, and a lithium-ion transfer number of 0.32. The Li|LiFePO4 coin battery with the composite solid electrolyte shows a high specific capacity of 161.2 mAh/g and a Coulombic efficiency close to 100% at 1 C. In addition, the symmetrical lithium battery Li|Li with the composite electrolyte could cycle stably for about 1500 h without failure at room temperature.

Computational Design of Inorganic Solid-State Electrolyte Materials for Lithium-Ion Batteries

Computational Design of Inorganic Solid-State Electrolyte Materials for Lithium-Ion Batteries

How Concerted Are Ionic Hops in Inorganic Solid-State Electrolytes?

Despite being fundamental to the understanding of solid-state electrolytes (SSEs), little is known on the degree of coordination between mobile ions in diffusive events, thus hindering a detailed comprehension and possible rational design of SSEs. Here, we introduce an unsupervised k-means clustering approach that is able to identify ion-hopping events and correlations between many mobile ions and apply it to a comprehensive ab initio MD database comprising several families of inorganic SSEs and millions of ionic configurations. It is found that despite two-body interactions between mobile ions being the largest, higher-order n-ion (2 < n) correlations are most frequent. Specifically, we prove a general exponential decaying law for the probability density function governing the number of concerted mobile ions. For the particular case of Li-based SSEs, it is shown that the average number of correlated mobile ions amounts to 10 ± 5 and that this result is practically independent of the temperature. Interestingly, our data-driven analysis reveals that fast-ionic diffusion strongly and positively correlates with ample hopping lengths and long hopping spans but not with high hopping frequencies and short interstitial residence times. Finally, it is shown that neglection of many-ion correlations generally leads to a modest overestimation of the hopping frequency that roughly is proportional to the average number of correlated mobile ions.

NaSbF4 nanoparticles as solid-state electrolytes in sodium-iodine batteries: sodium ion transport via conversion reaction and shuttle effect retarded by fluoride

Na-I2 batteries have emerged as an appealing energy storage technology owing to high energy density and cost-effectiveness. However, the practical application of Na-I2 batteries faces the dissolution of iodide/polyiodide in the electrolyte during the charge/discharge process. Herein, we immobilize I2 by utilization of NaSbF4 (NSF)-based solid-state electrolyte (SSE). Impressively, the Na+ transport in NSF nanoparticles (NPs) is via the conversion reaction of NaSbF4 + NaF ↔ Na2SbF5, which is different from the acknowledged Na+ diffusion mechanism via vacancies in inorganic SSEs. To improve the interfacial compatibility, a composite polymer electrolyte (CPE) is fabricated based on NSF, poly (vinylidene fluoride - hexafuoro -propylene) (PVDF-HFP) and NaClO4, giving rise to stable Na stripping/plating in Na|Na symmetric cell. Especially, the quasi-solid-state Na|NSF CPE |I2 full cell shows an outstanding electrochemical behavior, which is associated with the partial reduction of ClO4− → Cl− and the stabilization of I+ by F− or Cl− in the charge/discharge process. The resultant I+-F- or I+-Cl- intermediate can promote the multi-electron transfer of 2I− → I2 → 2I+, leading to enhanced capacity and mitigated shuttle effect of iodide. Meanwhile, the formation of I+-F- in turn weakens the interaction of Na⋯F in NSF, which is beneficial for Na+ transport.

Enhancement of microstructure and electrochemical properties of LLZTO solid state electrolyte by co-doping with Ga and Y

Recently, there has been strong interest in inorganic solid-state electrolytes for all-solid-state batteries, among which the garnet electrolyte LLZO has attracted much attention due to its excellent properties, such as high ionic conductivity and broad electrochemical stability. The aim of our study was to improve the performance of Ta-doped LLZO (LLZTO) by co-doping Ga and Y at the Li and La sites using conventional solid-phase synthesis methods. We thoroughly investigated how Ga and Y affect the microstructure and electrochemical properties of LLZTO. The results show that the relative density of Ga- and Y-doped LLZTO increases significantly up to 94% under the same sintering conditions. This doping resulted in a significant increase in ionic conductivity from 2.0 × 10−4 S·cm−1 to 1.05 × 10−3 S·cm−1 and a decrease in electronic conductivity from 2.16 × 10−7 S·cm−1 to 9.18 × 10−8 S·cm−1. Subsequently, the symmetric cells were assembled and tested, and it was found that the interfaces of the doped solid-state electrolytes were much more stable and that the cycling time was longer. Thus, our study successfully coordinated the co-doping of Ga, Y, and Ta, providing valuable insights for the subsequent production of LLZO materials with higher densities and better performance. This study is a promising step toward the realization of safer all-solid-state batteries with higher energy densities.

NaSn2F5 nanocluster composed of nanoparticles with matched lattices induced by dislocations: Accelerated sodium-ion transport via in situ oxidation in solid-state sodium metal battery

Na metal batteries using inorganic solid-state electrolytes (SSEs) have attracted extensive attention due to their superior safety and high energy density. However, their development is plagued by the unclear structural/volumetric evolution of SSEs and the corresponding Na+ migration mechanisms. In this work, NaSn2F5 (NSF) clusters are composed of nanoparticles (NPs) with matched lattices induced by dislocations, which can mitigate the volume swelling/shrinkage of the NPs. NSF behaves like a single ion conductor with a high Na+ transference number (tNa+) of 0.79. Specially, the ionic conductivity (σ) of NSF is increased from 7.64 × 10-6 to 5.42 × 10-5 S cm−1 after partial irreversible oxidation of Sn2+ (0.118 Å) → Sn4+ (0.069 Å) with the shrunk ionic radius during the charge process, giving more spaces for Na+ migration. Furthermore, a poly(acrylonitrile)-NaSn2F5-NaPF6 composite polymer electrolyte (NSF CPE) was fabricated with a σ of 4.13 × 10-4 S cm−1 and a tNa+ of 0.60. The NSF CPE-based symmetric cell can operate over 3000 h due to the couplings between the different components in NSF CPE, which is beneficial for ion transfer and the construction of stable solid electrolyte interface. And the quasi-solid-state Na|NSF CPE|Na3V2(PO4)3 full cell displays excellent electrochemical performance.

Chemomechanical Origins of the Dynamic Evolution of Isolated Li Filaments in Inorganic Solid-State Electrolytes.

The penetrating growth of Li into the inorganic solid-state electrolyte (SSE) is one key factor limiting its practical application. Research to understand the underlying mechanism of Li penetration has been ongoing for years and is continuing. Here, we report an in situ scanning electron microscopy methodology to investigate the dynamic behaviors of isolated Li filaments in the garnet SSE under practical cycling conditions. We find that the filaments tend to grow in the SSE, while surprisingly, those filaments can self-dissolve with a decrease in the current density without a reversal of the current direction. We further build a coupled electro-chemo-mechanical model to assess the interplay between electrochemistry and mechanics during the dynamic evolution of filaments. We reveal that filament growth is strongly regulated by the competition between the electrochemical driving force and mechanical resistive force. The numerical results provide rational guidance for the design of solid-state batteries with excellent properties.

Self-assembled hydrated copper coordination compounds as ionic conductors for room temperature solid-state batteries

As the core component of solid-state batteries, neither current inorganic solid-state electrolytes nor solid polymer electrolytes can simultaneously possess satisfactory ionic conductivity, electrode compatibility and processability. By incorporating efficient Li+ diffusion channels found in inorganic solid-state electrolytes and polar functional groups present in solid polymer electrolytes, it is conceivable to design inorganic-organic hybrid solid-state electrolytes to achieve true fusion and synergy in performance. Herein, we demonstrate that traditional metal coordination compounds can serve as exceptional Li+ ion conductors at room temperature through rational structural design. Specifically, we synthesize copper maleate hydrate nanoflakes via bottom-up self-assembly featuring highly-ordered 1D channels that are interconnected by Cu2+/Cu+ nodes and maleic acid ligands, alongside rich COO− groups and structural water within the channels. Benefiting from the combination of ion-hopping and coupling-dissociation mechanisms, Li+ ions can preferably transport through these channels rapidly. Thus, the Li+-implanted copper maleate hydrate solid-state electrolytes shows remarkable ionic conductivity (1.17 × 10−4 S cm−1 at room temperature), high Li+ transference number (0.77), and a 4.7 V-wide operating window. More impressively, Li+-implanted copper maleate hydrate solid-state electrolytes are demonstrated to have exceptional compatibility with both cathode and Li anode, enabling long-term stability of more than 800 cycles. This work brings new insight on exploring superior room-temperature ionic conductors based on metal coordination compounds.

A comprehensive investigation of Ag7P3X11 (X = {O, S, and Se}) solid-state silver superionic conductors

This investigation rigorously analyzes and introduces a new class of high-performance inorganic solid-state electrolytes, formulated as Ag7P3X11 (X = {O, S, Se}), through comprehensive ab initio calculations, highlighting their potential for advanced energy storage technologies.

Spectroscopic and Computational Evaluation of Electrochemical Stability of Electrolyte Solutions; Solvents, Electrolytes and Their Concentration Dependence

Since the introduction of Lithium-ion batteries (LIBs) into commercial use, great improvements have been achieved in their performance such as energy density, durability, and safety. However, there still remain many technical issues to meet the increasing demands for a longer driving range of electric vehicles, a larger storage for renewable energy. Research and development of electrode active materials are extensively progressing to respond those market needs, and R&D for electrolyte solutions are also active in order to utilize the fullest extent of the newly developed electrode materials.Various kinds of characteristics are required for electrolyte solutions in LIBs. Ideally, the electrochemical stability in a wide potential range is needed, but almost all the electrolyte solutions reductively decompose on negative electrodes, and the decomposition products precipitate on the electrode to form a protective surface film, which is referred to as SEI (solid electrolyte interphase). Because the nature of SEI is influenced by chemical structures of electrolyte solutions, the solvents and lithium salts need to be combined properly to realize LIBs with better performance. Although the conventional electrolyte solutions show satisfactory performance to some extent, there still remain some disadvantages; instability against moisture and temperature, and volatility and flammability of carbonate ester solvents. Great efforts have been made to overcome those disadvantages in the conventional electrolyte solutions, for example, utilization of ionic liquid, polymer electrolytes and inorganic solid state electrolytes, and recently, highly concentrated electrolyte solution gathers a lot of attention.Based on these background, solid electrolyte interphase (SEI) formed on graphite in conventional and highly concentrated electrolyte solutions was thoroughly characterized by a combined experimental and computational study. The comprehensive understanding revealed that a chemical composition of SEI, as well as the solvation structures unstable to reductive potential, can be predicted by a profound understanding of density functional theory (DFT) calculation results of the solvates containing a counter anion. The solvation structures were determined by Raman spectroscopy to evaluate electron affinity (EA) and LUMO of the solvates containing an anion by DFT calculation. The chemical composition of SEI was quantitatively analyzed by X-ray photoelectron spectroscopy (XPS), and the results were compared with a prediction based on the calculation. The formation mechanism of SEI during charge and discharge process can be partly estimated by the combination of experiment and theoretical calculation. These results indicate that electrolyte solutions can be efficiently designed by predicting the physicochemical properties of SEI through the more effective utilization of DFT calculation. Thus, a combination of DFT prediction and experimental analysis is proved to be an effective approach to reveal SEI formation mechanisms, and can be utilized as a versatile approach to develop new solvents, electrolyte salts, and additives, and to design electrolyte solutions with appropriate concentration.It is expected that the oxidative stability and reaction mechanism of electrolyte solutions at the positive electrode can be estimated using similar approaches. Here, it is necessary to predict oxidative stability using ionization potentials (IP), rather than EA. In the same way, other solvents than carbonate, such as ethers and sulfones, which have been difficult to put into practical use in conventional electrolytes, can also be the target to be studied. By analyzing the solvation structure and estimating its chemical stability, we believe it will be possible to get many insights on the reactions that proceed at the interface between the electrode and the electrolyte. Figure 1

(Invited) Developing High-Energy All-Solid-State Batteries with Long Cycle Life

While conventional lithium-ion batteries (LIBs) continue to gain progress through incremental improvements, the presence of organic liquid electrolytes brings about fundamental safety issues as their reactivity and flammability subject LIBs to thermal runaway. [1-4] With higher energy densities and better safety performances, all-solid-state batteries (ASSBs) consisting of a 4 V-class cathode active material (CAM), an inorganic solid-state electrolyte (SE) and a lithium-metal anode are considered the future of energy storage technologies. [5-6] The development of practical ASSBs, however, has met a number of challenges. SEs simultaneously meeting the criteria in conductivity, stability and mechanical properties are yet to be discovered. At the anode, reductive degradation of SE, high interfacial impedance and dendrite formation are the most pressing issues. At the cathode, instabilities due to oxidative degradation of SE, reactivities between SE and CAM as well as the loss of mechanical integrity significantly limit ASSB performance.In this presentation, we discuss our recent effort in addressing these challenges, including the development of novel halide SEs, design of composite cathode structure that enables direct use of uncoated-LiNi0.8Co0.1Mn0.1O2 CAM, and implement of Li-metal based anodes that enable better interface with the SE. We demonstrate the excellent long-term cycling performance achieved on such cells and illustrate the underlying working mechanism. [7] The importance in proper matching of cathode, SE and anode properties as well as our views on future development of better-performing ASSB cells will be presented. References Arbizzani, G. Gabrielli and M. Mastragostino, Journal of Power Sources, 2011, 196, 4801-4805.Murmann, R. Schmitz, S. Nowak, N. Ignatiev, P. Sartori, I. Cekic-Laskovic and M. Winter, Journal of The Electrochemical Society, 2015, 162, A1738.Cao, X. Ren, L. Zou, M. H. Engelhard, W. Huang, H. Wang, B. E. Matthews, H. Lee, C. Niu and B. W. Arey, Nature Energy, 2019, 4, 796-805.Fan, L. Chen, O. Borodin, X. Ji, J. Chen, S. Hou, T. Deng, J. Zheng, C. Yang, S.-C. Liou, K. Amine, K. Xu and C. Wang, Nature Nanotechnology, 2018, 13, 715-722.Janek and W. G. J. N. E. Zeier, Nature Energy, 2016, 1, 1-4.Famprikis, P. Canepa, J. A. Dawson, M. S. Islam and C. Masquelier, Nature Materials, 2019, 18, 1278-1291.Y. Kim, H. Cha, R. Kostecki and G. Chen, ACS Energy Letters 2023, 8, 521.

Solid-State Polymer Battery: Manufacturing Process and Characterization

Solid-state batteries are a promising technology that could provide higher energy density, better safety, longer cycle life and a wider operating temperature range than current commercial LiBs [1] .The solid electrolyte is the main component of all-solid-state batteries. It can be ceramic, glass, polymer, or a mixture. Solid Polymer Electrolyte (SPEs) have received distinctive attention, especially by industry, owing to their potential advantages such as safety, lightweight, high flexibility, and realistic processability. However, despite fast growing interest in solid-state technology, reports on the scalable production of all-solid-state lithium-ion batteries using electrodes with meaningful areal capacities are rather scarce [2] . Moreover, chemical, and mechanical challenges remain. The intimate contact between the electrode and the solid electrolyte is difficult due its non-infiltrative nature. This lack of intimate contact severely limits the cycling properties [3] . The development of effective strategies to alleviate the issue of physical contact is imperative in the engineering of solid-state batteries [4] .In the frame of SAFELiMOVE (Advanced all Solid stAte saFE Lithium Metal technology tOwards Vehicle Electrification) project, we assemble a solid-state pouch based on lithium metal anode, a solid polymer electrolyte layer and a compatible cathode. In work, we report on a reliable fabrication process of large-scale all-solid-state lithium-ion batteries using cathodes prepared by CIDETEC, lithium anode provided by Hydro-Quebec, polymers provided by CICe, inorganic filler provided by SCHOTT and a solid polymer electrolyte manufactured at SAFT.All-solid-state lithium-ion battery pouch cells have been successfully built with consistent electrochemical performance. Cycling that shows the good performance of those cells and the lesson learned regarding their cycling conditions will be presented. [1] J. Motalli, “A solid future Nature, 526, S96 (2015) [2] Ningxin Zhang et al “Scalable preparation of practical 1Ah all-solid-state lithium-ion batteries cells and their abuse tests”, Journal of Energy Storage 59 (2023) 106547 [3] Li et al.“Atomically Intimate Contact between Solid Electrolytes and Electrodes for Li Batteries” Mater 1, 1001-1016, October 2, 2019. [4] Theodosios Famprikis, Pieremanuele Canepa, James A. Dawson, M. Saiful Islam and Christian Masquelier“Fundamentals of inorganic solid-state electrolytes for batteries” Nature Materials-August 2019. Figure 1

Advances in Inorganic Solid-State Electrolyte/Li Interface.

The increasing demand for high-energy-density and high-safety energy storage devices has sparked a growing interest in all-solid-state lithium metal batteries (ASSLMBs). A high-quality inorganic solid-state electrolyte (ISE) is a fundamental requirement for ASSLMBs, and an effective ISE/Li interface is a key factor in attaining high-performance ASSLMBs. In this Concept, we initially summarize the challenges encountered by ISE/Li interfaces and delineate four commonly employed strategies for modifying the ISE/Li interface. Then, we explore the merits and drawbacks of coatings utilized as ISE/Li interfacial phases. We also delve into the commonly employed thermal bonding and innovative cold bonding methods utilized for in situ interface preparation. Lastly, we spotlight future directions for enhancing the functionality of ISE/Li interfaces and achieving high-performance ASSLMBs.

Interfacially-enhanced quasi-solid electrolyte using ionic liquid for lithium-ion battery

Solid-state electrolytes (SEs), promising alternatives to liquid electrolytes (LEs), have their own pros and cons, necessitating exploring combined systems to achieve optimal performance. However, several issues occur due to the poor interface between combined SEs. Herein, Li7La3Zr2O12 (LLZO) inorganic SE and PVDF-HFP (poly(vinylidene fluoride-co-hexafluoropropylene)) solid polymer electrolyte are combined with the ionic liquid BMIM-TFSI (1-Butyl-3-methylimidazoliumbis-(trifluoromethylsulfonyl)imide) to obtain quasi-solid electrolyte (QSE) via a facile method. This study reveals that BMIM-TFSI in PVDF-HFP acts as a plasticizer and has an important role in covering LLZO particles for the properly formed interface between inorganic SE particles and solid polymer electrolyte. Thanks to the well-built interface, the QSE exhibits a high Li-ion transference number (tLi+), good ionic conductivity, and outstanding cycling performance, including a high capacity of 140 mAh g− 1 and stable Coulombic efficiency. Therefore, QSE has high potential as a next-generation SE for lithium batteries with its good electrochemical properties and simple fabrication process.

A cost-effective, ionically conductive and compressible oxychloride solid-state electrolyte for stable all-solid-state lithium-based batteries

To enable the development of all-solid-state batteries, an inorganic solid-state electrolyte should demonstrate high ionic conductivity (i.e., > 1 mS cm−1 at 25 °C), compressibility (e.g., > 90% density under 250−350 MPa), and cost-effectiveness (e.g., < $50/kg). Here we report the development and preparation of Li1.75ZrCl4.75O0.5 oxychloride solid-state electrolyte that demonstrates an ionic conductivity of 2.42 mS cm−1 at 25 °C, a compressibility enabling 94.2% density under 300 MPa and an estimated raw materials cost of $11.60/kg. As proof of concept, the Li1.75ZrCl4.75O0.5 is tested in combination with a LiNi0.8Mn0.1Co0.1O2-based positive electrode and a Li6PS5Cl-coated Li-In negative electrode in lab-scale cell configuration. This all-solid-state cell delivers a discharge capacity retention of 70.34% (final discharge capacity of 70.2 mAh g−1) after 2082 cycles at 1 A g−1, 25 °C and 1.5 tons of stacking pressure.

An asymmetric electrolyte to simultaneously meet contradictory requirements of anode and cathode

One of the major obstacles hindering the application of zinc metal batteries is the contradictory demands from the Zn metal anode and cathodes. At the anode side, water induces serious corrosion and dendrite growth, remarkably suppressing the reversibility of Zn plating/stripping. At the cathode side, water is essential because many cathode materials require both H+ and Zn2+ insertion/extraction to achieve a high capacity and long lifespan. Herein, an asymmetric design of inorganic solid-state electrolyte combined with hydrogel electrolyte is presented to simultaneously meet the as-mentioned contrary requirements. The inorganic solid-state electrolyte is toward the Zn anode to realize a dendrite-free and corrosion-free highly reversible Zn plating/stripping, and the hydrogel electrolyte enables consequent H+ and Zn2+ insertion/extraction at the cathode side for high performance. Therefore, there is no hydrogen and dendrite growth detected in cells with a super high-areal-capacity up to 10 mAh·cm−2 (Zn//Zn), ~5.5 mAh·cm−2 (Zn//MnO2) and ~7.2 mAh·cm−2 (Zn//V2O5). These Zn//MnO2 and Zn//V2O5 batteries show remarkable cycling stability over 1000 cycles with 92.4% and over 400 cycles with 90.5% initial capacity retained, respectively.