Garnet Oxide Research Articles

Enhanced Critical Current Density in the Garnet Oxide Electrolyte by a Silver Interlayer.

Ta-doped Li6.4La3Zr1.4Ta0.6O12 (LLZTO) for solid-state lithium batteries demonstrates encouraging performance; however, they encounter issues with lithium dendrite formation that impede their widespread use. Herein, we design a LLZTO ceramic with an interlayer containing a mixed dense layer of Ag and LLZTO, prepared by one-step sintering. The Ag-rich interlayer in LLZTO can hinder the growth and the penetration of lithium dendrites though the reaction between Ag and lithium metal. Compared with the Ag-free counterpart, a higher critical current density of 0.6 mA cm-2, in addition to a longer life span under a current density of 0.2 mA cm-2, is achieved by adopting the interlayer in LLZTO. This research offers novel insights into the engineering of garnet-based solid electrolytes, tailored for the advancement of high-rate lithium metal batteries.

Garnet and Li29Zr9Nb3O40 Modified PEO‐Based Hybrid Solid Electrolytes for All‐Solid‐State Lithium Metal Batteries

AbstractInorganic‐organic hybrid solid electrolytes (HSEs) are an important category of electrolyte materials for solid‐state batterie. It is of interest and importance to investigate the influence of composition and content of inorganic fillers on the electrochemical performance of HSEs. In this paper, we fabricated HSEs using polyethylene oxide (PEO) as matrix and incorporating different inorganic powders as active fillers. A series of HSEs with different contents of Ga/Nb co‐substituted garnet oxide (Li6.35Ga0.15La3Zr1.8Nb0.2O12, GN‐LLZO) and Y‐doped Li29Zr9Nb3O40 (Li29.3Zr8.7Y0.3Nb3O40, 0.3Y‐LZNO) were carefully designed. The ionic conductivity of these PEO‐based HSEs were studied, and their performance in solid‐state lithium‐ion batteries with LiFePO4 (LFP) as cathode material and Li metal as anode were evaluated. The results showed that the HSE with addition content of inorganic powders, namely PEOLiTFSI@5 % GN‐LLZO +5 %0.3Y‐LZNO (noted as PL3) showed the optimized ionic conductivity of 2.9×10−4 S cm−1 at room temperature with an activation energy Ea of 0.21 eV. It has an electrochemical stability window of 4.65 V and ionic transfer number of 0.242. The addition of inorganic powders not only enhanced the ionic conductivities of PEO‐based HSEs, but also exhibited superior stability and interfacial compatibility with electrodes, leading to the improved cycle stability in the LFP/PL3/Li solid‐state battery configuration.

An electron-blocking interface for garnet-based quasi-solid-state lithium-metal batteries to improve lifespan

Garnet oxide is one of the most promising solid electrolytes for solid-state lithium metal batteries. However, the traditional interface modification layers cannot completely block electron migrating from the current collector to the interior of the solid-state electrolyte, which promotes the penetration of lithium dendrites. In this work, a highly electron-blocking interlayer composed of potassium fluoride (KF) is deposited on garnet oxide Li6.4La3Zr1.4Ta0.6O12 (LLZTO). After reacting with melted lithium metal, KF in-situ transforms to KF/LiF interlayer, which can block the electron leakage and inhibit lithium dendrite growth. The Li symmetric cells using the interlayer show a long cycle life of ~3000 hours at 0.2 mA cm−2 and over 350 hours at 0.5 mA cm−2 respectively. Moreover, an ionic liquid of LiTFSI in C4mim-TFSI is screened to wet the LLZTO|LiNi0.8Co0.1Mn0.1O2 (NCM) positive electrode interfaces. The Li|KF-LLZTO | NCM cells present a specific capacity of 109.3 mAh g−1, long lifespan of 3500 cycles and capacity retention of 72.5% at 25 °C and 2 C (380 mA g−1) with an average coulombic efficiency of 99.99%. This work provides a simple and integrated strategy on high-performance quasi-solid-state lithium metal batteries.

Engineering atomic size mismatch in Pr3+, La3+ codoped Lu3Al5O12 garnet single crystals for tailored structure and functional properties

This study provided the first in-depth investigation of the effects of large dopant incompatibility (Pr3+ and La3+ ions) on the small host lattice element (Lu3+) in Lu3Al5O12 (LuAG) single crystal. The growth of such complex crystals from the melt presented many challenges. By engineering the ionic radius ratio of RE- and M-site cations, a single-crystal phase stabilized by configurational entropy was achieved. This investigation elucidated the crystallization behavior of configurationally disordered rare-earth aluminum garnet oxide (Lu1−x−yPrxLay)3Al5O12 from the melt and characterized its functional properties, including microstructural, optical, photoluminescence, and scintillation properties, between 5 and 300 K. Relaxation of the imposed strain energy led to local perturbations and destabilization of the garnet structure. Multielemental EDS mapping, micro-Raman spectroscopy, and thermoluminescence revealed the mechanism by which atomic size mismatch drove a smooth transition from the garnet to the perovskite phase in high entropy garnets. The optical, photoluminescence, and scintillation measurements provided fundamental insights into property changes driven by incompatibility doping. Standard and modified Judd-Ofelt theory analysis of absorption spectra determined the phenomenological Judd-Ofelt parameters Ωλ and radiative lifetimes. Atomic size mismatch engineering offers a promising approach to overcoming the limitations of conventional eutectic synthesis methods.

Using neutron diffraction to explore lithium displacement within cubic phase stabilised Ga-doped Li6.75La3Zr1.75Ta0.25O12 lithium garnet oxides

Typical Li6.75La3Zr1.75Ta0.25O12 exists as a mixture of tetragonal and cubic arrangements, but adding small amounts of Ga3+ (Li6.75–3xGaxLa3Zr1.75Ta0.25O12 x ≥ 0.1) resulted in a single cubic (I a-3d) phase lithium garnet oxide. Following the stabilisation of the cubic phase, the effects on lithium distributions were explored with neutron powder diffraction concerning Ga3+ content and temperature. Increasing the amount of Ga3+ reduced the amount of lithium within the structure, directly decreasing the Li 96h site occupancy and showing a minimal effect on the Li 24d site occupancy. High-temperature neutron diffraction studies revealed the migration of lithium from the Li 24d site to the Li 96h with increasing temperature. The inclusion of Ga3+ improved the total ionic conductivity over the gallium-free system. However, with increasing gallium content (x > 0.1), a negative correlation between the garnet's gallium content and total lithium ionic conductivity is observed, showing how the total amount of free lithium ions impact the system's total ionic conductivity. Though the electrolytes explored here show some limitations, the lithium-ion displacement trends with doping and temperature give us further insight into how these lithium garnet systems respond to chemical and physical change.

Reactive Magnesium Nitride Additive: A Drop-in Solution for Lithium/Garnet Wetting in All-Solid-State Batteries.

Garnet oxides such as Li6.4 La3 Zr1.4 Ta0.6 O12 (LLZTO) are promising solid electrolyte materials for all-solid-state lithium-metal batteries because of high ionic conductivity, low electronic leakage, and wide electrochemical stability window. While LLZTO has been frequently discussed to be stable against lithium metal anode, it is challenging to achieve and maintain good solid-on-solid wetting at the metal/ceramic interface in both processing and extended electrochemical cycling. Here we address the challenge by a powder-form magnesium nitride additive, which reacts with the lithium metal anode to produce well-dispersed lithium nitride. The in situ formed lithium nitride promotes reactive wetting at the Li/LLZTO interface, which lowers interfacial resistance, increases critical current density (CCD), and improves cycling stability of the electrochemical cells. The additive recipe has been diversified to titanium nitride, zirconium nitride, tantalum nitride, and niobium nitride, thus supporting the general concept of reactive dispersion-plus-wetting. Such a design can be extended to other solid-state devices for better functioning and extended cycle life.

Up-conversion emission in transition metal and lanthanide co-doped systems: dimer sensitization revisited

Lanthanide (Ln) co-doped transition metal (TM) upconversion (UC) co-doped systems are being intensively investigated for their exciting applications in photonics, bioimaging, and luminescence thermometry. The presence of TM, such as Mo6 + /W6 +, Mn2 +, or Fe3 + determines significant changes in Ln UC emission, such as intensity enhancement, colour modulation, and even the alteration of the photon order. The current mechanism assumes a ground-state absorption/excited-state absorption (ESA/GSA) in TM-Yb dimer followed by direct energy transfer to Er/Tm excited states. We revisit this mechanism by addressing two issues that remain ignored: a dynamical approach to the investigation of the upconversion mechanism and the intrinsic chemical complexity of co-doped TM, Ln systems. To this aim, we employ a pulsed, excitation variable laser across a complete set of UC measurements, such as the emission and excitation spectra and emission decays and analyze multiple grains with transmission electron microscopy (TEM). In the Mo co-doped garnet, the results sustain the co-existence of Mo-free garnet and Mo oxide impurity. In this Mo oxide, the Er upconversion emission properties are fully explained by a relatively efficient sequential Yb to Er upconversion process, with no contribution from Yb-Mo dimer sensitization.

Metamorphic Evolution of the Garnet Amphibolite Schist from Mawat Ophiolite, Kurdistan Region, Northeast Iraq: Geochemistry, Mineral Chemistry and Thermodynamic Approach

The garnet amphibolite schist is associated with the gabbroic unit of the Mawat ophiolite, Kurdistan region, Northeast Iraq, in the imbricated zone of the Zagros orogenic belt. Field observation, petrographic study, mineral chemistry, geochemical data, and thermodynamic modeling were used to demonstrate mineral identification, predict the observed stable mineral assemblages, and validate the protolith. The mineral assemblages of prograde are garnet (pyrope-almandine), chlorite (clinochlore), amphibole (grunerite), plagioclase (anorthite), iron oxides while the garnet (almandine-pyrope), chlorite (chamosite), amphibole (cummingtonite), and iron oxide represent retrograde assemblage. The relict pod of metagabbro in the center of the garnet amphibolite schist body consists mainly of plagioclase, amphibole, pyroxene, and iron oxide. Geochemical data reveals that the rock is depleted in SiO2 and CaO and enriched in refractory elements compared to the metagabbro. This may be attributed to the generation of silicic melts by partial melting and producing nearby plagiogranite. The rare earth elements (REE) patterns show that the garnet amphibolite schist is depleted in light rare earth elements (LREE) and gradually enriched in heavy rare earth elements (HREE). Thermodynamic modeling, field observation, combined with petrographic study constrains two metamorphic stages and one possible anticlockwise P-T-t path for garnet amphibolite schist, with increasing pressure and temperature of gabbroic rocks units of Mawat ophiolite. The rocks reached peak metamorphic conditions at more than 800 °C and 8–10 kbar, which partially melted the rock produced prograde resitite and melt. Later, the resitite rock retrograded to the lower stage at temperatures ranging from 620 to 650 °C and pressures ranging from 6.5 to 6.8 kbar. Anticlockwise P-T-t paths suggested based on geochemical and thermodynamic data for garnet amphibolite schist of the Mawat ophiolite. Moreover, the gabbro is considered to be the protolith of garnet amphibolite schist, which have been undergone eclogite facies metamorphism later overprinted by amphibolite facies.

Influence of Luminescent Properties of Powders on the Fabrication of Scintillation Ceramics by Stereolithography 3D Printing

Luminescent and scintillation ceramic materials with complex shapes, which can be created by stereolithography 3D printing, are of interest for special phosphor and detector applications. Starting powders for such ceramics may possess UV absorption bands; therefore, it is important to study the possible influence of the powders’ luminescent properties on the printing process. This paper deals with complex garnet oxides, Y3Al5O12 and Gd3Al2Ga3O12—well-known hosts for luminescent materials. The photopolymerization rates of slurries based on the luminescent powders produced by various chemical routes are studied, as well as available printing regimes. The slurries containing Ce-doped powders with a broad absorption band in UV have significantly lower photopolymerization rates compared to the undoped ones; a high Ce doping virtually hinders printing with layers thicker than 25–50 μm. Furthermore, the choice of powder synthesis method is shown to influence the printing process. Slurries with Tb-doped powder, with absorption lines at shorter wavelengths, have good photopolymerization activity, close to that of the undoped powder, and can be printed with layer thicknesses of 25–100 μm.

Investigation of metasomatism using Cu, Zn and Fe stable isotopes: Rodingitization of mafic and ultramafic rocks in ophiolites from northern Greece

Rodingites, a high-Ca content variety of metasomatic rocks, have been found in the Veria-Naousa and Edessa ophiolites, in northern Greece. The rodingites from both areas are characterized by a substantial overprint of primary textures. Coupled field and petrographic observations reveal derivation from ultramafic and mafic protoliths. The mineral phases in the ultramafic-derived rodingites (UDR) include mainly diopside, garnet, chlorite, tremolite, and FeTi oxides whereas mafic-derived rodingites (MDR) contain diopside, garnet, vesuvianite, chlorite and quartz. Here we present, for the first time, whole rock Cu, Zn and Fe isotopic data for the UDR and MDR from the Veria-Naousa and Edessa ophiolites, to investigate the evolution of this peculiar metasomatic lithotype. All the studied rodingites present δ65Cu values varying from −0.17 ± 0.03‰ to +0.62 ± 0.05‰ and δ66Zn ranging from −0.06 ± 0.03‰ to +0.74 ± 0.06‰. 0.0. Copper isotope ratios are systematically heavier in rodingites compared to their respective protoliths whereas Zn shows a diverse behavior with enrichment in its light isotopes (group 1: comprising all the UDR and a MDR sample) or in its heavy isotopes (group 2, the rest MDR samples). The same gabbroic protolith can lead to both group 1 and 2 rodingites with respect to their Zn isotopic ratios. Alkaline conditions of the hydrothermal metasomatic fluids and the inferred sulfide and bisulfide ligands promoted mobility of Cu and Zn and have likely played a major role to their isotopic behavior in the rodingites. In contrast, Fe isotopes have not fractionated during rodingitization. Complex metasomatic processes, such as rodingitization, have a clear impact on stable isotope fractionation, which is decoupled between the Cu, Zn and Fe isotope systems. The lack of correlation between isotope ratios and any mineralogical or elemental indicator highlights the absence of any profound relationship between isotope fractionation and mineral phases, which could reflect the stage and evolution of rodingitization. The consistent isotopic behavior of Cu indicates a promising geochemical tool to distinguish metasomatized and non-metasomatized samples within different observed groups, and define conditions and parameters during Ca-metasomatism, regardless the degree of rodingitization, prior alteration and various protoliths compositions. Additionally, Zn isotopes give a useful insight on the metasomatic conditions for both ultramafic and mafic precursors defining local pH changes coupled with available ligands, HS−, where Cu isotopes alone would not be able to describe.

Analysis and optimization of mass percentage of zycoprint polymer and abrasives in achieving stability of suspension mixture in abrasive water jet machining

The suspension parameters are vital in the suspension-type abrasive water jet (AWJ) machining of several engineering materials, more so in difficult-to-cut materials, because it significantly influences the suspension stability and sedimentation behaviour of the suspension mixture and abrasive particle acceleration into the AWJs. The suspension stability and abrasive particle acceleration of the suspension-type AWJs are improved by using polymer additives. Hence, it is necessary to study the effect of suspension parameters (abrasive and polymer concentrations) on suspension stability. In this direction, the novel work reported in the paper analyses the stability of suspension by varying the mass percentage of abrasives (garnet and aluminum oxide (Al 2 O 3 )) ( ω a ) and mass percentage of the zycoprint polymer ( ω p ) in water by considering the Taguchi L 9 Orthogonal array (OA). The linear regression (LR) models for the percentage of suspension volume with garnet ( V s G ) and the percentage of suspension volume with Al 2 O 3 ( V s A ), are developed. The JAYA algorithm is used to find the optimal combination of the suspension parameters, and its results are in close agreement with the findings from the LR results. The optimum setting of the suspension parameters for both, V s G and V s A , is 3% of ω a and 0.80% of ω p .

High-performance Ta-doped Li7La3Zr2O12 garnet oxides with AlN additive

Garnet-type oxide is one of the most promising solid-state electrolytes (SSEs) for solid-state lithium-metal batteries (SSLMBs). However, the Li dendrite formation in garnet oxides obstructs the further development of the SSLMBs seriously. Here, we report a high-performance garnet oxide by using AlN as a sintering additive and Li as an anode interface layer. AlN with high thermal conductivity can promote the sintering activity of the garnet oxides, resulting in larger particle size and higher relative density. Moreover, Li3N with high ionic conductivity formed at grain boundaries and interface can also improve Li-ion transport kinetics. As a result, the garnet oxide electrolytes with AlN show enhanced thermal conductivity, improved ionic conductivity, reduced electronic conductivity, and increased critical current density (CCD), compared with the counterpart using Al2O3 sintering aid. In addition, Li symmetric cells and Li∣LiFePO4 (Li∣LFP) half cells using the garnet electrolyte with the AlN additive exhibit good electrochemical performances. This work provides a simple and effective strategy for high-performance SSEs.

Achieving enhanced densification and superior ionic conductivity of garnet electrolytes via a co-doping strategy coupled with pressureless sintering

Lithium garnet oxides with 6.5 mol Li, such as Li6.5La3Zr1.5(Ta/Nb)0.5O12, typically crystallise in cubic structure and exhibit excellent room-temperature ionic conductivity close to 1 mS cm−1. However, it is challenging to densify garnet oxides. In this work, we investigated how the co-doping of tantalum (Ta) and niobium (Nb) affects the densification of pressureless sintered garnet electrolytes with compositions of Li6.5La3Zr1.5Ta(0.5−x)NbxO12, where x = 0–0.5. The highest densification (94.5% of relative density) was achieved in Li6.5La3Zr1.5Ta0.1Nb0.4O12 (TN-LLZO) when it was sintered at 1150 °C for 6 h. This TN-LLZO garnet electrolyte delivers an ionic conductivity of 1.04 × 10−3 S cm−1 (at 22 °C) with a low activation energy of 0.41 eV. Our findings demonstrate that the content of dopants (Ta and Nb) plays a critical role in enhancing the sintering performance of garnet ceramics at ambient pressure.

Ionic conductivity and ion transport mechanisms of solid‐state lithium‐ion battery electrolytes: A review

AbstractThis review article deals with the ionic conductivity of solid‐state electrolytes for lithium batteries. It has discussed the mechanisms of ion conduction in ceramics, polymers, and ceramic‐polymer composite electrolytes. In ceramic electrolytes, ion transport is accomplished with mobile point defects in a crystal. Li+ ions migrate mainly via the vacancy mechanism, interstitial mechanism, or interstitial‐substitutional exchange mechanism. In solid polymer electrolytes, Li+ ions are transported mainly via the segment motion, ion hopping (Grotthuss mechanism), or vehicle mechanism (mass diffusion). This study has also introduced various electrolyte materials including perovskite oxides, garnet oxides, sodium superionic conductors, phosphates, sulfides, halides, cross‐linked polymers, block‐copolymers, metal‐organic frameworks, covalent organic frameworks, as well as ceramic‐polymer composites. In addition, it has highlighted some strategies to improve the ionic conductivity of solid‐state electrolytes, such as doping, defect engineering, microstructure tuning, and interface modification.

Transport in Lithium Garnet Oxides as Revealed by Atomistic Simulations

Lithium garnet oxides are a family of fast-ion conductors with appreciable lithium ionic conductivity in the solid state, making them promising candidates as electrolytes for all-solid-state batteries. In their structures, lithium is partially (along with vacancy) distributed among more than one crystallographically distinct sites, just as with other fast-ion conductors. This disorder has a great influence on lithium's transport properties such as diffusivity and ionic conductivity. We review atomistic simulation studies in conjunction with complementary experimental investigations, which offer atomic-scale visualization of and insight into lithium transport phenomena in lithium garnet oxides.

Transparent Phosphor Thin Films Based on Rare‐Earth‐Doped Garnets: Building Blocks for Versatile Persistent Luminescence Materials

Afterglow properties of persistent phosphors are attracting a great deal of attention in the fields of bioimaging, sensing, labeling, safety, or security. Complex garnet oxides, especially those doped with Ce3+ and Cr3+, are particularly relevant to this end since their persistent luminescence can be tuned through matrix composition and activated by visible light, in contrast to the vast majority of persistent phosphors that require UV excitation. Most extended preparation routes yield micrometer‐sized phosphors that display strong light scattering, which limits their versatility and applicability. Herein, nanostructured garnet oxide‐based thin films that are transparent and feature persistent luminescence properties are demonstrated. Following a sol–gel route and after high temperature annealing, few hundred nanometre‐thick Y3Al2Ga3O12:Ce3+,Cr3+ transparent films showing efficient green emission and afterglow are attained. Gd3Al2Ga3O12:Ce3+,Cr3+ transparent thin films displaying yellow afterglow with distinct persistent kinetics are demonstrated, to prove the generality of the approach herein proposed. Its versatility is further demonstrated by developing layered phosphors with time‐dependent chromaticity due to the unique persistent emission color – upon blue light excitation – and kinetics of each layer forming the stack. The results pave an avenue toward nanodevices and multifunctional coatings in which afterglow offers hitherto unexplored properties.

Sedimentology, geomorphology, structural controls, and detrital zircon ages of the Itiquira River diamond placer deposits, Mato Grosso, western Brazil

The Itiquira River, Mato Grosso state (western Brazil), hosts several diamond placer deposits, mined intermittently over the last century. It runs over volcanic and sedimentary rocks of the Paraná Basin until it discharges in the northern Pantanal Basin. The bedrocks were deposited in marine, continental desertic, alluvial deltaic, and fluvial environments. The meanders of the Itiquira River are controlled by NE-SW, ENE-WSW, NNW-SSE, N–S, and NW-SE fractures and normal faults, developed in response to the evolution of the Paraná Basin and by neotectonics, linked with the development of the Pantanal Basin since the Paleogene. The Itiquira River middle valley, in which the diamondiferous placers are found, is controlled by NE-SW structures inherited from the Neoproterozoic Transbrasiliano Lineament. The landscape comprises dissected plateaus and structure-controlled valleys formed by Cretaceous, Paleogene, and Neogene planation processes. The diamonds occur in the muddy-sandy matrix of the current stream bed and older terraces gravels. In the Itiquira River, the diamond deposits are related to the following traps: point bars, cut-and-fill channels, pockets, and potholes. Sapphire, garnet (including kimberlitic), ilmenite, zircon, rutile, gold, and iron oxides are documented as heavy minerals in the gravels. Detrital zircon dating of grains extracted from the Itiquira River diamond deposits resulted in the ages of 2057, 1184, 873, 645–508, 307–207, and 144-142 Ma. The potential zircon sources are the Goiás Magmatic Arc granitoids, Paraguay Belt metavolcanics and granites, and Serra Geral Formation volcanics. The ages between 307 and 207 Ma are likely to be from an unknown (possibly kimberlitic) source. The Itiquira River tectonic, geomorphological, and sedimentological evolutions suggest potential sources for the diamond placers and paleoplacers.

Study of diffusion and conduction in lithium garnet oxides LixLa3Zrx-5Ta7-xO12 by machine learning interatomic potentials.

Lithium garnet oxides are an attractive family of solid-state electrolytes due to their high Li-ion conductivity and good chemical stability against Li metal. Experimental study of these materials is often troubled by chemical contamination (e.g. Al) or lithium loss, while computational study, theoretically with controlled composition, is often limited either by accuracy (e.g. conventional interatomic potential) or efficiency (e.g. density-function theory or DFT). In this work, we report the study of diffusion and conduction of lithium garnets by a machine learning interatomic potential (MLIP) that is approaching DFT accuracy but orders of magnitude faster. We found that this MLIP is more accurate than other commonly applied models to study lithium garnets and is able to predict diffusion and conduction properties that are consistent with experiments. Computational studies enabled by this MLIP, combined with experimental data, suggest that ionic conduction is non-Arrhenius and maximum conductivity occurs around x = 6.6 to 6.8 in LixLa3Zrx-5Ta7-xO12.

Optimization for polyethylene glycol/garnet oxide composite electrolyte membrane for solid-state batteries

To achieve solid-state batteries with high conductivity, polymer electrolyte membranes blended with inorganic fillers are attracting greater interests. Current work is mainly focused on Li+ migration mechanism for optimized composite electrolyte membrane (CEM). Herein, 6.71 vol% (37.50 wt%) Al-doping Li7La3Zr2O12 dispersed in polyethylene glycol (PEG)-LiClO4 matrix shows the maximal ionic conductivity (∼1.56 × 10−4 S cm−1 at 45 °C) and high cycling reversibility (≥380 cycles). Garnet oxide fillers enlarge the amorphous region and electrochemical stability, and the higher amorphous level of PEG matrix enables a high Li+ dissolution and a rapid Li+ migration. Time-of-flight secondary ion mass spectrometry is employed to locate Li+ migration pathways, and the results indicate that Li+ migration depends on the amorphous phase in the CEM. Therefore, an empirical equation has been proposed to simulate the relationship of mass ratio and volume ratio of fillers. With a close connection between the CEM and two electrodes, a solid-state lithium-metal battery assembled with the NCM111 cathode delivers an average capacity of ∼108 mAh g−1 at C/25 and after 200 cycles.

Rational design of CO2 electroreduction cathode via in situ electrochemical phase transition

CO2 electroreduction reaction (CO2RR), combined with solid oxide electrolysis cells (SOECs), is a feasible technology for the storage of renewable electric energy, while its development is limited by the catalytic activity and stability on cathodes. Here, a novel garnet oxide (Gd3Fe5O12) cathode is designed, where the garnet oxide is converted to perovskite oxide and iron via in situ electrochemical phase transition during CO2 electroreduction, resulting in high activity with Faradaic efficiency close to 100% and great stability over 1000 h galvanostatic test. A variety of experimental characterizations and density functional theory calculations indicate that in situ exsolved Fe clusters can effectively enhance the adsorption energies of intermediates and lowering the CO2 dissociation barriers. Microkinetic modelling confirms that CO2RR goes through a dissociative adsorption mechanism and the electronic transfer for CO2 dissociation is the rate-determining step.