Development Of Solid-state Batteries Research Articles

Solid-state Batteries: Overcoming Challenges and Harnessing Opportunities for a Sustainable Energy Future

Herein we reviewed solid-state batteries (SSBs) as an emerging and promising alternative to conventional lithium-ion batteries, offering enhanced energy density, safety, and longevity. Solid-state batteries (SSBs) use a solid electrolyte instead of the liquid or gel electrolytes found in conventional lithium-ion batteries. SSBs can achieve energy densities of up to 500 Wh/kg, compared to 350 Wh/kg for conventional lithium-ion batteries. This paper explores the potential of SSBs to revolutionize grid stability and energy storage. The unique characteristics of SSBs, including their solid-state electrolytes (SSEs) and absence of liquid components, significantly mitigate safety concerns associated with traditional batteries. Moreover, SSBs exhibit higher faster charging rates, making them ideal for applications demanding high energy storage capacity and rapid response times. The paper further discusses the key challenges and advancements in SSB development, including material selection, manufacturing processes, and cost reduction. It also highlights the anode and cathode materials but also the interface challenges faced during the design and development of SSBs. By addressing the limitations of current energy storage solutions, SSBs offer a promising pathway toward a more resilient and sustainable energy future.

Fabrication of 60μm-Thick Free-Standing Bilayer Solid Electrolytes for Solid-State Batteries Using Solution Processing and Lamination

Development of solid-state batteries with a high voltage cathode and lithium metal anode could enable high energy density while avoiding safety issues of flammable liquid electrolytes. However, the solid electrolyte (SE) should meet multiple requirements, including 1) electrochemical stability at both the cathode and anode side interfaces, 2) small thickness (tens of μm) to maximize energy density of the cell, and 3) fabrication with a scalable manufacturing method. Using bilayer SEs with different electrochemical stability windows could enable stability at both cathode|SE and anode|SE interfaces. In this work, we developed a manufacturing process to fabricate thin (60 μm) free-standing bilayer SE films from slurry casting and lamination, which can be used for large scale manufacturing of SSBs.Halide SE (Li3InCl6) and sulfide SE (Li6PS5Cl) were slurry casted on different substrates, and then were dried in vacuum before being laminated onto each other to make a free-standing bilayer film. The parallel slurry casting approach eliminates cross-compatibility requirements of the solvents used for slurry preparation. The resulting bilayer films after densification were pin-hole free without intermixing between the two phases. The ionic conductivity of the bilayer SE film was ~70% of the bilayer SE pellet (1 mm thickness in total) made with a conventional powder pressing method. However, because the thickness of bilayer SE film (60 μm) was much smaller than the bilayer SE pellet (1 mm), the bilayer SE film had ~10x lower area-specific resistance (ASR) compared to the bilayer SE pellet. Because of the lower total cell resistance, the cell made with the bilayer SE film had a better rate capability compared to the reference cell in pellet geometry.The strategy developed in this work could be integrated into current manufacturing infrastructure of battery fabrication as it is based on slurry casting, which is already a well-established fabrication method for lithium-ion batteries. Moreover, it could be used to fabricate multi-layered solid-state architectures in general, which are challenging to manufacture due to solvent compatibility issues during slurry casting. The study will assist the progress of solid-state battery manufacturing by providing a scalable manufacture method to prepare thin free-standing bilayer SEs.

Mechanically and Thermally Robust Gel Electrolytes Built from A Charged Double Helical Polymer.

Polymer electrolytes have received tremendous interest in the development of solid-state batteries, but often fall short in one or more key properties required for practical applications. Herein, a rigid gel polymer electrolyte prepared by immobilizing a liquid mixture of a lithium salt and poly(ethylene glycol) dimethyl ether with only 8 wt% poly(2,2'-disulfonyl-4,4'-benzidine terephthalamide) (PBDT) is reported. The high charge density and rigid double helical structure of PBDT lead to formation of a nanofibrillar structure that endows this electrolyte with stronger mechanical properties, wider temperature window, and higher battery rate capability compared to all other poly(ethylene oxide) (PEO)-based electrolytes. The ion transport mechanism in this rigid polymer electrolyte is systematically studied using multiple complementary techniques. Li/LiFePO4 cells show excellent capacity retention over long-term cycling, with thermal cycling reversibility between ambient temperature and elevated temperatures, demonstrating compelling potential for solid-state batteries targeting fast charging at high temperatures and slower discharging at ambient temperature.

Unraveling the evolution of Cathode–Solid electrolyte interface using operando X-ray Photoelectron spectroscopy

Understanding the evolution of the solid electrolyte-electrode interface is currently one of the most challenging obstacles in the development of solid-state batteries (SSBs). Here, we develop an X-ray Photoelectron Spectroscopy (XPS) that allows for operando measurement during cycling. Based on theoretical analysis and the modulated electrode and detector co-grounding mode, the displacement of binding energy can be correlated with the surface electrostatic potential of the material, revealing the charge distribution and composition evolution of the space charge layer between the cathode and the electrolyte. In the investigation of typical LiCoO2 (LCO)/Li6PS5Cl (LPSC)/Li–In batteries, we observed the static potential difference and oxidative decomposition between LPSC and LCO, and the effectiveness of the LiNbO3 coating in reducing potential difference and inhibiting the diffusion of Co and oxidation of S species. Furthermore, our study also revealed that the potential drop between LiNi0·8Co0·1Mn0·1O2 and LPSC is smaller than that of LCO, whilst that between Li3InCl6 and LCO remains near zero. The proposed operando XPS method offers a novel approach for real-time monitoring of interface potential and species formation, providing rational guidance for the interface engineering in SSBs.

Investigation of Aliovalent Substitution in the Solid Sodium Ion Electrolyte Na2ZrCl6

The research community is working hard on the development of solid-state batteries (SSB) as an alternative to commercialized lithium-ion batteries, due to their higher energy density and enhanced safety. One of the core research areas of SSBs is the solid-state electrolyte (SE), which should fit the demand for high ionic conductivity and electrochemical stability at the same time. Recently, halide SEs have emerged because they are mechanochemical processable, similar to sulfidic SEs, but halide SEs exhibit excellent electrochemical oxidation stability compared to sulfidic SEs [1,2].However, the relatively low ionic conductivity at room temperature still hinders the application of halide SE in SSBs. Aliovalent substitution is a very widely used method to improve the ionic conductivity of SEs [3,4]. We are also motivated by the application of earth-abundance elements to reduce raw material costs.Recently, significant focus has been gained by Zr-based compounds such as Na2ZrCl6. We investigate here such compounds, focusing on elemental substitutions to gain increased ionic conductivity and on gaining insight into the influence of synthesis on SE crystal structure and electrochemical properties.In our work, different amounts of elemental substitutions are investigated, and the related materials are synthesized at different temperatures. In particular, the influence of a series of subsequent heating temperatures on the structure of the binary system is studied through XRD diffraction analysis and further refinement. The Ionic diffusion paths are also estimated through the band valence sum approach, in order to validate the electrochemical impedance spectroscopy (EIS) results.In summary, we report our early results on the development of novel solid electrolytes for Na-based solid-state batteries.REFERENCES[1] Kwak, H.; Lyoo, J.; Park, J.; Han, Y.; Asakura, R.; Remhof, A.; Battaglia, C.; Kim, H.; Hong, S.-T.; Jung, Y. S. Na2ZrCl6 enabling highly stable 3 V all-solid-state Na-ion batteries. Energy Storage Mater. 2021, 37, 47−54.[2] Tong Zhao, Alexander N. Sobolev, Roman Schlem, Bianca Helm, Marvin A. Kraft and Wolfgang G. Zeier. Synthesis-Controlled Cation Solubility in Solid Sodium Ion Conductors Na2+xZr1 - xInxCl6. ACS Appl. Energy Mater. 2023, XXXX, XXX, XXX-XXX.[3] Schlem, R.; Banik, A.; Eckardt, M.; Zobel, M.; Zeier, W. G. Na3-xEr1-xZrxCl6-A Halide-Based Fast Sodium-Ion Conductor with Vacancy-Driven Ionic Transport. ACS Appl. Energy Mater. 2020, 3, 10164−10173.[4] Wu, E. A.; Banerjee, S.; Tang, H.; Richardson, P. M.; Doux, J.M.; Qi, J.; Zhu, Z.; Grenier, A.;Li, Y.; Zhao, E.; Deysher, G.; Sebti, E.;Nguyen, H.; Stephens, R.; Verbist, G.; Chapman, K. W.; Clement, R.J.; Banerjee, A.; Meng, Y. S.; Ong, S. P. A stable cathode-solid electrolyte composite for high-voltage, long-cycle-life solid-state sodium-ion batteries. Nat. Commun. 2021, 12, 1256.

Sulfide-Based Solid-State Lithium-Sulfur Batteries: An in-Depth Study of the Li-Electrolyte Interface

The development of solid-state batteries has gained significant attention in recent years, owing to their potential to enhance the temperature range and energy density of energy storage devices. Sulfide-based electrolytes are some of the most promising candidates for solid-state batteries, thanks to their high ionic conductivity and low processing temperature. For lithium-sulfur (Li-S) batteries, the transition from liquid to solid electrolytes holds even greater promise. Sulfur is a readily available cathode material known for its high specific capacity, which endows Li-S batteries with remarkable specific energy and favourable environmental and economic impact. In liquid electrolytes however, the solubility of sulfur and lithium polysulfide causes a multitude of issues that hamper the performance of the Li-S system: rapid self-discharge, redox shuttle mechanism during charging, and loss of active sulfur and lithium material due to direct chemical reactivity. Solid-state Li-S cells are not prone to these issues, but they have, of course, issues of their own. Amongst them, the stability of the interface between the electrolyte and the lithium is of crucial importance to allow the use of this very high energy density negative electrode.In the present study, we compare two sulfide electrolytes, Li6PS5Cl and Li7P3S11, and assess their respective stability against lithium. We used innovative methods to characterize the interphase between the sulfide and the lithium without damaging it upon dismantling the cell. The nature and the properties of this interphase was characterised via EIS, XPS and ToF-SIMS.The EIS study showed that Li6PS5Cl forms a much more stable interphase with lithium than Li7P3S11, which is in accordance with most recent results in the literature. The XPS study confirmed the chemical composition of the interphase. Li2S and Li3P were present for both electrolytes. In the case of Li6PS5Cl, LiCl was also identified as expected. Gas cluster ion beam (GCIB) assisted abrasion of the interphase followed by in-situ XPS and ToF-SIMS suggested a separation of the components of the interphase depending on the depth of the abrasion. The interphase was found to be organised as Li2S-, Li3P- or LiCl-rich discrete layers, with the Li2S-rich layer being consistently the closest to lithium. This result confirms and completes the most recent research in the field published by Otto et al. in 2022 (doi: 10.1002/admi.202102387).To establish solid-state batteries as a practical energy storage option, it is essential to fully understand and effectively manage the Li-electrolyte interface. These findings suggest that thanks to the relative stability of its interface with lithium, Li6PS5Cl is the better option for solid-state lithium metal cells. It also sheds light on the reasons why this interface is more stable. The self-assembled lamellar structure of the interphase could also inspire strategies to better control the stability of solid electrolytes versus lithium.

Design and Optimization of Composite Cathodes for Solid-State Batteries Using Hybrid Carbon Networks with Facile Electronic and Ionic Percolation Pathways.

Solid-state batteries (SSBs) have emerged as a promising alternative to conventional liquid electrolyte batteries due to their potential for higher energy density and improved safety. However, achieving high performance in SSBs is difficult because of inadequate contact and interfacial reactions that generate high interfacial resistance, as well as inadequate solid-solid contact between electrodes. These chronic issues are associated with inhomogeneous ion and electron transport networks owing to imperfect solid-solid interfacial contact. This study developed an optimal interfacial engineering strategy to facilitate an ion-electron transport network by designing an active material (NCM622) uniformly filled with a thin layer of a solid electrolyte (garnet-type Li6.25Ga0.25La3Zr2O12) and conductive additives. The optimal composite electrode architecture enhanced the high capacity, high rate capability, and long-term cycle stability, even at room temperature, owing to the percolating network for facile ionic conduction that assured a homogeneous reaction. In addition to mitigating the mechanical degradation of the cathode electrode, it also reduced the crosstalk effects on the anode-solid electrolyte interface. Effectively optimizing the selection and use of conductive additives in composite electrodes offers a promising approach to addressing key performance-limiting factors in SSBs, including interfacial resistance and solid-solid contact issues. This study underscores the critical importance of cathode architecture design for achieving high-performance SSBs by ensuring that the interfaces are intact with solid electrolytes at both the cathode and anode interfaces while promoting uniform reactions. This study provides valuable insights into the development of SSBs with improved performance, which could have significant implications for a wide range of applications.

Development of composite solid polymer electrolyte for solid-state lithium battery: Incorporating LLZTO in PVDF-HFP/LiTFSI

Solid-state batteries (SSBs) are regarded as favorable future technology as they promise to deliver high energy density and improved safety. However, despite extensive research efforts, the development of SSBs still fall short of expectations mainly because of suitable solid electrolyte which can provide high ionic conductivity as well as good flexibility to enhance interface contact between electrolyte and electrodes. In this work, we have prepared free-standing, flexible composite solid polymer electrolyte (CSPE) membranes by incorporating LLZTO ceramic particles in PVDF-HFP/LiTFSI based solid polymer electrolyte (SPE). Addition of 20 wt% LLZTO has shown to improve the electrochemical properties of the solid electrolyte such as ionic conductivity (8.2 × 10−4 S cm−1 at 60 °C), transference number, electrochemical stability and long-term interface stability with the lithium-metal also showed significant improvement. Furthermore, solid-state LiFePO4/SPE/Li and LiFePO4/CSPE/Li batteries were fabricated, and charge/discharge cycling was performed, where battery with SPE and CSPE exhibited discharge capacity of 119 mA h g−1 and 131 mA h g−1 respectively at 0.1C rate, 60 °C.

Non-Linear Kinetics of The Lithium Metal Anode on Li6 PS5 Cl at High Current Density: Dendrite Growth and the Role of Lithium Microstructure on Creep.

Interfacial instability, viz., pore formation in the lithium metal anode (LMA) during discharge leading to high impedance, current focusing induced solid-electrolyte (SE) fracture during charging, and formation/behaviour of the solid-electrolyte interphase (SEI), at the anode, is one of the major hurdles in the development of solid-state batteries (SSBs). Also, understanding cell polarization behaviour at high current density is critical to achieving the goal of fast-charging battery and electric vehicle. Herein, via in situ electrochemical scanning electron microscopy (SEM) measurements, performed with freshly deposited lithium microelectrodes on transgranularly fractured fresh Li6PS5Cl (LPSCl), the LiǀLPSCl interface kinetics are investigated beyond the linear regime. Even at relatively small overvoltages of a few mV, the LiǀLPSCl interface shows non-linear kinetics. The interface kinetics possibly involve multiple rate-limiting processes, i.e., ion transport across the SEI and SE|SEI interfaces, as well as charge transfer across the LiǀSEI interface. The total polarization resistance RP of the microelectrode interface is determined to be ≈ 0.8 Ω cm2 . It is further shown that the nanocrystalline lithium microstructure can lead to a stable LiǀSE interface via Coble creep along with uniform stripping. Also, spatially resolved lithium deposition, i.e., at grain surface flaws, grain boundaries, and flaw-free surfaces, indicates exceptionally high mechanical endurance of flaw-free surfaces toward cathodic load (>150mA cm-2 ). This highlights the prominent role of surface defects in dendrite growth.

The Effect of Pressure during Sintering on the Interface between Oxide Solid Electrolyte and Cathode in Solid State Lithium Batteries

Conventional Li-ion batteries (LIBs), which have been widely used as main power sources for various electronic devices, are facing huge challenges with the explosive growth of electric vehicles (EVs) market. The safety problems of LIBs in EVs causing fire incident mainly result from the use of liquid electrolytes which provide fuel for combustion. Therefore, solid state lithium batteries using a solid electrolyte are widely accepted as promising candidates for next generation energy storage devices with superior safety performances. However, solid state batteries have limitations that originate from solid-solid interfaces between electrode and solid electrolyte, hindering practical development of solid state batteries. Especially, compared to sulfide based solid electrolyte, oxide based solid electrolyte is rigid, resulting in difficulty in forming intimate contact between solid electrolyte and electrode materials. In this study, using lithium vanadium phosphate (Li3V2(PO4)3, LVP) and lithium aluminum germanium phosphate (Li1.5Al0.5Ge1.5(PO4)3, LAGP) as cathode material and oxide solid electrolyte model system, we demonstrate the effect of pressure during sintering on the contact between LVP and LAGP, and concomitant cell performance. In addition, we found that the crystallinity of solid electrolyte and the content of carbon conducting agent critically affect the contact. Without any complicated interfacial modification, we successfully made decent cathode-solid electrolyte interface with simple method for superior solid state lithium batteries.

(Invited) Mechanistic Interrogation of Solid/Solid Interfaces

Solid-state batteries (SSBs) that pair a lithium metal anode with an inorganic solid electrolyte hold promise to simultaneously improve the energy density, power density and safety as compared to conventional lithium-ion batteries. However, the development of SSBs is confronted with challenges including electrochemical-transport-mechanics interplay and morphological instability at various solid-solid interfaces. Toward achieving practical SSBs, gaining a fundamental understanding of the mechanistic interactions and systematically correlating those to interface stability and performance is critical. In this presentation, we delineate the distinct asymmetry in the electrochemical-mechanical interaction, limiting mechanisms and interface response during operation. The mechanistic role of heterogeneities that underlie at solid-solid interfaces on the stress-transport-kinetics interplay will be discussed.

Preparation of Li-Si-P-S-O-N Glasses: The Impact of Lipon Incorporation on Ionic Conductivity

Lithium glassy solid electrolytes (GSEs) are an alternative to liquid electrolytes in the development of solid-state batteries. Mixed oxy-sulfide nitride GSEs incorporate the useful properties of sulfide glasses, which show high ionic conductivity, of oxide glasses which display excellent chemical stability, and of nitride glasses which exhibit good electrochemical stability. In our investigation of these new GSEs, the following compositional series was explored Li2S + SiS2 + [(1-x)Li0.67PO2.83 + xLiPON]. Differential scanning calorimetry (DSC) was employed to determine the crystallization and glass temperatures of these GSEs. In addition, electrochemical impedance spectroscopy (EIS) was used to determine the temperature-dependent ionic conductivity of theses GSEs. X-ray Photoelectron Spectroscopy (XPS) was conducted on the glasses to further understand the chemical bonding environment of nitrogen. It was found that x = 0.2 displayed the highest ionic conductivity suggesting that nitrogen incorporation can be used to optimize mixed oxy-sulfide glasses.Support of this research by NSF Grant NSF-DMR-1936913 is acknowledged.

Recent Advances in Stability Issues of Inorganic Solid Electrolytes and Composite Solid Electrolytes for All-Solid-State Batteries.

The development of solid-state batteries has become one of the most promising directions in rechargeable secondary batteries due to their considerable energy densities and favorable safety. However, solid-state batteries with higher energy density and more durable and stable cycle life should be developed for large-scale energy storage and adaption to the rapidly increasing lithium battery production and sales market. Although inorganic solid electrolytes (ISEs) and composite solid electrolytes (CSEs) are relatively advantageous solid-state electrolytes, they also face severe challenges. This review summarizes the main stability issues related to chemical, mechanical, thermal, and electrochemical aspects faced by ISEs and CSEs. The corresponding state-of-the-art improvement strategies have been proposed, including filling of modified particles, electrolyte pore adjustment, electrolyte internal structure arrangement, and interface modification.

Enhancing the Performance of Ceramic-Rich Polymer Composite Electrolytes Using Polymer Grafted LLZO

Solid-state batteries are the holy grail for the next generation of automotive batteries. The development of solid-state batteries requires efficient electrolytes to improve the performance of the cells in terms of ionic conductivity, electrochemical stability, interfacial compatibility, and so on. These requirements call for the combined properties of ceramic and polymer electrolytes, making ceramic-rich polymer electrolytes a promising solution to be developed. Aligned with this aim, we have shown a surface modification of Ga substituted Li7La3Zr2O12 (LLZO), to be an essential strategy for the preparation of ceramic-rich electrolytes. Ceramic-rich polymer membranes with surface-modified LLZO show marked improvements in the performance, in terms of electrolyte physical and electrochemical properties, as well as coulombic efficiency, interfacial compatibility, and cyclability of solid-state cells.

Exploring the Synthesis of Alkali Metal Anti-perovskites

The development of solid-state batteries has been slowed by limited understanding of the features that control ion mobility in solid electrolytes (SEs). In the case of anti-perovskite (AP) SE, lattice distortions have been proposed as one such controlling factor: APs that exhibit distortions of the octahedral building blocks are predicted to exhibit enhanced ionic mobility. Nevertheless, large distortions come at the cost of stability, implying a tradeoff between stability and ionic mobility. The present study combines theory and experiments to explore the synthesizability of several marginally stable APs predicted to exhibit high mobility for Li+, Na+, and K+. Density functional theory calculations, in combination with the quasi-harmonic approximation, were used to predict the free energy change, ΔGr(T), for synthesis reactions involving 36 alkali metal-based APs, X3AZ (X = Li, Na, or K; A = O, S, or Se; and Z = F, Cl, Br, or I). A linear correlation is observed between the degree of lattice distortion and the stabilization temperature, at which ΔGr(T) = 0. Hence, APs with the highest ionic mobility generally require the highest synthesis temperature. These data were used to guide experimental synthesis efforts of APs by estimating the temperatures above which a given AP is expected to be thermodynamically stable. Attempts were made to synthesize several AP compositions; overall, good agreement is obtained between experiments and computation. These data suggest that a compound’s zero K decomposition energy is an efficient descriptor for predicting the ease and likelihood of synthesizing new SEs.

Microstructure and ionic conductivity of Li0.5-xLa0.5(Ti1-xNbx)O3 solid-state electrolytes

Solid electrolytes are critical in the development of solid-state batteries, which have advantages in terms of safety and stability. Lithium Lanthanum Titanate (Li3xLa2/3-xTiO3) is regarded as one of the most favored candidate solid electrolytes. However, the doping dependences of ionic conductivity and microstructure are still poorly understood. In this work, nominal Li0.5-xLa0.5(Ti1-xNbx)O3 (LLTN, x = 0, 0.01, 0.03, 0.05 and 0.07, labelled as LLTN0, LLTN1, LLTN3, LLTN5, LLTN7, respectively) ceramics are synthesized to investigate the above doping effects. The bulk ionic conductivity of LLTN5 sample reaches as high as 0.71 × 10−3 S/cm, which is approximately two times higher than the bulk ionic conductivity of the undoped sample at room temperature. The XRD refinement and Raman results indicate that niobium doping increases the lattice cell along the c-axis and stretch the TiO bond, which extends the tunnels for Li-ions diffusion. This work suggests that it is effective to enlarge the lattice cell for the improvement of the Li-ion conductivity in LLTO.

Harnessing artificial intelligence to holistic design and identification for solid electrolytes

Despite extensive studies, the development of solid-state batteries (SSBs) has not yet met expectations, owing mainly to the lack of suitable solid electrolytes (SEs) that exhibit low electronic conductivity (σe), high ionic conductivity (σi), and good stability. Here, we propose an effective target-driven framework for holistic identifying promising garnet-type SEs. Using artificial intelligence (AI) technologies, we accurately predict the σe with a mean absolute error of 0.25 eV, achieving a computed speed that is ~109 faster than ab initio calculations. Successfully, from 29,008 garnets, we discovered 12 promising super Li-ion conductors for SEs with σe < 3.6 × 10−30 S cm−1, σi > 10−4 S cm−1 (up to 3.24 S cm−1), and good thermal stability at room temperature and high temperature based on rigorous ab initio validation. These emerging SEs are expected to be used in Li-ion SSBs, thus improving the safety, performance, and lifetime of state-of-the-art energy storage technology. This approach directly cuts across at least 95 years of computational cycles to screen SEs, resulting in significant cost savings and helping us enter an electrified future that relies less on fossil fuels. The data that support the machine learning model of this study are available at: https://www.materialsproject.org.

An All-Solid-State Battery with a Tailored Electrode–Electrolyte Interface Using Surface Chemistry and Interlayer-Based Approaches

Major challenges in the development of solid-state batteries using garnet-type solid-state electrolytes (SSEs) include suppressing dendrite growth, improving moisture stability, and reducing interf...

Electrochemical Analysis of Garnet-Type Solid Electrolytes – Effect of Dopants on Li-Conductivity and Dendrites Formation

The development of solid state lithium-metal batteries (SSLB) is a key requirement to enable the use of energy storage systems with high energy and power densities in the automotive sector. Garnet-type solid electrolytes are considered suitable electrolytes candidates for SSLB due to their stability against lithium metal and high ionic conductivity at room temperature (10-3 S cm-1). Currently their use is limited because of their short life-time due to high interfacial resistance between electrode and electrolyte, and to the formation of lithium dendrites.1 A better understanding of the transport properties and the mechanism of dendrites formation in garnet type electrolytes is therefore required in order to develop solid electrolytes with a long enough life-time to be employed in commercial systems. In this work, alongside to an extended and systematic electrochemical characterisation of garnet-type electrolytes by Electrochemical Impedance Spectroscopy (EIS),2 we employed cubic Al- and Ga- doped Li7La3Zr2O12 (LLZO) as solid electrolytes in symmetrical cells and we investigated the formation of dendrites as a result of electrochemical cycling. We suggest that the presence of local chemical inhomogeneities promoted by the type of dopants used to stabilise the cubic phase might greatly affect the critical current density (CCD) for the dendrites formation and propagation.3 This is of fundamental importance for the development of solid state batteries based on LLZO. 1 A. Sharafi et al., J. Power Sources, 2016, 302, 135–139 2 F. M. Pesci et al., Manuscript in preparation 3 F. M. Pesci et al. , J Mater. Chem. A, 2018 , 6, 19817-19827

LAGP|Li Interface Modification through a Wetted Polypropylene Interlayer for Solid State Li-Ion and Li–S batteries

The development of solid state batteries is constrained by imperative factors like the high reactivity of lithium with solid electrolytes, high grain boundary resistance of the solid electrolyte, a...