High Interfacial Impedance Research Articles

Ce doped UiO-66(Hf) electrolyte for all-solid-state lithium metal batteries

Solid electrolytes have garnered significant attention as promising candidates for all-solid-state batteries due to their excellent safety, and cycling stability. However, the development of solid electrolytes faces challenges in achieving high ionic conductivity and low interfacial impedance. In this study, we prepared a Ce doped UiO-66(Hf)-base electrolyte using a solvothermal method. The resulting electrolyte exhibited remarkable properties, including high Li-ion conductivity (3.72 × 10−3 S cm−1), a high lithium ion transfer number (tLi+ = 0.66), and stability during stripping electroplating. These impressive results can be attributed to that the shorter length of the Ce-O bond in UiO-66(Hf) compared to the Hf-O bond, which enhances the transformation of Li+ ions. The incorporation of Ce as a dopant into UiO-66(Hf) in solid electrolytes holds great promise for future applications in solid-state batteries.

Synthesis and Properties of Polyvinylidene Fluoride-Hexafluoropropylene Copolymer/Li6PS5Cl Gel Composite Electrolyte for Lithium Solid-State Batteries.

Gel electrolytes for lithium-ion batteries continue to replace the organic liquid electrolytes in conventional batteries due to their advantages of being less prone to leakage and non-explosive and possessing a high modulus of elasticity. However, the development of gel electrolytes has been hindered by their generally low ionic conductivity at room temperature and high interfacial impedance with electrodes. In this paper, a poly (vinylidene fluoride)-hexafluoropropylene copolymer (PVdF-HFP) with a flexible structure, Li6PS5Cl (LPSCl) powder of the sulfur-silver-germanium ore type, and lithium perchlorate salt (LiClO4) were prepared into sulfide gel composite electrolyte films (GCEs) via a thermosetting process. The experimental results showed that the gel composite electrolyte with 1% LPSCl in the PVdF-HFP matrix exhibited an ionic conductivity as high as 1.27 × 10-3 S·cm-1 at 25 °C and a lithium ion transference number of 0.63. The assembled LiFePO4||GCEs||Li batteries have excellent rate (130 mAh·g-1 at 1 C and 54 mAh·g-1 at 5 C) and cycling (capacity retention was 93% after 100 cycles at 0.1 C and 80% after 150 cycles at 0.2 C) performance. This work provides new methods and strategies for the design and fabrication of solid-state batteries with high ionic conductivity and high specific energy.

Stabilizing a Li1.3Al0.3Ti1.7(PO4)3/Li metal anode interface in solid-state batteries with a LiF/Cu-rich multifunctional interlayer.

Li1.3Al0.3Ti1.7(PO4)3 (LATP) has attracted much attention due to its high ionic conductivity, good air stability and low cost. However, the practical application of LATP in all-solid-state lithium batteries faces serious challenges, such as high incompatibility with lithium metal and high interfacial impedance. Herein, a CuF2 composite layer was constructed at a Li/LATP interface by a simple drop coating method. CuF2 in the interlayer reacts with lithium metal in situ to form a multifunctional interface rich in Cu and LiF. The multifunctional layer not only brings about close interfacial contact between LATP and Li metal, but also effectively prevents the electrochemical reaction of LATP with Li metal, and suppresses the electron tunneling and dendrite growth at the interface. The interfacial resistance of Li/CuF2@LATP/Li symmetric batteries is significantly reduced from 562 to 92 Ω, and the critical current density is increased to 1.7 mA cm-2. An impressive stable cycle performance of over 6000 h at 0.1 mA cm-2/0.1 mA h cm-2, 2200 h at 0.2 mA cm-2/0.2 mA h cm-2 and 1600 h at 0.3 mA cm-2/0.3 mA h cm-2 is achieved. Full batteries of LiFePO4/CuF2@LATP/Li also show a high capacity retention ratio of 80.3% after 540 cycles at 25 °C. This work provides an effective and simple composite layer solution to address the interfacial problem of Li/LATP.

Porous hybrid encapsulation enables high-rate lithium storage for a micron-sized SiO anode.

Establishing a durable interfacial layer between an electrode and electrolyte to enable micron-sized silicon-based lithium-ion battery (LIB) anodes to achieve superior electrochemical performance is highly desired. Recent studies have shown that heterogeneous encapsulation with enhanced ion/electron transport is an effective strategy. However, the structural design of the existing hetero-coated interface lacks a reasonable ion/electron transport channel, resulting in high interfacial impedance. Herein, we designed a heterogenous MXene-mesoporous polypyrrole (mPPy) encapsulation layer onto micron-sized SiO particles. The MXene coating layer functions as a bridging interface that can build a strong chemical link to internal SiO via covalent bonding, thus reinforcing interfacial charge transfer rate. Meanwhile, it forms a dynamic connection with the outer mPPy through hydrogen bonding, which contributes to high interfacial Li+ concentration and ion/electron coupling transport rate. Accordingly, the as-prepared SiO@MXene@mPPy anode delivers a boosted specific capacity of 673.9 mA h g-1 at 2 A g-1 after 1000 cycles and high-rate capability of 777.4 mA h g-1 at 5 A g-1. Further, electrochemical kinetic analysis indicates that the MXene@mPPy coating layer shows a pseudocapacitance controlled Li storage mechanism, thereby displaying improved high-rate capability. This porous hybrid encapsulation strategy offers new possibilities for a micron-sized SiO anode to achieve an excellent performance.

Interfacial Degradation Processes in Solid-State Batteries during High Temperature Processing and the Mitigation Strategies

Garnet-type solid electrolytes have been extensively investigated in recent times as potential candidates for solid-state batteries. Among them, garnets with nominal composition Li7La3Zr2O12(LLZO) have received particular attention due to their high Li-ion conductivity (10-3 Scm-1) at room temperature and chemical stability against metallic lithium besides possessing a large electrochemical window >5V.[1] Despite of striking properties, LLZO suffers from several challenges such as interfacial instability with cathodes, e.g., LCO, during high temperature processing, resulting in a huge interface resistance, which is one of the fundamental reasons for the failure of solid-state batteries based on LLZO.[2-4] So far, the high interfacial impedance has been related to LLZO|LCO interface decomposition occurring due to diffusion of Co across the cathode-electrolyte interface. Herein, we investigated the hypothesis that interfacial degradation originate from the incorporation of Co into the LLZO lattice. The solubility limit of Co is determined to be 0.16 per formula unit, whilst the concentrations beyond promote phase transition (cubic LLZO-to-tetragonal LLZO). We investigated in detail the temperature-dependent Co diffusion into LLZO and concluded that detrimental cross diffusion could take place at any relevant process condition. Besides, the optimal protective Al2O3 coating thickness for relevant temperatures was studied, which allowed to create a process diagram to provide mitigation strategies towards enabling stable LCO|LLZO interface in all-solid-state batteries. Keywords: Solid-state batteries, Interfaces, cross diffusion, interfacial degradation AcknowledgementsD.R. acknowledges financial support by the Austrian Federal Ministry for Digital and Economic Affairs, the National Foundation for Research, Technology and Development and the Christian Doppler Research Association (Christian Doppler Laboratory for Solid-State Batteries). D.R. and J. F. acknowledges financial support by the Austrian Science Fund (FWF) in the frame of the project InterBatt (P 31437). D.K. acknowledges funding by the European Union’s Horizon 2020 Research and Innovation Programme (Grant No. 823717, project “ESTEEM3”) and by the Zukunftsfond Steiermark.Reference[1] Murugan, R., Thangadurai, V. and Weppner, W., 2007. Fast Lithium Ion Conduction in Garnet‐type Li7La3Zr2O12. Angew. Chemie. Int. Edt., 46(41), 7778-7781.[2] Chen, X., Xie, J., Zhao, X., & Zhu, T., 2021. Electrochemical Compatibility of Solid‐State Electrolytes with Cathodes and Anodes for All‐Solid‐State Lithium Batteries: A Review. Adv. Energy Sustain. Res., 2(5), 2000101.[3] Sakuda, A., Hayashi, A., Tatsumisago, M., 2010. Interfacial Observation Between LiCoO2 Electrode and Li2S-P2S5 Solid Electrolytes of All-Solid-State Lithium Secondary Batteries Using Transmission Electron Microscopy. Chem. Mater., 22(3), 949–956.[4] Ihrig, M., Kuo, L.Y., Lobe, S., Laptev, A.M., Lin, C.A., Tu, C.H., Ye, R., Kaghazchi, P., Cressa, L., Eswara, S. and Lin, S.K., 2023. Thermal Recovery of the Electrochemically Degraded LiCoO2/Li7La3Zr2O12: Al, Ta Interface in an All-Solid-State Lithium Battery. ACS Appl. Mater. Interfaces.

Rationally Designed in-Situ Gelled Polymer-Ceramic Hybrid Electrolyte Enables Superior Performance and Stability in Quasi-Solid-State Lithium-Sulfur Batteries

Despite boasting giant leaps in performance improvement over the years, the current commercial standard, Li-ion batteries, are fast approaching their theoretical limits. Meanwhile, Lithium-Sulfur (Li-S) batteries offering ultra-high theoretical energy density (～2600 Whkg-1), cost-effectiveness, and nontoxicity are being seen as promising alternatives. Despite their plentiful advantages, the practicality of Li-S batteries has been largely stymied by several challenges: a) deleterious polysulfide dissolution and ‘shuttle effect’, b) significant volume change of S cathodes during cycling, c) safety concerns with flammable traditional glyme-based electrolyte, and d) the instability of Li anode. To mitigate these challenges, researchers have explored all-solid-state electrolytes, but their poor Li-ion conductivity, high interfacial impedance, and need for expensive, exotic materials and complex fabrication procedures severely limit their practical application.To overcome these challenges, we propose an in-situ gelled polymer-ceramic hybrid silsesquioxane-based electrolyte system. The gelled matrix, thermally crosslinked post cell fabrication, immobilizes the glyme-based liquid electrolyte and exhibits high liquid-like ionic conductivities (1.03 mS.cm-1), low interfacial impedance, and high oxidative potential (>4.5V vs. Li/Li+) . In this study, in addition to vastly decreased flammability, we report superior Li-ion conductivity compared to state-of-art solid-state Li-S electrolytes. This high ionic conductivity translated to a significantly improved specific capacity of 1050 mAh.gS-1 at 0.2 C, elevated Coulombic efficiencies (>98.5%), and elevated rate kinetics. The gelled electrolytes exhibited stable cycling in a large temperature range (-10oC - 60 oC). Moreover, polysulfide permeation studies and subsequent DFT calculations revealed that the gelled electrolyte exhibited strong chemical absorptivity to lithium polysulfides due to the polar silsesquioxane core, which translated to superior capacity retention (>80% over 200 cycles). Further, post- mortem XPS characterization studies revealed the formation of stable SEI at the anode and cathode, and SEM of cycled anodes showed reduced dendritic formations. Finally, the electrolyte was tested in practical pouch cell architecture, and the cells demonstrated excellent reliability even under mechanical stress. This work successfully reports a robust, rationally designed gelled electrolyte system for developing safe and high-performance quasi-solid state Li-S batteries.

(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.

Electrospun Perovskite Nanofiber/Poly(vinylidene fluoride-cohexafluoropropylene) Quasi-Solid-State for Lithium-Metal Batteries

Solid-state lithium-metal batteries (SSLMBs) with a composite solid electrolyte (CSE) have great potential for achieving both high energy density and high safety and are thus promising next-generation energy storage devices. Nevertheless, the key bottleneck issues are a high electrode/electrolyte interface resistance and the limited Li+ conductivity of the solid electrolyte. A free-standing CSE consisting of Li0.33La0.557TiO3 (LLTO) nanofibers, poly(vinylidene fluoride-co-hexafluoropropylene (PVDF-HFP), and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) is developed for room-temperature SSLMB applications. First, the calcination temperature for the electrospun LLTO precursor is optimized. The effects of the LLTO filler fraction and the morphology (spherical vs. fibrous) on CSE conductivity are examined. Furthermore, a succinonitrile interlayer (SNI), which is composed of succinonitrile, fluoroethylene carbonate, and LiTFSI, is developed to lower the high interfacial impedance. Compared to a conventional ester-based interlayer (EBI), SNI effectively decreases the Li//CSE interfacial resistance and suppresses unfavorable interfacial side reactions. The derived LiF- and CF x -rich protective layer on the Li electrode surface prevents the accumulation of dead Li and the excessive formation of SEI. Importantly, the dehydrofluorination reactions of PVDF-HFP are adequately mitigated, and a highly conductive and stable Li//CSE interface is achieved owing to SNI. Accordingly, both Li//CSE@SNI//Li and Li//CSE@SNI//LiFePO4 cells exhibit superior charge-discharge properties and cyclability to those of an EBI counterpart. A simple and low-cost interface modification strategy to enhance the performance of SSLMBs is proposed in this paper.

A high ion conductive solid electrolyte film and interface stabilization strategy for solid-state Li-S battery

Lithium-sulfur (Li-S) batteries are regarded as a potential next-generation electrochemical energy storage technology. However, polysulfide shuttle effect and lithium dendrite growth always worsen the battery's cycling performance, especially, the safety problem of liquid electrolyte has also become a major challenge to the development and application of Li-S batteries. Herein, a high ion conductive poly(1,3-dioxolane) solid electrolyte film (PDOL) was introduced in Li-S battery, which hinders the shuttle of polysulfides, and forms a uniform LiF protective layer on the lithium metal contact surface to inhibit the growth of lithium dendrites. Meanwhile, the problem of high interfacial impedance in solid-state Li-S batteries was also solved by adding a trace amount of flexible organic ether electrolyte to the solid electrolyte/electrode interface. The assembled quasi-solid-state S/PDOL/Li cell shows low interfacial impedance less than 75 Ω and can be stably cycled over 500 times at 0.1 C. This rigid-flexible solid electrolyte design method provides a practical idea for the development of high-performance solid-state Li-S batteries.

Advancements, Challenges, and Prospects in Rechargeable Solid‐State Lithium‐Air Batteries

AbstractSolid‐state lithium‐air batteries (SSLABs) are attracting widespread research interest as emerging energy storage systems with ultra‐high theoretical energy density. However, due to their relatively short development history, the practical capacity and cyclic performance of SSLABs still fail to meet application requirements. The selection of solid electrolytes and the design and optimization of air cathodes are key factors for developing high‐performance solid‐state lithium‐air batteries. In this review, we focus on recent scientific advances and challenges in SSLABs, providing a comprehensive overview of solid electrolytes, air cathodes, and interface issues. Strategies such as electrolyte modification, composite cathodes, interface engineering, and the addition of catalysts which have been effective in addressing issues related to low ionic conductivity of electrolytes, high interfacial impedance, sluggish kinetics of electrochemical reactions, and poor cycling stability, were reviewed and discussed. Furthermore, this review also discusses the prospects of SSLABs, aiming to inspire and provide references for the development of solid‐state lithium‐air batteries, as well as other metal‐air batteries.

Synergetic Monitoring of both Physiological Pressure and Epidermal Biopotential Based on a Simplified on-Skin-Printed Sensor Modality.

Flexible electronic sensors show great potential for health monitoring but are usually limited to single sensing functionality. To enrich their functions, complicated device configurations, sophisticated material systems, and preparation processes are typically involved, obstructing their large-scale deployment and widespread application. Herein, to achieve a good balance between simplicity and multifunctionality, a new paradigm of sensor modality for both mechanical sensing and bioelectrical sensing is presented based on a single material system and a simple solution processing approach. The whole multifunctional sensors are constructed with a pair of highly conductive ultrathin electrodes (WPU/MXene-1) and an elastic micro-structured mechanical sensing layer (WPU/MXene-2), with the human skin serving as the substrate for the whole sensors. The resultant sensors show high pressure sensitivity and low skin-electrode interfacial impedance, enabling to synergetically monitor both physiological pressure (e.g., arterial pulse signals) and epidermal bioelectrical signals (including electrocardiograph and electromyography). The universality and extensibility of this methodology to construct multifunctional sensors with different material systems are also verified. This simplified sensor modality with enhanced multifunctionality provides a novel design concept to construct future smart wearables for health monitoring and medical diagnosis.

Stable Interface between Sulfide Solid Electrolyte and Room-Temperature Liquid Lithium Anode.

Sulfide solid electrolytes (SEs) are considered to be some of the most promising SEs for commercialization due to their high ionic conductivity, good mechanical ductility, and good interfacial contact with electrodes. The Ohmic resistance of solid-state batteries assembled with sulfide SEs is significantly reduced, but the problem of high interfacial impedance due to poor interfacial chemical/electrochemical stability between sulfide SEs and the electrodes is serious. Therefore, the formation and evolution of the electrode/sulfide SE interface during battery assembly and cycling have a crucial impact on the performance of the battery, which is one of the key issues to be solved in battery commercialization. Herein, a variety of compatible interface protective layers, including PEO and β-Li3PS4/S, are obtained between sulfide SEs and ether-based room-temperature liquid lithium anodes for long-term stable cycling of >1000 h. Such a technical method for stabilizing the solid-liquid interface between a sulfide SE and an organic liquid lithium anode successfully solves the key problem of interfacial side reactions, making this battery configuration safe and stable for long-cycle operation.

A Composite of Hierarchical Porous MOFs and Halloysite Nanotubes as Single-Ion-Conducting Electrolyte Toward High-Performance Solid-State Lithium-Ion Batteries.

Metal-organic frameworks (MOFs), as a promising rechargeable electrochemical energy storage material have emerged in the field of solid-state lithium batteries. However, low ionic conductivity and high interfacial impedance still severely hamper the application of MOF-based solid-state electrolytes (SSE). In this work, a novel hierarchical porous H-ZIF-8 solid-state electrolyte (SSE) material is harvested through the in situ growth of zinc nitrate hydroxide nanosheets, expressing excellent ion conductivity of 1.04 × 10-3 Scm-1 and Li+ -transference number of 0.71. Moreover, the morphology and structure of H-ZIF-8 is further optimized to obtain a composite H-ZIF-8/HNT by decorating halloysite nanotubes (HNT). Notably, functionalized H-ZIF-8/HNT as an electrolyte presents obvious enhancement on electrochemical properties: higher ionic conductivity of 7.74 × 10-3 Scm-1 , better single-ion transmittability ( = 0.84), good interfacial compatibility as well as excellent rate performance. More importantly, the Li/LiFePO4 battery equipped with H-ZIF-8/HNT SSE has efficient lithium-dendrite suppression and up to 84% capacity retention (104.16mAhg-1 ) after 200 times galvanostatic charge/discharge cycles. This work enriches the solid-state lithium-ion composite electrolyte materials, opening an entirely new way for enhancing electrochemical performance.

Boron‐Based High‐Performance Lithium Batteries: Recent Progress, Challenges, and Perspectives

AbstractWith the development of energy storage technology, the demand for high energy density and high security batteries is increasing, making the research of lithium battery (LB) technology an extremely important pursuit. However, the poor structural stability of electrode materials, high interfacial impedance between electrolyte and electrode, and the growth of lithium dendrites have seriously hindered the commercialization of LBs. Recently, due to their unique electronic structures and hybrid forms, boron‐based materials have been widely used in different LB components, such as electrodes, electrolytes, separators, additives, and binders, to resolve these problems. Here, a basic understanding of boron and boron‐based materials is first introduced. Subsequently, the recent research progress on the application of boron in each component of the LB is summarized, aiming to understand the hybrid forms of boron and their potential for use in LB materials. Finally, some new strategies and perspectives on the application of boron in LB materials are proposed. Here, the aim is to provide a clear insight on the study of boron in energy storage materials and contribute to the promotion of further research in this area.

In situ Synthesis of Gel Polymer Electrolytes for Lithium Batteries

AbstractGel polymer electrolytes (GPEs) are considered as a promising solution to replace organic liquid electrolytes for safer lithium (Li) batteries due to their high ionic conductivity comparable to liquid electrolytes, no risk of leakage, and high flexibility. However, poor interfacial contact between electrodes and GPEs leads to high interfacial impedance and unsatisfactory electrochemical performance. The emerging in situ synthesized GPEs can fully infiltrate into porous electrodes and form intimate interfaces, improving interfacial contact and electrochemical performance. This perspective covers recent advances of in situ GPEs in design, synthesis, and applications in lithium (Li) batteries. Polyester and polyether‐based GPEs are mainly discussed followed by a brief introduction of GPEs with other polymer matrices, such as poly(ionic liquid)s, cyanoethyl polyvinyl alcohol, poly(vinyl acetal) and single‐ion conductors. Then, the recent progress in Li batteries using in situ GPEs are summarized, including Li‐ion battery, Li‐metal battery, Li‐sulfur battery, and Li‐air battery. Finally, the remaining challenges and future perspectives of in situ GPEs are discussed. We hope this perspective can offer guidance for in situ synthesis of GPEs and facilitate their applications in high‐performance Li batteries.

Sandwich-Structured Quasi-Solid Polymer Electrolyte Enables High-Capacity, Long-Cycling, and Dendrite-Free Lithium Metal Battery at Room Temperature.

The insufficient ionic conductivity, limited lithium-ion transference number (tLi +), and high interfacial impedance severely hinder the practical application of quasi-solid polymer electrolytes (QSPEs). Here, a sandwich-structured polyacrylonitrile (PAN) based QSPE is constructedin which MXene-SiO2 nanosheets act as a functional filler to facilitate the rapid transfer of lithium-ion in the QSPE, and a polymer and plastic crystalline electrolyte (PPCE) interface modification layer is coated on the surface of the PAN-based QSPE of 3wt.% MXene-SiO2 (SS-PPCE/PAN-3%) to reduce interfacial impedance. Consequently, the synthesized SS-PPCE/PAN-3% QSPE delivers a promising ionic conductivity of ≈1.7mScm-1 at 30°C, a satisfactory tLi + of 0.51, and a low interfacial impedance. As expected, the assembled Li symmetric battery with SS-PPCE/PAN-3% QSPE can stably cycle more than 1550h at 0.2 mA cm-2 . The Li||LiFePO4 quasi-solid-state lithium metal battery (QSSLMB) of this QSPE exhibits a high capacity retention of 81.5% after 300 cycles at 1.0C and at RT. Even under the high-loading cathode (LiFePO4 ≈10.0mgcm-2 ) and RT, the QSSLMB achieves a superior area capacity and good cycling performance. Besides, the assembled high voltage Li||NMC811(loading≈7.1 mgcm-2 ) QSSLMB has potential applications in high-energy fields.

Role of Scaffold Architecture and Excess Surface Polymer Layers in a 3D‐Interconnected Ceramic/Polymer Composite Electrolyte

Abstract3D‐interconnected ceramic/polymer composite electrolytes offer promise to combine the benefits of both ceramic and polymer electrolytes. However, an in‐depth understanding of the role of the ceramic scaffold's architecture, and the associated polymer/ceramic interfaces on the electrochemical properties of such composite electrolytes is still incomplete. Here, these factors are systematically evaluated using an interconnected composite electrolyte with a tunable and well‐defined architecture. The ionic conductivity of the ceramic scaffold is strongly dependent on its porosity and tortuosity, as demonstrated experimentally and via theoretical modeling. The connectivity of the ceramic framework avoids the high interfacial impedance at the polymer/ceramic electrolyte interface within the composite. However, this work discovers that the interfacial impedance between the bulk composite and excess surface polymer layers of the composite membrane dominates the overall impedance, resulting in a 1–2 order drop of ionic conductivity compared to the ceramic scaffold. Despite the high impedance interfaces, an improved Li+ transference number is found compared to the neat polymer (0.29 vs 0.05), attributed to the ceramic phase's contributions toward ion transport. This leads to flatter overpotentials in lithium symmetric cell cycling. These results are expected to guide future research directions toward scalable manufacturing of composite electrolytes with optimized architecture and interfaces.

Achieving stable interface for lithium metal batteries using fluoroethylene carbonate-modified garnet-type Li6.4La3Zr1.4Ta0.6O12 composite electrolyte

Composite polymer electrolytes (CPEs) with Li6.4La3Zr1.4Ta0.6O12 (LLZTO) ceramic oxide electrolytes are attracting significant interest because of the merits of LLZTO. However, inadequate solid-solid contact between electrolytes and electrodes invariably results in high interfacial impedance, which is harmful to CPEs' performance. Herein, fluoroethylene carbonate (FEC) additive which possesses excellent ability in guiding uniform Li+ deposition and suppressing Li dendrite growth was introduced into the electrolyte, and novel CPEs were successfully prepared. It shows a broad electrochemical window of 5.2 V (vs. Li+/Li), low interface impedance, and a high lithium ion migration number of 0.62. As a result, the assembled symmetrical Li/PHTL-FEC-LLZTO/Li cells can run stably for over 500 h at 0.2 mA cm–2. Moreover, the Li metal battery with LiFePO4 (LFP) cathode shows superior cyclic stability with a high initial capacity of 132.9 mAh g–1, and a large retention of 88.5% after 200 cycles at 0.5 C. This excellent electrochemical performance of the battery can be attributed to the employment of FEC additives, which endows promising potential in reducing the interface impedance, promoting lithium uniform deposition, and stabling interface performance in the electrolyte.

Press-N-Go On-Skin Sensor with High Interfacial Toughness for Continuous Healthcare Monitoring.

On-skin electronic sensors are demanded for healthcare monitoring such as the continuous recording of biopotential and motion signals from patients. However, the mechanical mismatches and poor interface adhesion at the skin/sensor interfaces always cause high interfacial impedance and artifacts, frequent interfacial failure, and unexpected depletion of the device, which significantly limit the performance of the sensors. We here develop an on-skin sensor based on a conductive pressure-sensitive tape, which is assembled from supramolecular dual-cross-linked hydrogel composites. Both covalent and noncovalent cross-links in the hydrogel networks could harvest high flexibility, pressure-sensitive adhesion, and high interfacial toughness altogether, enabling a convenient "Press-N-Go" application of the sensor on human skin without additional pre/post-treatment on the skin or the senor. The high conformability and low resistivity of the tape can sustainably lower the interfacial impedance and thus improve signal quality in various measurement conditions. Our design provides a feasible path to develop interface-toughened on-skin electronics, which is desired in dynamic human-machine interfaces.

In-situ constructed SnO2 gradient buffer layer as a tight and robust interphase toward Li metal anodes in LATP solid state batteries

Li1.3Al0.3Ti1.7(PO4)3 (LATP), of much interest owing to its high ionic conductivity, superior air stability, and low cost, has been regarded as one of the most promising solid-state electrolytes for next-generation solid-state lithium batteries (SSLBs). Unfortunately, the commercialization of SSLBs is still impeded by severe interfacial issues, such as high interfacial impedance and poor chemical stability. Herein, we proposed a simple and convenient in-situ approach to constructing a tight and robust interface between the Li anode and LATP electrolyte via a SnO2 gradient buffer layer. It is firmly attached to the surface of LATP pellets due to the volume expansion of SnO2 when in-situ reacting with Li metal, and thus effectively alleviates the physical contact loosening during cycling, as confirmed by the mitigated impedance rising. Meanwhile, the as-formed SnO2/Sn/LixSn gradient buffer layer with low electronic conductivity successfully protects the LATP electrolyte surface from erosion by the Li metal anode. Additionally, the LixSn alloy formed at the Li surface can effectively regulate uniform lithium deposition and suppress Li dendrite growth. Therefore, this work paves a new way to simultaneously address the chemical instability and poor physical contact of LATP with Li metal in developing low-cost and highly stable SSLBs.