Composite Electrolyte Membranes Research Articles

High performance solid state lithium batteries with a continuous homogeneous Li+ transmission channels

Solid state lithium batteries have been encountering a bottle neck of high solid-solid interface resistance of the membrane/electrode assembly, which is one industrial pain point. Herein, the composite solid electrolyte materials were designed and prepared to act as the double functions of solid state electrolyte membrane and the electrode binder for constructing a continuous homogeneous Li+ transmission channels with high compatibility and ionic conductivity. Firstly, dopamine was oxidized and self-polymerized on the surface of polyvinylidene fluoride hexafluoropropylene (PVDF-HFP) to form a polydopamine (PDA) active layer, and the zwitterionic betaine sulfonate (SB) was chemically grafted onto the PDA active layer by Michael addition reaction. Secondly, the composite solid electrolyte materials were prepared by mixing the resultant SB-modified PVDF-HFP was mixed with different contents (0 %, 10 %, 20 %, 30 %) of Li6.75La3Zr1.75Ta0.25O12 (LLZTO) and 20 % bis(trifluoromethane) sulphonyl lithium (LiTFSI). Finally, a series of composite solid electrolyte membranes were prepared by scraping method and labeled as 0%LLZTO/SB-PVDF-HFP/LiTFSI, 10%LLZTO/SB-PVDF-HFP/LiTFSI, 20 %LLZTO/SB-PVDF-HFP/LiTFSI, 30%LLZTO/SB-PVDF-HFP/LiTFSI, respectively. As expected, the cell with optimal 20 %LLZTO/SB-PVDF-HFP/LiTFSI as the solid electrolyte membrane and the electrode binder delivered the reversible capacity of 135.2 mAh/g at 1.0C and maintained high capacity retention of 94.8 % for 200 cycles. The construction of the continuous and homogeneous ion transmission channels should be responsible for high Li-storage performances by improving the interface compatibility of the membrane/electrode assembly and promoting the Li+ transmission.

Building Bulk and Interface Dual Fast Li+ Conducting Pathway in Composite Solid Polymer Electrolyte Membrane for All–Solid–State Lithium–Metal Batteries

AbstractSolid polymer electrolytes (SPEs) are considered a promising solution to the safety problems of lithium‐ion batteries (LIBs) using liquid electrolytes. However, the high crystallinity and low ionic conductivity hinder the practical application of SPEs. Herein, we design a composite solid polymer electrolyte with a dual fast Li+ conducting pathway in bulk and interface by incorporating highly Li+ conductive ceramic Li6.4Ga0.2La3Zr2O12 (LGLZO) in polyethylene oxide (PEO)/Li–bis (trifluoromethanesulfonyl) imide (LiTFSI) system. Compared to Li6.5La3Zr1.5Ta0.5O12 (LLZTO), LGLZO provides better Li+ conductivity; therefore, a fast Li+ conducting pathway will form in the bulk of LGLZO nanofillers. Besides, LGLZO nanofiller accelerates the dissociation of LiTFSI and benefits the transfer of free Li+ through the SPEs near the LGLZO surface, forming another interface fast Li+ conducting pathway in the SPEs. Benefits from the dual fast Li+ pathway design, the composite electrolyte membrane with 15 wt % LGLZO nanoparticles presents a high ionic conductivity of 8.0×10−4 S cm−1 at 60 °C. The Li−Li symmetric cells with optimized content LGLZO show good cycling stability (no short circuit even after 1000 h), and the all–solid Li/LiFePO4 batteries exhibit excellent cycling performance (remained 154 mAh g−1 after 500 cycles at 0.2 C under 60 °C).

Self-supported flexible organic electrochemical synaptic transistors on self-healing composite electrolyte membranes

A variety of organic electrochemical transistors have been recently developed; however, their self-healing performance has been largely ignored. In this study, we propose the use of a lithium-ion composite electrolyte membrane as a dielectric layer and the use of poly(3-hexylthiophene) (P3HT) as a channel layer to fabricate flexible self-supporting organic synaptic transistors. A variety of synaptic behaviors were emulated within the proposed organic synaptic transistors. By leveraging the self-healing features of polymer electrolytes, along with cross-linking reactions and low-resistance lithium-ion transmission, the device maintained its electrical performance. Testing involving different curvatures also revealed the device's potential for use in flexible electronics. Significantly, due to the device's self-healing ability, consistent dataset recognition rates were sustained. This work highlights its vast prospects in the field of flexible and wearable electronics.

Sulfonated poly(ether ether ketone)-Protic ionic Liquid-Based anhydrous Proton-Conducting composite polymer electrolyte membranes for High-Temperature fuel cell applications

A high-temperature polymer electrolyte membrane fuel cell (PEMFC) has enormous potential to produce clean energy with minimal environmental pollution along with high energy density and conversion efficiency. In the present work, anhydrous proton-conducting polymer electrolyte membranes for prospective high-temperature fuel cell application were successfully prepared using different protic ionic liquids (PILs) and sulfonated poly(ether ether ketone) (SPEEK). The protic ionic liquids (PILs), 2-hydroxyethylammonium formate, diethylmethyl ammonium triflate, 1-ethylimidazolium bis(trifluoromethylsulfonyl)imide, 1,2-dimethyl imidazolium bis(trifluoro methylsulfonyl)imide, and diethylmethylammonium methanesulfonate were selected based on their favorable physicochemical properties. The effect of the incorporation of the PIL on the structural, thermal, and electrical transport properties of the composite SPEEK polymer electrolyte membranes was studied. The prepared polymer electrolyte membranes (PEMs) were characterized using Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffractometry (XRD), and electrochemical impedance spectroscopy (EIS) techniques. FTIR results indicated an interaction between the PIL and the SPEEK, which resulted in homogeneous and flexible membranes. The DSC results confirmed good miscibility and elucidated plasticizing effect of the incorporated PIL on the SPEEK polymer matrix. All the PEMs showed good thermal stability and high-temperature anhydrous proton conductivity, achieving best proton conductivity, ≈8 × 10–3 S cm−1 at 120 °C and low activation energy ≈0.26 eV, making it suitable for prospective high-temperature PEMFC applications.

Dual polymer (PVDF-HFP and PES) matrix / Li6.4La3Zr1.4Ta0.6O12 composite solid electrolyte with good stability for solid state lithium ion batteries operating at different temperatures

Solid state lithium-ion batteries (SSLIBs) with high safety and high energy density are promising novel energy storage devices. However, the performance of SSLIBs would descend under a wide work temperature range. A flexible ceramic-polymer composite solid electrolyte membrane was created by solution casting to obtain good stability of SSLIBs at different temperatures. The PVDF-HFP-PES-LiClO4-Li6.4La3Zr1.4Ta0.6O12 (LLZTO) composite solid electrolyte shows excellent electrochemical performances in the temperature range of 20 to 60 oC. The ionic conductivity of PVDF-HFP-PES-LiClO4-LLZTO (PPLL) is 4.26 × 10-4, 4.97 × 10-4, 5.26 × 10-4, 5.59 × 10-4 and 5.97 × 10-4 S cm-1 at 20, 30, 40, 50 and 60 oC, respectively. The PPLL was employed in LiFePO4 (LFP)/PPLL/Li batteries, and their properties were tested at 0.2 C. The test results show that the LFP/PPLL/Li battery has a good charge-discharge, rate, and cyclic performance at 20 - 60 oC. After 150 cycles with 0.2C at 30 oC and 60 oC, the capacity retention rates of 75.6% and 86.4%, respectively. This work provides an effective strategy for designing and preparing SSLIBs.

Development of a Novel Composite Polymer Electrolyte Membrane for Application as a Separator in a Dual Chamber Microbial Fuel Cell

Development of a Novel Composite Polymer Electrolyte Membrane for Application as a Separator in a Dual Chamber Microbial Fuel Cell

Hot-Pressing Enhances Mechanical Strength of PEO Solid Polymer Electrolyte for All-Solid-State Sodium Metal Batteries.

Poly(ethylene oxide) (PEO)-based solid polymer electrolytes (SPEs) are widely utilized in all-solid-state sodium metal batteries (ASSSMBs) due to their excellent flexibility and safety. However, poor ionic conductivity and mechanical strength limit its development. In this work, an emerging solvent-free hot-pressing method is used to prepare mechanically robust PEO-based SPE, while sodium superionic conductors Na3 Zr2 Si2 PO12 (NZSP) and NaClO4 are introduced to improve ionic conductivity. The as-prepared electrolyte exhibits a high ionic conductivity of 4.42×10-4 S cm-1 and a suitable electrochemical stability window (4.5V vs Na/Na+ ). Furthermore, the SPE enables intimate contact with the electrode. The Na||Na3 V2 (PO4 )3 @C ASSSMB delivers a high-capacity retention of 97.1% after 100 cycles at 0.5 C and 60°C, and exhibits excellent Coulombic efficiency (CE) (close to 100%). The ASSSMB with the 20µm thick electrolyte also demonstrates excellent cyclic stability. This study provides a promising strategy for designing stable polymer-ceramic composite electrolyte membranes through hot-pressing to realize high-energy-density sodium metal batteries.

Composite polymer electrolyte based on poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) for solid-state batteries

Using solid-state electrolytes (SSEs) with excellent thermal and electrical stability to replace liquid electrolytes, and assembling solid-state lithium-ion batteries (SSLIBs) is considered the best solution to these safety issues. However, it is difficult for a single electrolyte to have the characteristics of high ionic conductivity, low interface resistance, and high stability of the counter electrode at the same time. In this work, the composite polymer electrolyte membrane (CPE) of inorganic Li1.3Al0.3Ti1.7(PO4)3 (LATP) and organic poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) polymer was successfully prepared by traditional casting method. The addition of LATP (10 wt %) ceramic powder makes CPE membrane (CPE-10) exhibit excellent electrochemical performance: the lithium-ion transference number and electrochemical window are as high as 0.60 and 4.94 V, respectively. Moreover, the CPE-10 showed excellent Li-metal stability, thereby enabling the Li–Li symmetric cells to stably run for over 300 h at 0.1 mA/cm2 with effective lithium dendrite inhibition. When paired with a high-voltage LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode, the Li/CPE-10/NCM622 cell exhibited excellent electrochemical performance: the highest specific discharge capacity of 152 mAh/g could be conducted at 0.2C after 50 cycles corresponding to 100% Coulombic efficiencies. The prepared CPE-10 demonstrates excellent electrochemical performance, providing an effective design strategy for SSLMBs.

All-Perfluorosulfonated-Ionomer Composite Membranes Containing Blow-Spun Fibers: Effect of a Thin Fiber Framework on Proton Conductivity and Mechanical Properties.

In this study, thin fiber composite polymer electrolyte membranes (PEMs) were prepared using short side-chain perfluorosulfonic acid (PFSA) ionomers, Aquivion, to create composite PEMs with improved proton conductivity and improved mechanical properties. PFSA thin fiber webs prepared by blow spinning and successive hot pressing were used as the porous substrate. Herein, PFSA ionomers were used for both the substrate and the matrix of the composite PEMs, and their structures, properties, and fuel cell performance were characterized. By adding the PFSA thin fiber webs to the matrix, the proton conductivity was enhanced and the mechanical properties were slightly improved. The prepared PFSA thin fiber composite PEM showed better FC performance than that of the pristine PFSA one for the high-temperature low-humidity condition in addition to the low-temperature high-humidity one. To the best of our knowledge, this is the first report on the all PFSA composite membranes containing a PFSA thin fiber framework.

Flexible Composite Electrolyte Membranes with Fast Ion Transport Channels for Solid-State Lithium Batteries.

Numerous endeavors have been dedicated to the development of composite polymer electrolyte (CPE) membranes for all-solid-state batteries (SSBs). However, insufficient ionic conductivity and mechanical properties still pose great challenges in practical applications. In this study, a flexible composite electrolyte membrane (FCPE) with fast ion transport channels was prepared using a phase conversion process combined with in situ polymerization. The polyvinylidene fluoride-hexafluoro propylene (PVDF-HFP) polymer matrix incorporated with lithium lanthanum zirconate (LLZTO) formed a 3D net-like structure, and the in situ polymerized polyvinyl ethylene carbonate (PVEC) enhanced the interface connection. This 3D network, with multiple rapid pathways for Li+ that effectively control Li+ flux, led to uniform lithium deposition. Moreover, the symmetrical lithium cells that used FCPE exhibited high stability after 1200 h of cycling at 0.1 mA cm-2. Specifically, all-solid-state lithium batteries coupled with LiFePO4 cathodes can stably cycle for over 100 cycles at room temperature with high Coulombic efficiencies. Furthermore, after 100 cycles, the infrared spectrum shows that the structure of FCPE remains stable. This work demonstrates a novel insight for designing a flexible composite electrolyte for highly safe SSBs.

Controlling the Potential of Affordable Quasi‐Solid Composite Gel Polymer Electrolytes for High‐Voltage Lithium‐Ion Batteries

AbstractThis study focuses on the development of a composite gel polymer electrolyte membrane (CGPEM) as a solution to address safety concerns arising from the reactivity of lithium metal and the formation of dendrites. The CGPEM integrates a solid polymer matrix, solid‐electrolyte LSiPS (Li10SiP2S12), with a plasticizer that countering the performance decline caused by sulfide solid electrolyte (SSE) interactions with the cathode. Poly ethylene oxide (PEO) emerges as a promising polymer matrix due to its flexibility, cost‐effectiveness, eco‐friendliness, solvability for Li‐salt, mechanical processing adaptability, adhesive strength, and ionic conductivity. Conductivity and processability of CGPEM were optimized through meticulous adjustment of liquid plasticizer concentration. The CGPEM′s chemical and electrochemical stability were systematically investigated using in‐situ electrochemical impedance spectroscopy (EIS) and distribution of relaxation times (DRTs). A lithium metal battery is constructed against a high voltage cathode and newly developed CGPEM. Impressively, the cell exhibited outstanding performance, maintaining a discharge capacity of around 146.22 mAh/g after 200 cycles, retaining 86.38 % of its initial capacity. The formation of a LiF‐rich interface layer near the lithium surface, a vital element in curbing CGPE degradation and dendritic growth, resulted in enhanced overall cell performance.

Micro Area Interface Wetting Structure with Tailored Li+-Solvation and Fast Transport Properties in Composite Polymer Electrolytes for Enhanced Performance in Solid-State Lithium Batteries.

To satisfy the demand for high safety and energy density in energy storage devices, all-solid-state lithium metal batteries with solid polymer electrolytes (SPE) replacing traditional liquid electrolytes and separators have been proposed and are increasingly regarded as one of the most promising candidates as next-generation energy storage systems. In this study, poly(vinylidene fluoride)-hexafluoropropylene/lignosulfonic acid (PVDF-HFP/LSA) composite polymer electrolyte (CPE) membranes with a micro area interface wetting structure were successfully prepared by incorporating LSA into the PVDF-HFP polymer matrix. The enhanced interaction between the polar functional group in LSA and the C═O in N-methylpyrrolidone (NMP) hinders the evaporation of solvent NMP, thus creating a micro area wetting structure, which offers a flexible region for the chain segment movement and enlarging the area of the amorphous zone in PVDF-HFP. From the results of IR and Raman spectroscopy, it was found that the presence of LSA induced unique ion transport channels created by the massive aggregated ion pair (AGG) and contact ion pair (CIP) of ion cluster structures composed of Li+ and multiple TFSI- and, at the same time, effectively reduced the crystallinity of the polymer electrolyte, hence further contributing to the Li+ diffusion. As a result, at a rate of 2 C, the Li|CPE-15|LiFePO4 solid-state battery delivers an initial discharge-specific capacity of 134.9 mAh g-1 and maintains stability with a retention of 84% during 400 charge-discharge cycles while the Li|CPE-0|LiFePO4 battery fails after only a few cycles at the same rate.

Preparation and Evaluation of Nafion/CeO2 Composite Electrolyte Membranes for Polymer Electrolyte Fuel Cells

Polymer electrolyte fuel cells (PEFCs) are increasingly applied to the vehicles (FCVs) toward the suppression of carbon dioxide emission. The larger FCVs requires the high power density to exceed the presumed temperature limit of 80 ℃, causing some issues of material durability and system performances. In particular, a commercial electrolyte membrane of Nafion occurs the decrease of proton conductivity at the high temperatures under an atmospheric pressure. To overcome this problem, our research group has developed a composite electrolyte membrane consisting of Nafion and Ta-TiO2 nanoparticles with a chain-like network structure. The composite electrolyte membrane improves a proton conductivity in a wide temperature range over 100 ℃ by the effect of hydrophilic surface of the oxide. In this study, the other candidate materials of CeO2, nanoparticles with highly hydrophilic surface rather than that of Ta-TiO2 was selected to try to improve the proton conductivity of the composite electrolyte membranes.The hydrophilic CeO2 nanoparticles with a chain-like network structure were prepared using flame oxide-synthesis method. The hydrophilic CeO2 nanoparticles were dispersed in a dispersion solvent in desired ratio. The dispersion was then added to 20 wt.% Nafion dispersion solution (DE2020 CS, Chemours Co.) neutralized with potassium hydroxide. The resulting dispersion was coated onto a die coater and dried using a hot air. The CeO2/Nafion composite membrane was then treated in high purified water with a sulfuric acid solution. The transmission electron microscopy (TEM) and water adsorption, and four-probe alternating current method was conducted to detect the microstructure, water uptake and proton conductivity of the composite membrane.TEM images confirmed that the CeO2 nanoparticles were highly dispersed in the composite membrane. The proton conductivity of the 3 wt.% CeO2 containing composite membrane was 2.1 times higher than that of commercial Nafion membrane (NRE211, Chemours Co.) at 80 ℃, 20% RH, and was 1.5 times higher than that at 80 ℃, 80% RH (Fig. 1). The proton conductivity of the 3 wt.% CeO2 containing composite membrane was found to be higher than that of the Nafion monolayer in each water uptake (Fig. 2), indicating that the morphology of the membrane might be changed by the adding of CeO2 oxide. Further research will be needed to examine the proton conductivity mechanism of this composite membrane, and fuel cell evaluations using this composite membrane. Figure 1

Binderless Sheet-Type Oxide-Sulfide Composite Solid Electrolyte for All-Solid-State Batteries

Lithium-ion batteries have been used as energy sources not only for small electronic devices but also for high-capacity and high-energy-density applications such as electric vehicles. However, the use of flammable organic liquid electrolytes in lithium-ion batteries has raised safety concerns in various applications. Therefore, solid-state batteries using flame-retardant inorganic materials are considered a more reasonable direction for future energy sources due to their high safety and high energy density. Solid electrolytes(SEs) are divided into oxide-based, sulfide-based, and polymer-based. Each solid electrolyte has its own advantages and disadvantages. Oxide-based solid electrolytes (e.g., Li7La3Zr2O12 (LLZO), Li3xLa2/3-xTiO3 (LLTO), Li1.3Al0.3Ti1.7(PO4)3 (LATP)) are air-stable and exhibit excellent electrochemical properties over a wide potential range. However, their high interfacial resistance may limit their practical application as batteries. Sulfide-based solid electrolytes (e.g., Li6PS5X (X=Cl, Br, I), Li10GeP2S12, (100-x)Li2S-xP2S5)) have high ionic conductivity, ductile properties, low interfacial resistance, and good room temperature workability. However, they are vulnerable to atmospheric instability, which can produce toxic gases such as H2S, and are relatively electrochemically unstable with Li metal. Polymer-based solid electrolytes, such as those made from polymers like PEO, PVDF, PAN, etc. that are compounded with other solid electrolytes (oxides, sulfides, etc.), offer the advantage of being able to form solid electrolyte membranes over large areas. But they have low ionic conductivity and weak mechanical properties of the polymer itself, limiting their practical application. To apply solid-state batteries to practical high-energy density energy storage devices such as electric vehicles, high ion conductivity, electrochemical stability, high mechanical properties, and large area formation of the electrolyte layer are essential. Solid electrolytes are mainly formed in powder form, and without a polymer binder, it is limited to apply as a film for large-capacity storage devices. Here, we fabricated a freestanding sheet-type Al-LLZO oxide-based solid electrolyte that forms a 3D network without a polymer material using an electrospinning method. In addition, we prepared a oxide-sulfide composite solid electrolyte membrane by impregnating LPSCl sulfide-based solid electrolyte into the Al-LLZO solid electrolyte sheet. As a result, This process removed the polymer and improved both the ionic conductivity and mechanical properties. Furthermore, it was possible to achieve both large-area and film characteristics without the need for a polymer.

Si-Drive European Project: Developing Crosslinked Polymer and Composite Membrane Electrolytes for Lithium-Based Batteries

Currently the main application of lithium ion batteries is in portable electronics, but new emerging applications such as electric cars require lower cost, improved cycle life, sustainability, safety and energy density.The ambition of Si-DRIVE European project is proposing next-generation batteries for electric cars built in Europe, designed to ensure recycling above 50%. Si-Drive battery will contain a Silicon anode, which has a high specific capacity, and a high voltage cathode without cobalt to reduce the cost and improve sustainability.As an alternative to conventional organic solvents, ionic liquids have been widely investigated over the years, due to their excellent properties in terms of safety and stability.The 1st generation of electrolytes for Si-Drive includes selected ionic liquids with high ionic conductivity and wide electrochemical stability. The 2nd generation of electrolytes combines the ionic liquids and the precursors of the polymer matrix in the formulation, in order to obtain crosslinked self-standing flexible films. The addition of ceramic super lithium ion conductors to obtain composite polymer electrolytes is also envisaged to improve the electrochemical stability window of the electrolyte.Here we present several different polymer electrolytes and semi interpenetrating polymer networks encompassing ionic liquids and ceramic materials having ionic conductivity > 10 mS/cm at 20 °C, which can be in situ-deposited and crosslinked on top of the electrodes, and combined to form bi-layered electrolyte membranes to tune the compatibility with the electrode materials. The cycling performance with different positive and negative electrodes at ambient temperature is also demonstrated. Acknowledgements: The Si-DRIVE project has received funding from the European Union’s Horizon 2020 Research&Innovation programme, under Grant Agreement 814464. References J.-Y. Hwang, S.-T. Myung, Y.-K. Sun, Chem. Soc. Rev. 46, 3529-3614 (2017)M. Falco, C. Simari, C. Ferrara, J.R. Nair, G. Meligrana, F. Bella, I. Nicotera, P. Mustarelli, M. Winter, C. Gerbaldi, Langmuir 35, 8210-8219 (2019)M. Falco, L. Castro, J.R. Nair, F. Bella, F. Bardé, G. Meligrana, C. Gerbaldi, ACS Appl. Energy Mater. 2, 1600-1607 (2019)M. Falco et al., Electrochem. Commun. 118 106807 (2020)S. Saffirio, M. Falco, G.B. Appetecchi, F. Smeacetto, C. Gerbaldi, Journal of the European Ceramic Society, 42(3), 1023-1032 (2022).

A nanocrystal garnet skeleton-derived high-performance composite solid-state electrolyte membrane

Composite solid-state electrolytes (SSEs) can improve the flexibility of the oxide SSEs to decrease the interfacial resistance between the electrolytes and the electrodes. However, the ceramic nanofillers within the composite SSEs suffer from the agglomeration at high concentrations, decreasing the ion conductivities. In this study, a continuous nanocrystal Li6.5La3Zr1.5Ta0.5O12 (LLZTO) skeleton is prepared by the ultrafast high-temperature sintering (UHS) together with tape-casting. Due to the short sintering time of ∼5 s from precursors, the LLZTO grains are restrained to ∼300 nm with limited Li loss. Even with trace solvent (3 wt%), the composite SSE membrane exhibits an ion conductivity of 5 × 10−4 S⋅cm−1, ∼50 times higher than the DOL electrolyte (1 × 10−5 S⋅cm−1, 8 wt% solvent), which further proves the high Li-ion conductivity of the nanocrystal LLZTO skeleton. The composite SSE membrane exhibits a critical current density of 3.4 mA⋅cm−2, among the highest reported values for ceramic-polymer SSEs. The Li/composite SSEs/Li symmetric cells can cycle ∼ 120 h at the current density from 0.2 to 0.4 mA⋅cm−2. The LiFePO4/LLZTO-PEGDA composite SSEs/Li full cell exhibits a high specific discharge capacity of ∼150 mAh⋅g−1 for ∼50 cycles with a Coulombic efficiency of ∼97%. To explore the processability of the membrane with large size, we also demonstrate a pouch cell (2 cm × 5 cm) with a high specific capacity of ∼150 mAh⋅g−1 for ∼25 cycles and a capacity retention of ∼94.5%. This work paves a new way to manufacture the nanocrystal ceramic SSE skeleton for high energy density all-solid-state batteries.

High-performance lithium metal batteries enabled by a nano-sized garnet solid-state electrolyte modified separator

Lithium metal batteries, as one of high-energy-density batteries, have become the hot spot for numerous researchers. However, serious safety problems caused by lithium dendrites need to be urgently addressed. In this work, we introduce nano-sized garnet solid-state electrolyte Li6.75La3Zr1.75Ta0.25O12 (LLZTO) to fabricate a high-safety thin composite solid electrolyte membrane (20 μm) that is simple in process and facile in preparation conditions. The thin composite solid electrolyte film has better wrinkle resistance than ordinary polyethylene (PE) films and can guide the uniform deposition of lithium ions and suppress the growth of lithium dendrites. The thermal stability of the PE separator modified by double-coated nano-sized LLZTO is enhanced, which exhibits only 30 % shrinking percentage at 140 °C in comparison with 90 % of ordinary PE. The lithium symmetric cell with the nano-sized garnet solid-state electrolyte modified separator is relatively stable after 1000 h cycling at the current density of 1 mA cm−2. More importantly, after adding the adaptable electrolyte, the lithium metal battery assembled with modified separator can be maintained for 150 cycles (0.2C) stably with a high cathode active material loading of NCM811 (18 mg cm−2), and can maintain above 95 % Coulombic efficiency on average. Our work provides a pathway for the preparation of superior thermal stability and high safety garnet-based composite membranes towards lithium metal batteries.

Mechanically robust and conductive zwitter ionic polymer coated electrospun nanofibrous electrolyte membranes for wireless human motion detection and capacitor applications

To address the limitations of poor ionic conductivity, low toughness, and high mass ratios in hydrogel-based electrolytes for flexible energy storage and wearable devices, here in a simple synthesis method of poly(ionic liquids) (PILs) based electrolyte membrane was developed. Briefly, PILs were utilized to coat electrospun PVDF-HFP nanofibrous membranes, resulting in ionically conducting composite electrolyte membranes (CPEMs) with enhanced physio-chemical properties. The obtained CPEMs exhibited an ionic conductivity of 0.056 S/m, along with a high tensile strength of 5.06 MPa and elongation to break of 156 %. Furthermore, we utilized these CPEMs as the electrolyte in symmetric capacitors by sandwiching them between carbon nanotube (CNT) coated Ni-foams. The resulting capacitors demonstrated a specific capacitance of 170F/g, an energy density of 53.41 Wh/kg, and a power density of 108.9 W/kg at an applied current of 1 mA. The suitability of these CPEMs as chemo-resistive sensors was investigated by attaching them to different body parts and monitoring changes in resistance during physical motion. The results demonstrated that the CPEMs exhibited effective gauge factors ranging from 1.85 to 6.44 and could detect movements up to 1 % strains.

Stable ion transport enabled by self-supported membranes with direct interfacial driving effect for lithium metal batteries

Composite electrolyte membranes with 3D nanofiber network structure, which can adjust internal stress to achieve cyclic stability, has been proved to play an important role in the cycle process of lithium metal batteries. However, its application is greatly impeded by the inherent instability interface. Here, we have created an excellent ion transport system through simple interface engineering design. The system weakens the interaction between PEO and Li+ via a direct interfacial driving mechanism that establishes the ion bonds (Li-O/Zn-O) between LLZO/ZnO and PEO respectively, thereby achieving stable ion transport. As a result, Li | LPZ-5 CSE | Li battery displays highly stable Li plating/stripping cycling for over 1000 h at 0.1 mA cm−2. In addition, lithium metal batteries (LMBs) based on LiFePO4 cathode can stably cycle for 250 cycles with a specific capacity of 151.9 mAh g−1 (50 °C, 0.2 C). This work provides a straightforward and effective strategy that employs the stable ion transfer process at molecular-level to construct a self-supported membrane, which is positive to the development of long-cycle-life LMBs.

Facilitating Li+ conduction channels and suppressing lithium dendrites by introducing Zn-based MOFs in composite electrolyte membrane with excellent thermal stability for solid-state lithium metal batteries

Facilitating Li+ conduction channels and suppressing lithium dendrites by introducing Zn-based MOFs in composite electrolyte membrane with excellent thermal stability for solid-state lithium metal batteries