Room Temperature Ionic Conductivity Research Articles

Nonstoichiometry Induced Amorphous Grain Boundary of Na5SmSi4O12 Solid-State Electrolyte for Long-Life Dendrite-Free Sodium Metal Battery.

Oxide ceramics are considered promising candidates as solid electrolytes (SEs) for sodium metal batteries. However, the high sintering temperature induced boundaries and pores between angular grains lead to high grain boundary resistance and pathways for dendrite growth. Herein, we report a grain boundary modification strategy, which in situ generates an amorphous matrix among Na5SmSi4O12 oxide grains via tuning the chemical composition. The mechanical properties as well as electron mitigating capability of modified SE have been significantly enhanced. As a result, the SE achieves a room-temperature total ionic conductivity of 5.61 mS cm-1, the highest value for sodium-based oxide SEs. The Na|SE|Na symmetric cell achieves a high critical current density of 2.5 mA cm-2 and excellent cycle life over more than 2800 h at 0.15 mA cm-2 without dendrite formation. The full cell with Na3V2(PO4)3 as the cathode demonstrates impressive cycling performance, maintaining stability over 3000 cycles at 5C without observable loss of capacity.

Hydrogen-bond-driven high ionic conductivity, Li+ transfer number, and lithium-interface stability of poly(vinylidene fluoride-hexafluoropropylene)-based solid-state electrolytes

Poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP)-based solid electrolytes with wide electrochemical windows and high thermal stabilities are promising candidates for use in solid-state lithium batteries. However, the practical applications of these electrolytes are currently hindered by their low room-temperature ionic conductivity, limited Li+ transfer number, and the poor stability of the lithium/electrolyte interface. This study proposes a ‘one stone, three birds’ modification method, wherein a small amount of lithium carboxymethylcellulose (CMC-Li) containing rich hydroxyl groups is added to form abundant hydrogen bonds with numerous electronegative C–F groups in the PVDF-HFP molecular chain and lithium bistrifluoromethane sulfonimide (LiTFSI). The strong connections formed between CMC-Li and PVDF-HFP or TFSI− significantly reduced the crystallinity of PVDF-HFP, promoted the dissociation of LiTFSI, and anchored TFSI−, achieving a synchronous improvement in the ionic conductivity and Li+ transfer number. The hydrogen bonds drove the densification of the membrane surface, improving the lithium/electrolyte compatibility at the interface. The ionic conductivity of the modified electrolytes was 5.1 × 10−4 S cm−1 and the Li + transfer number was 0.72 at room temperature. A Li||Li symmetric cell demonstrated stable cycling over 1000 h at 0.2 mA cm−2, where the initial discharge capacity of an all-solid-state cell was enhanced to 165.1 mAh g−1, with steady cycling for 400 runs. Thus, this study provides a novel and effective method for promoting the practical application of solid-state electrolytes.

Polyoxymethylene-based solid polymer electrolyte for high-performance room-temperature all-solid-state lithium batteries

Compared with flammable liquid electrolytes, solid state electrolytes show promising potential for lithium-ion batteries with high safety and high energy density simultaneously due to their high thermal stability, mechanical strength, excellent chemical and electrochemical stability. Solid polymer electrolytes are an attractive choice to achieve high energy density due to their thinness and good manufacturability. However, traditional solid polymer electrolytes typically need to operate at above 60 °C due to the insufficient room-temperature ionic conductivity, thereby limiting its practical application in common room temperature lithium-ion batteries. Here, we report a novel design of polyoxymethylene (POM)-based solid polymer electrolytes for high-performance room-temperature all-solid-state lithium batteries. This design includes POM and lithium bis(trifluoromethylsulfonyl)amine (LiTFSI), which offers the similar structure to polyethylene oxide based solid electrolyte while with shorter chain segments to achieve higher ionic conductivity (2.8 × 10−4S cm−1) and mechanical strength at room temperature. As a result, lithium dendrites can be efficiently suppressed, and symmetrical Li-Li cells have demonstrated more than 300 h of cycling at 0.05 mA cm−2. The wide electrochemical stability window of 4.75 V also enables broader application for full cells. All-solid-state lithium batteries fabricated with POM/LiTFSI exhibit excellent cycling stability for 150 cycles at 0.2 C rate at room temperature. The design breaks through the useable temperature limit of solid polymeric electrolytes and broaden their application in all-solid-state lithium batteries.

In situ synthesis of cross-linking gel polymer electrolyte for lithium metal batteries

AbstractThe room temperature ionic conductivity of polyethylene oxide (PEO)-based polymer electrolytes is low, the electrochemical window is narrow, and the mechanical strength is relatively poor. In this work, a cross-linking gel-based solid composite polymer electrolyte (CG-SCPE) was synthesized by introducing electrochemically stable carbonate-based functional groups. The synthesized CG-SCPE presents excellent tensile strength (26 MPa) and a wide electrochemical stability window (> 4.5 V vs. Li/Li+). Meanwhile, the in situ polymerization method induced by thermal heating resulted in good compatibility between electrodes/electrolytes. In addition, the assembled LiNi0.5Co0.2Mn0.3O2/CG-SCPE/Li battery exhibited satisfactory electrochemical performance. Therefore, the gel polymer electrolyte CG-SCPE with cross-linking network provides the possibility for future application of safe and high-performance solid-state lithium metal batteries. The results indicate that the introduction of cross-linking framework can simultaneously improve the mechanical strength, thermal stability, and electrochemical performance of solid polymer electrolyte.

A highly flexible and adhesive polymer electrolyte with fast ion conduction prepared via UV-induced in-situ polymerization for lithium metal batteries

Cathode–electrolyte integration via in-situ polymerization is an effective strategy to reduce interfacial resistance in solid-state/quasi-solid-state lithium batteries; however, ion conduction in the fraction of polymer electrolyte is still to be enhanced. Herein, we demonstrate a separator-free cathode–electrolyte integrated structure employing a novel poly(di(ethylene glycol) ethyl ether acrylate)-based quasi-solid polymer electrolyte (LiTFSI-poly(DEGA)-FEC QSPE, denoted as PDEGA-QSPE), prepared via UV-assisted in-situ polymerization. Poly(DEGA) as a linear polymer contains abundant ethylene oxide (EO) segments in its branched chain, exhibiting excellent flexibility and high adhesion. Benefited from the flexible molecular structure, PDEGA-QSPE exhibits a glass transition temperature (Tg) as low as around −68 °C and a good room-temperature ionic conductivity of 2.3 × 10−4 S cm−1, and it also shows an oxidative potential up to 4.7 V. The LiFePO4|PDEGA-QSPE|Li battery possesses an initial capacity of 149.2 mAh g−1 and a capacity retention of 92.5 % after 300 cycles at 0.2C under room temperature, and poly(DEGA)-based QSPE also has the potential to be applied to the high-voltage NCM811||Li battery. Compared with widely-employed monomers for in-situ polymerization such as poly(ethylene glycol) diacrylate (PEGDA), poly(DEGA) possesses remarkably improved flexibility and ion conduction capability, exhibiting broad research and application prospects.

Solvation engineering of non-aqueous electrolytes for room-temperature fluoride-ion batteries

Fluoride-ion batteries (FIBs) with high energy density and low cost are a promising new generation battery system for renewable energy storage. However, their room-temperature operation is strongly impeded by the lack of compatible electrolytes. Herein, we demonstrate that a stable room-temperature FIB can be achieved by tailoring the solvation chemistry of a non-aqueous liquid electrolyte. As validated by computational modeling and spectroscopic investigations, the cost-efficient β-hydrogen-free tetramethylammonium fluoride (TMAF) salt can efficiently prevent Hofmann elimination-induced electrolyte decomposition. Meanwhile, the synergistic effect of strong-polarity solvent and anion acceptor additive endows the high salt solubility (up to 0.7 M) and room-temperature ionic conductivity (6.12×10−3 S cm−1 at 25 °C) for the electrolyte. Owing to the virtue of this new electrolyte design, the Zn||CuF2 and Li||CuF2 FIBs were successfully constructed, delivering high reversibility, stable interface, and extended life. This work offers a new pathway for clearing the formidable bottlenecks in developing high-performance Fluoride-ion batteries.

AgF-PEO composite interfacial layer for electrolyte-free LAGP-based lithium metal batteries

NASICON-type LAGP solid state electrolyte has become one of the most promising solid-state electrolytes due to its superior performance such as favorable room-temperature ionic conductivity, high stability in air, wide electrochemically stable window, and low cost. The key constraint to the development of LAGP electrolyte is the LAGP/Li interface problem. In this paper, a composite interfacial layer (AgF@Li-PEO@LAGP) is introduced between LAGP electrolyte and electrode material. The LiF and Ag nanoparticles are generated on the Li surface by utilizing the substitution reaction to uniform lithium flux and prevent the side reaction, while the flexible PEO polymer buffer layer on the LAGP will improve the interface wettability. The Li/LAGP/Li symmetric cell modified with composite interfacial layer can maintain a low polarization voltage of 0.11 V at 0.1 mA cm−2 for stable cycling for more than 1200 h. The full cell also shows excellent cycling stability with the capacity retention of 93.6 % after 100 cycles. The composite interface layer can realize the elimination of liquid electrolyte and greatly reduce interface resistance. This broadens the road for the realization of all-solid-state batteries.

Neuron‐Like Silicone Nanofilaments@Montmorillonite Nanofillers of PEO‐Based Solid‐State Electrolytes for Lithium Metal Batteries with Wide Operation Temperature

AbstractPoly(ethylene oxide) (PEO)‐based composite solid electrolytes (CSEs) are promising to accelerate commercialization of solid‐state lithium metal batteries (SSLMBs). Nonetheless, this is hindered by the CSEs’ limited ion conductivity at room temperature. Here, we propose design, synthesis, and application of the bioinspired neuron‐like nanofillers for PEO‐based CSEs. The neuron‐like superhydrophobic nanofillers are synthesized by controllably grafting silicone nanofilaments onto montmorillonite nanosheets. Compared to various reported fillers, the nanofillers can greatly improve ionic conductivity (4.9×10−4 S cm−1, 30 °C), Li+ transference number (0.63), oxidation stability (5.3 V) and mechanical properties of the PEO‐based CSEs because of the following facts. The distinctive neuron‐like structure and the resulting synaptic‐like connections establish numerous long‐distance continuous channels over various directions in the PEO‐based CSEs for fast and uniform Li+ transport. Consequently, the assembled SSLMBs with the CSEs and LiFePO4 or NCM811 cathodes display superior cycling stability over a wide temperature range of 50 °C to 0 °C. Surprisingly, the pouch batteries with the large‐scale prepared CSEs kept working after being repeatedly bent, folded, cut or even punched in air. We believe that design of neuron‐like nanofillers is a viable approach to produce CSEs with high room temperature ionic conductivity for SSLMBs.

Neuron-Like Silicone Nanofilaments@Montmorillonite Nanofillers of PEO-Based Solid-State Electrolytes for Lithium Metal Batteries with Wide Operation Temperature.

Poly(ethylene oxide) (PEO)-based composite solid electrolytes (CSEs) are promising to accelerate commercialization of solid-state lithium metal batteries (SSLMBs). Nonetheless, this is hindered by the CSEs' limited ion conductivity at room temperature. Here, we propose design, synthesis, and application of the bioinspired neuron-like nanofillers for PEO-based CSEs. The neuron-like superhydrophobic nanofillers are synthesized by controllably grafting silicone nanofilaments onto montmorillonite nanosheets. Compared to various reported fillers, the nanofillers can greatly improve ionic conductivity (4.9×10-4 S cm-1, 30 °C), Li+ transference number (0.63), oxidation stability (5.3 V) and mechanical properties of the PEO-based CSEs because of the following facts. The distinctive neuron-like structure and the resulting synaptic-like connections establish numerous long-distance continuous channels over various directions in the PEO-based CSEs for fast and uniform Li+ transport. Consequently, the assembled SSLMBs with the CSEs and LiFePO4 or NCM811 cathodes display superior cycling stability over a wide temperature range of 50 °C to 0 °C. Surprisingly, the pouch batteries with the large-scale prepared CSEs kept working after being repeatedly bent, folded, cut or even punched in air. We believe that design of neuron-like nanofillers is a viable approach to produce CSEs with high room temperature ionic conductivity for SSLMBs.

Understanding Na+ Diffusion, Physicochemical Behavior, and Electrochemical Performance of a Gel Polymer Electrolyte.

Gel polymer electrolytes (GPEs) represent a credible alternative to organic liquid electrolytes (LEs) for safer sodium metal batteries. As a compromise between solid polymer electrolytes and LEs, GPEs ensure a good ionic conductivity, improve the electrolyte/electrode interface, and prevent solvent leaks. Herein, a GPE based on acrylate-bifunctionalized polyethylene glycol chains mixed with an ether solvent (TEGDME) and a polyethylene glycol diacrylate (PEG600DA) in a 50/50 wt % ratio was prepared by ultraviolet photopolymerization. Sodium bis(fluorosulfonyl)imide salt (NaFSI) was added at different concentrations to study its interactions with the solvent and/or the cross-linked polymer. Infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and swelling ratio characterizations were combined to determine the physicochemical properties of the GPE. Complementary characterizations including electrochemical impedance spectroscopy, chronopotentiometry, and cyclic voltammetry allowed correlating the physicochemical properties of the GPE to its electrochemical performance. Then, improvements were obtained by careful combination of its components. The cross-linking agent allowed us to obtain a polymer matrix that traps the organic solvent and prevents leakage. Such a solvent inclusion reduces the rigidity of the membrane and lowers its viscosity, offering a room temperature ionic conductivity of 4.8 × 10-4 Ω-1 cm-1. The control of polymer's tortuosity leads to a stable cycling vs sodium metal over several hundred hours without increase of the polarization. Finally, optimization of the salt loading plays a major role in electrostatic cross-linking, leading to an improvement of the mechanical properties of the GPE without reducing its conductivity.

Self‐Extinguishing and Low‐Cost Quasi‐Solid Polymer Electrolyte for Room Temperature Lithium Metal Batteries

Most modification strategies of polyethylene oxide (PEO)‐based solid polymer electrolyte focus on improving the room temperature ionic conductivity, while disregarding its inherent flammability that poses substantial safety hazard. Herein, a self‐extinguishing quasi‐solid‐state polymer electrolyte (PTTF‐SPE), which combines excellent room temperature electrochemical properties and high safety, has been developed by introducing triethyl phosphate (TEP) as a low‐cost and highly effective flame retardant. The cross‐linking structure derived from ‐CH2‐CH2‐O‐ segments of tetramethylene glycol dimethyl ether (TEGDME) and PEO makes a contribution to a high amorphous state of polymer. A robust solid electrolyte interphase (SEI) formed by preferential decomposition of fluoroethylene carbonate (FEC) that acts as a film‐forming additive, which can prevent TEP from degradation at lithium metal anode. The optimized PTTF‐SPE exhibits high ionic conductivity (0.54×10‐3 S/cm) and lithium transference number (0.71) at room temperature. The LiFePO4||Li battery demonstrates excellent cycle life over 500 cycles at 0.5 C with a high average discharge capacity of 131 mAh/g. A symmetric Li||Li battery that operating for 850 hours indicates a good compatibility of PTTF‐SPE towards lithium metal. This work provides a new idea for developing high‐energy‐density and high‐safety lithium‐metal batteries (LMBs) for room temperature.

Ionic Liquid Crystal-Polymer Composite Electromechanical Actuators: Design of Two-Dimensional Molecular Assemblies for Efficient Ion Transport and Effect of Electrodes on Actuator Performance.

We present the development of free-standing ionic liquid crystal-polymer composite electrolyte films aimed at achieving high-frequency response electromechanical actuators. Our approach entails designing novel layered ionic liquid-crystalline (LC) assemblies by complexing a mesomorphic dimethylphosphate with either a lithium salt or a room-temperature ionic liquid through the formation of ion-dipole interactions or hydrogen bonds. These electrolytes, exhibiting room-temperature ionic conductivities on the order of 10-4 S cm-1 and wide LC temperature ranges up to 77 °C, were successfully integrated into porous polymer networks. We systematically investigated the impact of ions and electrodes on the performance of ionic electroactive actuators. Specifically, the Li+-based liquid crystal-polymer composite actuator with PEDOT:PSS electrodes demonstrated the highest bending deformation, achieving a strain of 0.68% and exhibiting a broad frequency response up to 110 Hz, with a peak-to-peak displacement of 3 μm. In contrast, the ionic-liquid-based liquid crystal-polymer composite actuator with active carbon electrodes showcased a bending response at a maximum frequency of 50 Hz and a force generation of 0.48 mN, without exhibiting the back relaxation phenomenon. These findings offer valuable insights for advancing high-performance electromechanical systems with applications ranging from soft robotics to haptic interfaces.

Reasonable design a high-entropy garnet-type solid electrolyte for all-solid-state lithium batteries

Traditional garnet solid electrolyte (Li7La3Zr2O12) suffers from low room temperature ionic conductivity, poor air stability, high sintering temperature and energy consumption. Considering the development prospects of high-entropy materials with high structural disorder and strong component controllability in the field of electrochemical energy storage, herein, a novel high-entropy garnet-type oxide solid electrolyte, Li5.75Ga0.25La3Zr0.5Ti0.5Sn0.5Nb0.5O12 (LGLZTSNO) was constructed by partially replacing the Li and Zr sites in Li7La3Zr2O12 with Ga and Ti/Sn/Nb elements, respectively. The experimental and density functional theory (DFT) calculation results show that the high-entropy LGLZTSNO electrolyte has preferable room temperature ion conductivity, air stability, interface contact performance with lithium anode, and the ability to suppress lithium dendrites. Thanks to the improvement of electrolyte performance, the critical current density of Li/Ag@LGLZTSNO/Li symmetric cell was increased from 0.42 to 1.57 mA cm−2, and the interface area specific impedance (IASR) was reduced from 765.2 to 42.3 Ω cm2. Meanwhile, the Li/Ag@LGLZTSNO/LFP full cell also exhibits excellent rate performance and cycling performance (148 mA h g−1 at 0.1 C and 124 mA h g−1 at 0.5 C, capacity retention up to 84.8% after 100 cycles at 0.1 C), showing the application prospects of high-entropy LGLZTSNO solid electrolyte in high-performance all solid state lithium batteries.

Constructing in-situ polymerized electrolyte for room-temperature solid-state chloride ion battery with enhanced electrochemical performance

Considering large volume variation and dissolution issues of some promising electrode materials for chloride ion batteries (CIB), the construction of solid polymer electrolytes (SPE) for efficient chloride ion transport is intriguing. However, this is hindered by low ionic conductivity of chloride SPEs and poor cycling performance of CIBs. Herein, an in-situ polymerized and cross-linked poly(ethylene glycol) diacrylate-based chloride SPE with a low plasticizer content of succinonitrile is designed, yielding a room-temperature ionic conductivity of 7.6 × 10−5 S cm−1, which is higher than that of previously reported SPEs for CIBs. Moreover, the use of the as-prepared SPE achieves an integrated organic cathode with significantly enhanced rate performance and capacity retention of 96.1 % after 100 cycles at room temperature, which is much higher than 49.9 % (80 cycles) of the cathode in the CIB with a sandwiched structure. These improved properties are also superior to that of other reported cathodes coupled with different chloride SPEs. The chloride ion transfer mechanism of the cathode is revealed by X-ray photoelectron spectroscopy and energy dispersive spectroscopy.

Customized electrospun multilayer composite polymer electrolytes: PEO-PAN-NbO2 nanofiber membrane for enhancing the performance of lithium-ion batteries

Ground-breaking research into the development of a multilayer composite polymer electrolyte aims to enhance the safety associated with liquid electrolytes utilized in lithium batteries. The electrolyte consists of two outer layers made of electrospun poly(vinylidene fluoride) (PVDF) and a middle layer comprised of a fibrous membrane containing PEO, PAN-PEO, PEO-NbO2, and PAN-PEO-NbO2. The investigated PEO-PAN-NbO2 system demonstrates a higher room temperature ionic conductivity of 2.451 × 10−1 mS cm−1 than that of single-phase electrolyte systems. Incorporating inorganic fillers such as NbO2 into PEO polymer electrolytes, in conjunction with PAN copolymerization, significantly enhances ionic conductivity and amplifies surface area. Consequently, the utilization of these techniques that demonstrate increased polymer membranes leads to improved efficiency and security of solid-state electrochemical devices. The multilayer composite polymer electrolyte is created by continuous electrospinning, which allows for precise control and improves safety features.

A Water-in-Salt Electrolyte for Room-Temperature Fluoride-Ion Batteries Based on a Hydrophobic-Hydrophilic Salt.

Realizing room-temperature, efficient, and reversible fluoride-ion redox is critical to commercializing the fluoride-ion battery, a promising post-lithium-ion battery technology. However, this is challenging due to the absence of usable electrolytes, which usually suffer from insufficient ionic conductivity and poor (electro)chemical stability. Herein we report a water-in-salt (WIS) electrolyte based on the tetramethylammonium fluoride salt, an organic salt consisting of hydrophobic cations and hydrophilic anions. The new WIS electrolyte exhibits an electrochemical stability window of 2.47 V (2.08-4.55 V vs Li+/Li) with a room-temperature ionic conductivity of 30.6 mS/cm and a fluoride-ion transference number of 0.479, enabling reversible (de)fluoridation redox of lead and copper fluoride electrodes. The relationship between the salt property, the solvation structure, and the ionic transport behavior is jointly revealed by computational simulations and spectroscopic analysis.

Defect chemistry engineering of Ga-doped garnet electrolyte with high stability for solid-state lithium metal batteries

Abstract Ga-doped Li7La3Zr2O12 (Ga-LLZO) has long been considered as a promising garnet-type electrolyte candidate for all-solid-state lithium metal batteries (ASSLBs) due to its high room temperature ionic conductivity. However, the typical synthesis of Ga-LLZO is usually accompanied by the formation of undesired LiGaO2 impurity phase that causes severe instability issue of electrolyte in contact with molten Li metal during half/full cells assembly. In this study, we show that by simply engineering the defect chemistry of Ga-LLZO, namely, the lithium deficiency level, LiGaO2 impurity phase is effectively inhibited in the final synthetic product. Consequently, defect chemistry engineered Ga-LLZO exhibits excellent electrochemical stability against lithium metal, while its high room temperature ionic conductivity (~1.9 × 10-3 S·cm-1) is well reserved. The assembled Li/Ga-LLZO/Li symmetric cell has a superior critical current density of 0.9 mA·cm-2, and cycles stably for 500 hours at a current density of 0.3 mA·cm-2. This research facilitates the potential commercial applications of high performance Ga-LLZO solid electrolyte in ASSLBs.

Nonflammable in situ PDOL‐based gel polymer electrolyte for high‐energy‐density and high safety lithium metal batteries

AbstractDue to its high energy density and low interface impedance, in situ polymerized gel electrolytes were considered as a promising electrolyte candidate for lithium metal batteries (LMBs). In this work, a new flame‐retardant gel electrolyte was prepared via in situ ring‐opening polymerization of DOL and TEP. The PDOL–TEP electrolyte exhibits excellent room temperature ionic conductivity (0.38 mS cm−1), wide electrochemical window (4.4 V), high Li+ transference number (0.57), and enhanced safety. Thus, the NCM811||Li cells with PDOL–TEP electrolyte exhibit excellent cycle stability (82.7% of capacity retention rate after 300 cycles at 0.5 C) and rate performance (156 and 119 mAh g−1 at 0.5 and 1 C). Furthermore, phosphorus radicals decomposed from TEP can combine with hydrogen radicals to block the combustion reaction. This work provides an effective method for the preparation of solid‐state LMBs with high voltage, high energy density, and high safety.

In situ polymerization design of a quasi-solid electrolyte enhanced by NMP additive for lithium metal batteries

Solid polymer electrolytes (SPEs) are considered one promising candidate for lithium metal batteries due to their high flexibility, low cost, and roll-to-roll scalability. However, conventional SPEs prepared via ex situ methods are confronted with challenges such as poor contact and high resistance at the electrode|SPE interface, as well as low ionic conductivity at room temperature. In this study, we developed a quasi-solid electrolyte (QSE) using an in situ polymerization approach, employing butyl acrylate as the monomer and incorporating NMP as an additive. Spectroscopic investigations and DFT calculations revealed that NMP tends to form an overleaf-structured [Li(NMP)3][TFSI] complex with LiTFSI, promoting lithium salt dissociation. Owing to this advantage, the QSE exhibits high room-temperature ionic conductivity (6.94 × 10−4 S cm−1) and an extensive electrochemical stability window (5.01 V vs. Li+/Li). Furthermore, the in situ polymerization method facilitates full contact at the interface, enhancing the interfacial stability and reducing the interface resistance, thus resulting in stable cycling of Li|Built-in QSE|Li symmetric cell for 1100 h at 0.1 mA cm−2. The assembled LiFePO4|Built-in QSE|Li cell also demonstrates excellent rate and long-term cycling performance. Our findings offer valuable insights into the interaction between organic additives and lithium salts and present a novel strategy for the development of polymer electrolytes.

Comprehensive Dopant Screening in Li7La3Zr2O12 Garnet Solid Electrolyte

AbstractPromising Li7La3Zr2O12 (LLZO) garnet electrolytes for solid Li batteries are highly sensitive to doping to modify performance. Herein, LLZO samples with 59 different elemental dopants are synthesized with substitutions on each of the 3 sites (177 total materials). Many potential dopants successfully integrate into the LLZO garnet crystal structure (either cubic or tetragonal), while doping on the optimum site predicted from either previous DFT calculations or the far cheaper bond valence calculations promotes the cubic phase. Room temperature ionic conductivities of up to 1.2 × 10−3 S cm−1 are achieved demonstrating the quality of materials made in high‐throughput here, and 36 different dopants yield a >10x improvement in conductivity over undoped LLZO. This opens up dramatically the playground for new garnet materials. Other important metrics for electrolytes are also screened systematically. Electronic conductivity is generally suppressed with doping, though certain dopants need to be avoided as they enhance the risk of dendrite formation. The electrochemical stability window of the doped LLZO samples is also screened carefully and shows tunability with certain dopants improving the high voltage stability while others help at low voltage. The results will therefore serve to guide rational codoping studies to combine the benefits of various dopants.