High-performance Solid Polymer Electrolytes Research Articles

Novel PEO-based composite solid electrolytes for All-Solid-State Li-S battery

Solid polymer electrolytes (SPEs) were investigated for several decades due to their good compatibility with electrodes. However, meeting the essential requirements for solid polymer electrolytes, including enhanced ionic conductivity, superior solubility with conductive lithium salts, and robust interface stability when in contact with a Li anode, remains a formidable challenge. In our work, we found that transition metal carbides (NiNbCeC) over mesoporous silica (SBA-15) can be filled into the Polyethylene Oxide (PEO) matrix to form composite solid electrolytes which can greatly improve the ionic conductivity of PEO. We investigate a series of transition metal carbides with varying mass ratios of Cerium (5%, 10%, and 20%) to fabricate All-Solid-State Li-S batteries (ASSLi-S). Our results demonstrate that different mass ratios of Cerium play a pivotal role in enhancing the ionic conductivity of the composite solid electrolytes, reducing impedance levels from 9150 O (20% Ce) to 4000 O (5% Ce) to 1730 O (10% Ce). At room temperature, the high initial specific capacity at 1C and reversible specific capacity after 100 cycles are 525 and 363 mAh/g, 605 and 403 mAh/g, 246.3 mAh/g and 63.28 mAh/g for 5% Ce, 10%, and 20%, respectively. Furthermore, long-term cycling tests of ASSLi-S cells at 0.5C reveal promising performance, with the cell containing 10% Ce solid electrolytes delivering an initial specific capacity of 1165.7 mAh/g and maintaining 335 mAh/g after 200 cycles. This represents a significant breakthrough, demonstrating that PEO-based solid electrolytes can achieve impressive electrochemical results at room temperature. SEM characterization was employed to assess the volume change in the solid electrolyte layer and elemental distribution of solid electrolyte materials through cross-sectional analysis. This analysis revealed that the failure modes of solid-state Li-S cells can also be attributed to the migration of sulfur elements from the cathode to the solid electrolyte layer during the cycling process. XRD was utilized to study the crystallinity of composite solid electrolytes. This study represents a significant stride in the progress of high-performance solid polymer electrolytes for All-Solid-State Li-S batteries, shedding light on the failure modes of such batteries. It underscores the potential of composites based on transition metal carbides in addressing crucial challenges for their practical implementation in Solid-State Lithium-Sulfur Batteries.

Using Pegylated Graphene Oxide to Achieve High Performance Solid Polymer Electrolyte Based on Poly(ethylene oxide)/Polyvinyl Alcohol Blend (PEO/PVA).

Solid polymer electrolytes (SPEs) have emerged as a promising avenue for developing flexible lithium-ion batteries. However, the low ionic conductivity of polymers remains a primary challenge that has been the subject of intensive research efforts in recent years. In this work, polyethylene oxide (PEO), polyvinyl alcohol, lithium perchlorate (LiClO4), and graphene functionalized with polyethylene glycol (FGO) have been used to prepare SPE/FGO electrolytes by casting solution technique. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) confirmed the reduction of SPE crystals and the increase of amorphous phases. The results demonstrated that the presence of functionalized graphene had an effective role in reducing crystallinity. Furthermore, the thermal and mechanical stability of the samples were corroborated through thermogravimetric analysis (TGA) and tensile tests, respectively. Notably, the samples exhibited adequate ionic conductivity at room temperature, with the highest ionic conductivity of 5.2 × 10-5 S·cm-1 observed for 2%wt of FGO in SPE (SPE/FGO(2)).

Engineering 3D Interpenetrated ZIF-8 Network in Poly(ethylene oxide) Composite Electrolyte for Fast Lithium-Ion Conduction and Effective Lithium-Dendrite Inhibition

A novel 3D ZIF-8 network-reinforced polyethylene oxide (PEO) composite polymer electrolyte (Z-C-PAN-PEO) is successfully built, in which the network with an interpenetrated structure is tactfully developed by in situ assembling ZIF-8 nanoparticles on electrospinning carboxylated polyacrylonitrile (C-PAN) nanofiber surfaces. ZIF-8 with high porosity and unsaturated open metal sites will act as the bridge between C-PAN nanofibers and the PEO matrix. It is proven that the selected ZIF-8 can play a significant role in facilitating Li+ conduction and transference by effectively interacting with the oxygen atoms of C–O–C to promote the segmental movement of PEO and immobilizing TFSI– anions to release more free Li+. The 3D interpenetrating structure of Z-C-PAN further enables the conduction channels more consecutive and long-ranged, endowing the Z-C-PAN-PEO electrolyte with an optimum ionic conductivity of 4.39 × 10–4 S cm–1 and a boosted Li+ transference number of 0.42 at 60 °C. Other improvements occurring in the reinforced electrolytes are the broaden electrochemical stability window of ∼4.9 V and sufficient mechanical strength. Consequently, the stable Li-plating/stripping for 1000 cycles at 0.1 mA cm–1 witnesses the splendid compatibility against Li dendrite. The cycling performance of LiFePO4/Z-C-PAN-PEO/Li cells with a reversible capacity of 116.2 mAh g–1 after 600 cycles at 0.2 C guarantees the long-term running potential in lithium metal batteries. This study puts forward new insights in designing and exploiting the active role of MOFs for high-performance solid polymer electrolytes.

Oxygen Vacancy-Rich Ultrathin Co3O4 Nanosheets as Nanofillers in Solid-Polymer Electrolyte for High-Performance Lithium Metal Batteries

The development of high-performance solid-polymer electrolytes (SPEs) is a key to the practical application of lithium metal batteries (LMBs). The use of two-dimensional (2D) inorganic nanofiller is an efficient way to build poly(ethylene oxide) (PEO)-based SPEs with high ionic conductivity and stability. Herein, a series of 2D oxygen vacancy-rich Co3O4-y−x (x = 1, 2 and 3) with well-defined 2D nanostructures, a high surface area and controllable oxygen vacancy contents (Co3O4-y) was synthesized via a facile self-assembly method and NaBH4 reduction. When the 2D Co3O4-y−x (x = 1, 2 and 3) nanosheets are introduced as nanofillers in PEO-based SPEs, they can interact with the PEO to form a three-dimensional (3D) PEO/Co3O4-y film with uniform Li+ distribution and vertical diffusion channels, as well as strong adsorption of NO3− from LiNO3 electrolyte salt at the defective sites. As a result, the PEO/Co3O4-y−2 film reached a high ionic conductivity of 4.9 × 10−5 S cm−1, high Li+ a transference number of 0.51 and a wide electrochemical window over 4.6 V at 80 °C. The PEO/Co3O4-y−2 film enables the Li||PEO/Co3O4-y−2||LiFePO4 cell to deliver a high reversible capacity of 117.7 mAh g−1 at 2 C and to maintain 126.7 mAh g−1 at 1 C after 250 cycles with an initial capacity retention of 87.9%.

Decoupling Ion Transport and Matrix Dynamics to Make High Performance Solid Polymer Electrolytes.

Transport of ions through solid polymeric electrolytes (SPEs) involves a complicated interplay of ion solvation, ion-ion interactions, ion-polymer interactions, and free volume. Nonetheless, prevailing viewpoints on the subject promote a significantly simplified picture, likening ion transport in a polymer to that in an unstructured fluid at low solute concentrations. Although this idealized liquid transport model has been successful in guiding the design of homogeneous electrolytes, structured electrolytes provide a promising alternate route to achieve high ionic conductivity and selectivity. In this perspective, we begin by describing the physical origins of the idealized liquid transport mechanism and then proceed to examine known cases of decoupling between the matrix dynamics and ionic transport in SPEs. Specifically we discuss conditions for "decoupled" mobility that include a highly polar electrolyte environment, a percolated path of free volume elements (either through structured or unstructured channels), high ion concentrations, and labile ion-electrolyte interactions. Finally, we proceed to reflect on the potential of these mechanisms to promote multivalent ion conductivity and the need for research into the interfacial properties of solid polymer electrolytes as well as their performance at elevated potentials.

Electrochemical Modified Solid Electrolyte with a Li–Al–O Interface Layer for Improved Room-Temperature Rate Performance of Solid-State Lithium Batteries

Solid polymer electrolytes have good flexibility and are considered as a candidate material for high-energy density solid-state lithium batteries (SSLBs), which can effectively increase the capacity density. However, the lifetime and safety issues of the SSLBs caused by the growth of lithium dendrites hinder their practical applications. Herein, we demonstrate a simple in situ electrochemical method to form a Li–Al–O fast lithium-ion conductive layer between the lithium anode and the solid electrolyte interface. This method is also used to effectively inhibit the growth of lithium dendrites and achieve the long cycle life of SSLBs. The results show that at 0.25 mA·cm–2, the lithium symmetrical cell can be cycled stably for 1600 h, achieving uniform lithium plating and stripping. The Li/LiFePO4 cell exhibits a capacity retention rate of 85.6% after 300 cycles. This novel method of electrochemical interface modification constructs a high-performance solid polymer electrolyte with higher safety and longer cycle life.

A strong Lewis acid imparts high ionic conductivity and interfacial stability to polymer composite electrolytes towards all-solid-state Li-metal batteries

The development of high-performance solid polymer electrolytes is crucial for producing all-solid-state lithium metal batteries with high safety and high energy density. However, the low ionic conductivity of solid polymer electrolytes and their unstable electrolyte/electrode interfaces have hindered their widespread utilization. To address these critical challenges, a strong Lewis acid (aluminum fluoride (AlF3)) with dual functionality is introduced into polyethylene oxide) (PEO)-based polymer electrolyte. The AlF3 facilitates the dissociation of lithium salt, increasing the iontransfer efficiency due to the Lewis acid-base interaction; further the in-situ formation of lithium fluoride-rich interfacial layer is promoted, which suppresses the uneven lithium deposition and continuous undesired reactions between the Li metal and PEO matrix. Benefiting from our rational design, the symmetric Li/Li battery with the modified electrolyte exhibits much longer cycling stability (over 3600 h) than that of the pure PEO/lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) electrolyte (550 h). Furthermore, the all-solid-state LiFePO4 full cell with the composite electrolyte displays a much higher Coulombic efficiency (98.4% after 150 cycles) than that of the electrolyte without the AlF3 additive (63.3% after 150 cycles) at a large voltage window of 2.4–4.2 V, demonstrating the improved interface and cycling stability of solid polymer lithium metal batteries.

Tough Polymer Electrolyte with an Intrinsically Stabilized Interface with Li Metal for All-Solid-State Lithium-Ion Batteries

A high-performance solid polymer electrolyte (SPE) membrane that simultaneously addresses the issues of enhanced toughness and Li-dendrite mitigation for all-solid-state Li-ion batteries (ASSLIBs) is demonstrated. The membrane has a sandwiched structure consisting of a center poly(ethylene oxide)/lithium bis(trifluoromethanesulfonyl) imide (PEO/LiTFSI) electrolyte matrix laminated on both sides with electrospun high-polarity β-phase poly(vinylidene fluoride-co-hexafluoropropylene) (β-PVDF-HFP) nanofibers. The nanofiber layers impart remarkable enhancement in both mechanical and electrochemical properties of the SPE, including a 20-fold increase in tensile strength and a 48-fold increase in toughness, along with up to 4-fold enhancement in Li-ionic conductivity. Moreover, the highly polar fluorinated nanofiber cladding layers enable a stable Li-plating/stripping interface on the Li anode to efficiently mitigate dendrite formation, while improving the electrochemical interfacial stability with the cathode. In a Li|SPE|Li symmetric cell, the use of the sandwiched SPE is demonstrated to improve the cycle stability from short-circuiting at 144 h for a pristine PEO/LiTFSI membrane to no short-circuiting even up to 3600 h (1800 Li-plating-stripping cycles). In an example of LiFePO4|SPE|Li ASSLIBs, using the sandwiched membrane enables substantial reduction irreversible capacity upon charging to the high-voltage end and more than 80% capacity retention for over 1600 h. This work presents a feasible and facile design for an SPE for high-performance ASSLIBs.

Synergistic Effects of Plasticizer and 3D Framework toward High-Performance Solid Polymer Electrolyte for Room-Temperature Solid-State Lithium Batteries

Solid polymer electrolytes (SPEs) can alleviate the safety issues existing in commercialized lithium ion batteries with liquid electrolyte. However, the low room-temperature ionic conductivity and ...

Functional polyethylene glycol-based solid electrolytes with enhanced interfacial compatibility for room-temperature lithium metal batteries

A high-performance solid polymer electrolyte with enhanced interfacial compatibility was synthesized via an in situ polymerization of functional polyethylene glycol combined with the in situ formation of stable SEI layers by vinylene carbonate.

Controllable magnetic field aligned sepiolite nanowires for high ionic conductivity and high safety PEO solid polymer electrolytes

Poly (ethylene oxide) (PEO) polymer electrolyte, attracts great attention owing to its excellent flexibility, good processability and high safety compared with liquid electrolytes. However, its low ionic conductivity and weak ability to suppress the lithium dendrite severely restrict the further progress of PEO. Herein, we prepare a high ionic conductivity solid polymer electrolyte for all-solid-state lithium batteries by mixing PEO and magnetically aligned functionalized sepiolite (KFSEP) nanowires. The ionic conductivity of PEO/LiTFSI/10%⊥KFSEP solid polymer electrolyte is 2.0 × 10−5 S cm−1 at 20 °C (The ionic conductivity of PEO/LiTFSI solid polymer electrolyte is 4.0 × 10−7 S cm−1 at 20 °C). The experiments and simulation analysis indicate that the aligned nanowires provide a fast-moving channel for lithium ions. The capacity of Li/PEO/LiTFSI/10%⊥KFSEP/LFP cell is 130 mAh g−1 at 1.0 C under 60 °C after 450cycles. Furthermore, Li/PEO/LiTFSI/10%⊥KFSEP/LFP cell shows 150 mAh g−1 at 0.2 C under 25 °C. The Li/PEO/LiTFSI/10%⊥KFSEP/Li cell can work normally more than 600 h, indicating the high stability and lithium dendrite suppressing function of PEO/LiTFSI/10%⊥KFSEP. Overall, a high performance solid polymer electrolyte with higher safety is constructed by incorporating magnetically aligned sepiolite nanowires into PEO.

In-situ generation of high performance thiol-conjugated solid polymer electrolytes via reliable thiol-acrylate click chemistry

A kind of high performance thiol-conjugated solid polymer electrolytes is in situ generated via a facile thiol-acrylate Michael addition reaction between ethylene glycol dimethacrylate (EGDMA) and 3,6-dioxa-1,8-octane dithiol (DODT) without UV irradiation or thermal initiation. The resulting amorphous linear polymer P(EGDMA-DODT) has a high average molecular weight of 47,000 Da with a low glass transition temperature of −50 °C. The in-situ generated P(EGDMA-DODT) solid polymer electrolyte exhibits room temperature ionic conductivity up to 2.7 × 10 −5 S cm−1 with a high lithium ion transference number above 0.40 and electrochemical stability window up to 4.3 V vs. Li/Li+. Advantages of longer C–S bond length (1.81 Å), lower electronegativity (2.58) and moderate coordination facilitate the segment motion and contribute to higher room temperature ionic conductivity. It is demonstrated that the all-solid-state LiFePO4/Li cells using the in-situ generated P(EGDMA-DODT) electrolytes delivers considerable specific capacities, rate capability and excellent cyclic performance at room temperature. These results demonstrate that this thiol-acrylate click chemistry without UV irradiation or thermal initiation is a facile and intriguing strategy for in-situ preparing high performance solid polymer electrolytes.

Advanced Nanoclay-Based Nanocomposite Solid Polymer Electrolyte for Lithium Iron Phosphate Batteries.

High-performance solid polymer electrolytes (SPEs) have long been desired for the next generation of lithium batteries. One of the most promising ways to improve the morphological and electrochemical properties of SPEs is the addition of fillers with specific nanostructures. However, the production of such fillers is generally expensive and requires complicated preparation procedures. Halloysite nanotubes (HNTs), with their tubular structure, resemble carbon nanotubes in terms of geometric features and can be obtained at a relatively low cost. Previously, we reported that the HNT poly(ethylene oxide) composite SPE possesses excellent electrochemical and mechanical properties and outstanding cycling performance for all-solid-state lithium sulfur batteries. However, the HNT/SPE was not effective for lithium iron phosphate (LFP) batteries. The compatibility between the electrodes and the electrolyte sharply decreased, and no decent cycling performance was achieved. Therefore, a modification was studied which involves a minor addition of LFP during the preparation procedure. With this modification, good ionic conductivity (9.23 × 10-5 S cm-1 at 25 °C) is achieved, and compatibility between the electrodes and the electrolyte is enhanced. At the same time, an electrochemical stability window of 5.14 V and lithium-ion transference number of 0.46 are found. All-solid-state LFP batteries possessing excellent cycling performance are further demonstrated.

Highly conductive and mechanically robust nanocomposite polymer electrolytes for solid-state electrochemical thin-film devices

Abstract Ionic liquid-based polymer electrolyte composites (PECs) with high mechanical strength and ionic conductivity were fabricated by using a semicrystalline homopolymer network. Morphological, mechanical, and electrical properties of semicrystalline homopolymer-based PECs were investigated over the composition range of 10–50 polymer wt%. The PECs consisted of poly(vinylidene fluoride) (PVDF) and a room-temperature ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMI][TFSI]). The amorphous PVDF chains were solvated by the liquid electrolyte and interconnected the phase-separated PVDF crystalline-domains, acting as physical crosslinks. The ionic conductivity and specific capacitance of the homopolymer PECs were found to be very high, ranging from 0.4 to 4.9 mS/cm and from 2.6 to 9.1 μF/cm2, respectively. The elastic moduli of the PECs that range from 4 to 38 MPa were also greater than those of PECs prepared by using other polymeric networks. These PECs were successfully applied as electrolyte membranes in electrical double layer supercapacitors and as high-capacitance gate insulators in electrochemical thin-film transistors. These results provide detailed systematic data for fabricating high-performance solid polymer electrolytes for electrochemical thin-film devices.

A rational design of solid polymer electrolyte with high salt concentration for lithium battery

With the development of electrical energy storage and electrical vehicle, high safety is indispensable for lithium ion battery, therefore, high performance solid polymer electrolytes are the relentless pursuit of numerous researches. However, low ionic conductivity restricts the polymer electrolyte usage in commercialized lithium ion batteries. Among the candidates of polymer electrolytes, poly (ethylene carbonate) is promising due to its ability of high lithium salt dissociation. Nonetheless, these polymer electrolytes with high concentration salt always accompanies with an obvious deterioration of mechanical properties. Herein, via controlling the ratio of poly (ethylene carbonate) and poly (vinylidene fluoride-co-hexafluoropropene), a biphasic solid polymer electrolyte possessing high concentration lithium salt phase and good mechanical strength is prepared. Specifically, considering the role of polymer groups in lithium ion transport, it is speculated that dual-path of Li+ transport forms in the polymer electrolyte, which improves the conductivity remarkably. The prepared electrolyte realizes sufficient ionic conductivity (1.08 × 10−4 S/cm) at 30 °C, with a wide electrochemical window about 4.5 V (vs. Li+/Li), meanwhile exhibits the capacity of `suppression to lithium dendrite growth. Notably, with the polymer electrolyte, Li/LiFePO4 cell exhibits superior rate capacity and excellent cycling stability. This study proves new insights for polymer electrolyte design with high conductivity.

Recent Advancements in Polymer-Based Composite Electrolytes for Rechargeable Lithium Batteries

In recent years, lithium batteries using conventional organic liquid electrolytes have been found to possess a series of safety concerns. Because of this, solid polymer electrolytes, benefiting from shape versatility, flexibility, low-weight and low processing costs, are being investigated as promising candidates to replace currently available organic liquid electrolytes in lithium batteries. However, the inferior ion diffusion and poor mechanical performance of these promising solid polymer electrolytes remain a challenge. To resolve these challenges and improve overall comprehensive performance, polymers are being coordinated with other components, including liquid electrolytes, polymers and inorganic fillers, to form polymer-based composite electrolytes. In this review, recent advancements in polymer-based composite electrolytes including polymer/liquid hybrid electrolytes, polymer/polymer coordinating electrolytes and polymer/inorganic composite electrolytes are reviewed; exploring the benefits, synergistic mechanisms, design methods, and developments and outlooks for each individual composite strategy. This review will also provide discussions aimed toward presenting perspectives for the strategic design of polymer-based composite electrolytes as well as building a foundation for the future research and development of high-performance solid polymer electrolytes.

Manipulating Protein Configuration for High-Performance Solid Polymer Electrolytes

Solid polymer electrolytes (SPEs) are well known for their excellent mechanical properties and high safety. It will be significant to develop advanced SPEs for substituting currently used organic liquid electrolytes. However, determined by their ion-transport coupled with mobility of polymer segments, SPEs usually exhibit low ionic conductivity (10-8 ~ 10-6 S/cm) at room temperature, which severely limits their practical applications. Thus far, efforts on enhancing the ionic conductivity of SPEs have been primarily focusing on reducing crystallinity degree of the polymer hosts via introducing plasticizers, advanced nanofillers, other polymers, etc. while there have not existed effective ways to the control of the ion-transport pathways inside the SPEs. In our work, we discovered that by manipulating the configuration of denatured soy protein, the transportation of Li+ can be significantly promoted, which is of great interest for fabricating high-performance SPEs. Via carefully controlling critical factors, including denaturation of soy protein, loading level of lithium salt and temperature for the evaporation process of the electrolyte preparation, a protein-based solid electrolyte with high ionic conductivity (ca. 10-5 S/cm at room temperature) and modulus (ca. 1 GPa) was achieved, which has never been realized in any conventional SPEs. Meanwhile, the soy-protein-based SPE presents high lithium ion transference number of ca. 0.94. Molecular dynamic simulation results indicate that evaporation temperature for electrolyte preparation plays a critical role in controlling the configuration of protein. As a result, a more flexible protein configuration allows strong interactions between anions of lithium salts with the backbone oxygen and negative charge side groups of protein to form anion clusters that can facilitate the transportation of Li+. It is therefore speculated that this unique ion-transport mechanism is ceramic-like and is decoupled with mobility of protein chains. In addition, by introducing ceramic nanoparticles into denaturation of soy protein, the configuration of the protein was dramatically changed to result in a type of highly efficient nanofiller that enables fast ion-transport. A composite polymer electrolyte based on poly(ethylene oxide) (PEO) loaded with such hybrid nanofillers shows one order of magnitude improvement in ionic conductivity at room temperature, as compared with the one with untreated nanofillers. Moreover, the composite polymer electrolyte was demonstrated improved mechanical properties, and importantly improved adhesion properties that greatly benefit interfacial properties with the electrodes. The studies may open a new avenue for developing high-performance SPEs with promoted ion-transport by manipulating the configuration of the protein.

Poly(ethylene carbonate)-based electrolytes with high concentration Li salt for all-solid-state lithium batteries

High-performance solid polymer electrolyte (SPE) has long been desired for the next-generation high energy density and safe rechargeable lithium batteries. A SPE composed of 80 wt% lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 20% poly(ethylene carbonate) (PEC) and a polyamide (PA) fiber membrane backbone was prepared by solution-casting method. This solid electrolyte exhibits quite high ionic conductivity and lithium ion transference number (t+), and excellent mechanical strength. The as-prepared solid electrolyte shows good wettability to porous electrodes during cycles, which is beneficial to form ionically conductive phase throughout porous electrodes. All-solid-state LiFePO4|Li cells assembled with the as-prepared solid electrolyte deliver a high initial discharge specific capacity of 125.7 mAh·g−1 and good cycling stability at 55 °C (93.4% retention at 1C after 200 cycles), and superior cycle performance. Outstanding electrochemical performance can be mainly ascribed to the improved ionic conductivity in the entire porous electrodes due to the good wettability of SPE.

High-performance solid polymer electrolytes for lithium ion batteries based on sulfobetaine zwitterion and poly (ethylene oxide) modified polysiloxane

Herein we report a new high ionic conductivity and wide electrochemical window solid polymer electrolyte (SPE), which is developed via grafting sulfobetaine zwitterion (ZI) and poly (ethylene oxide) (PEO) chains on highly flexible polysiloxane backbone followed by crosslinking of tri(ethylene glycol) divinyl ether. The synergistic effect of zwitterion and PEO endows the SPE with an excellent ionic conductivity of 3.39 × 10−4 S cm−1 and the wide electrochemical stable window of 5.0 V (vs. Li/Li+) at room temperature. LiFePO4/Li half-cells with as-prepared solid polymer electrolyte present a high initial discharge capacity of 155 mAh g−1 and superior cycle stability with a capacity retention of 93% at 0.1 C after 100 cycles at 30 °C. In addition, LiNi0.5Mn1.5O4/Li half-cells employing such polymer electrolyte also deliver excellent cycle performance and stability. The above results indicate that the designed zwitterionic SPE appears to be a potential candidate for application in all-solid-state lithium-ion batteries.

Poly-4-vinylphenol (PVP) and Poly(melamine-co-formaldehyde) (PMF)-Based Atomic Switching Device and Its Application to Logic Gate Circuits with Low Operating Voltage.

In this study, we demonstrate a high-performance solid polymer electrolyte (SPE) atomic switching device with low SET/RESET voltages (0.25 and -0.5 V, respectively), high on/off-current ratio (105), excellent cyclic endurance (>103), and long retention time (>104 s), where poly-4-vinylphenol (PVP)/poly(melamine-co-formaldehyde) (PMF) is used as an SPE layer. To accomplish these excellent device performance parameters, we reduce the off-current level of the PVP/PMF atomic switching device by improving the electrical insulating property of the PVP/PMF electrolyte through adjustment of the number of cross-linked chains. We then apply a titanium buffer layer to the PVP/PMF switching device for further improvement of bipolar switching behavior and device stability. In addition, we first implement SPE atomic switch-based logic AND and OR circuits with low operating voltages below 2 V by integrating 5 × 5 arrays of PVP/PMF switching devices on the flexible substrate. In particular, this low operating voltage of our logic circuits was much lower than that (>5 V) of the circuits configured by polymer resistive random access memory. This research successfully presents the feasibility of PVP/PMF atomic switches for flexible integrated circuits for next-generation electronic applications.