High Conductivity Properties Research Articles

Photo-curable bio-based comb/bottle brush epoxy resin/beeswax/copper foam phase change materials with high enthalpy value, high conductivity, and multifunctional properties

At present, the demand for green energy has reached a new height in history, and thermal energy storage technology has been widely used to reduce energy consumption. It is still a challenge to develop bio-based polymeric form-stable phase change materials (FSPCMs) with high enthalpy value and thermal conductivity (TC), short curing time, and multifunctional properties. This work not only exploited a series of adjustable and photo-curable comb/bottle brush bio-based epoxy resin/beeswax (bw) FSPCMs with the above superiorities, but also revealed the effects of cross-linking density on the energy storage capacity and encapsulation rate of the FSPCMs. As a result, the optimal system can encapsulate the maximum amount of bw (60 wt%) and obtain the highest enthalpy value (142.1 J/g) with only 0.5% enthalpy loss. Through further introducing the optimal curing system into the copper (Cu) foam, the electromagnetic interference shielding property, TC, tensile strength, and photo-thermal conversion efficiency of the final composite (modified by Cu of 95% porosity) can reach 110 dB, 2.387 W m−1K−1, 2.81 MPa, and 80%, respectively, and the enthalpy value (84.2 J/g) is still satisfactory. This study can provide theoretical guidance for the structural design of reliable fast photo-curable bio-based polymeric FSPCMs with excellent phase change performances and multifunctional properties.

Designing of high performance MoS2@VZnS//AC hybrid battery supercapacitor device for the electrochemical energy storage and glucose detection

Due to their high conductive properties and superior specific capacitance, metal sulfides exhibit remarkable electrical conductivity. Transition metal dichalcogenides (TMDs) are regarded ideal options for energy harvesting devices due to their unique 2D arrangement and remarkable electrochemical properties. In this work, the typical exfoliation method (tip sonication method) was used to synthesize the molybdenum disulfide (MoS2). By using the hydrothermal method, the vanadium zinc sulfide is synthesized. The composite was analyzed through SEM, XRD, and XPS techniques to investigate its morphological, structural, and compositional characteristics comprehensively. The MoS2@VZnS electrode achieved a specific capacity (Qs) of 1025 Cg−1 at 3 mVs−1 after being tested in 1 M KOH. In a two-electrode set-up, activated carbon is used as a negative electrode, and MoS2@VZnS is used as a positive electrode for the fabrication of a hybrid supercapacitor. The asymmetric device has demonstrated a Qs of 285.4 Cg−1 at 1.4 Ag−1. The fabricated asymmetric supercapacitor device has manifested an excellent energy density (Ed) of 39.5 Whkg−1 and power density (Pd) of 2462.35 Wkg−1. Furthermore, in the durability test of MoS2@VZnS//AC, it exhibited an impressive capacity retention of 91.32% after enduring 5,000 cycles. Besides this, an investigation was conducted on a glucose electrochemical sensor utilizing MoS2@VZnS, to enhance its performance. The device showed extraordinary performance and considerable sensitivity against glucose, even up to a very high value. The multifunctional MoS2@VZnS nanocomposite electrode material provides new opportunities to design hybrid devices in energy storage devices and biomedical applications.

Self-healing and adhesive MXene-polypyrrole/silk fibroin/polyvinyl alcohol conductive hydrogels as wearable sensor

Conductive hydrogels become increasing attractive for flexible electronic devices and biosensors. However, challenges still remain in fabrication of flexible hydrogels with high electrical conductivity, self-healing capability and adhesion property. Herein, a conductive hydrogel (PSDM) was prepared by solution-gel method using MXene and dopamine modified polypyrrole as conductive enhanced materials, polyvinyl alcohol and silk fibroin as gel networks, and borax as cross-linking agent. Notably, the PSDM hydrogels not only showed high permeability (13.82 mg∙cm−2∙h−1), excellent stretch ability (1235 %), high electrical conductivity (11.3 S/m) and long-term stability, but also exhibited high adhesion performance and self-healing properties. PSDM hydrogels displayed outstanding sensing performance and durability for monitoring human activities including writing, finger bending and wrist bending. The PSDM hydrogel was made into wearable flexible electrodes and realized accurate, sensitive and reliable detection of human electromyographic and electrocardiographic signals. The sensor was also applied in human-computer interaction by collecting electromyography signals of different gestures for machine learning and gesture recognition. According to 480 groups of data collected, the recognition accuracy of gestures by the electrodes was close to 100 %, indicating that the PSDM hydrogel electrodes possessed excellent sensing performance for high precision data acquisition and human-computer interaction interface.

Synthesis of Superelastic, Highly Conductive Graphene Aerogel/Liquid Metal Foam and its Piezoresistive Application.

Graphene aerogel (GA) has important application potential as piezoresistive sensors due to its low density, high conductivity, high porosity, and good mechanical properties. However, the fabrication of GA-based sensors with good mechanical properties and excellent sensing performance is still challenging. Herein, liquid- metal-modified GAs (GA/LM) are proposed for the development of an excellent GA-based sensor. GA/LM with three-dimensional interconnected layered structure exhibits excellent compressive stress of 41 KPa and fast response time (<20 ms). While generally flexible GA composites cannot be compressed beyond 80 % strain without plastic deformation, GA/LM demonstrates a high compressive strength of 60 kPa under a strain of 90 %. A real-time pressure sensor was fabricated based on GA/LM-2 to monitor swallowing, pulse beating, finger, wrist and knee bending, and even plantar pressure during walking. These excellent features enable potential applications in health detection.

Inkjet‐printed flexible MXetronics: Present status and future prospects

AbstractOver the past several years, atomically thin two‐dimensional carbides, nitrides, and carbonitrides, otherwise known as MXenes, have been expanded into over fifty material candidates that are experimentally produced, and over one hundred fifty more candidates that have been theoretically predicted. They have demonstrated transformative properties such as metallic‐type electrical conductivities, optical properties such as plasmonics and optical nonlinearity, and key surface properties such as hydrophilicity, and unique surface chemistry. In terms of their applications, they are poised to transform technological areas such as energy storage, electromagnetic shielding, electronics, photonics, optoelectronics, sensing, and bioelectronics. One of the most promising aspects of MXene's future application in all the above areas of interest, we believe, is reliably developing their flexible and bendable electronics and optoelectronics by printing methods (henceforth, termed as printed flexible MXetronics). Designing and manipulating MXene conductive inks according to the application requirements will therefore be a transformative goal for future printed flexible MXetronics. MXene's combined property of high electrical conductivity and water‐friendly nature to easily disperse its micro/nano‐flakes in an aqueous medium without any binder paves the way for designing additive‐free highly conductive MXene ink. However, the chemical and/or structural and hence functional stability of water based MXene inks over time is not reliable, opening research avenues for further development of stable and conductive MXene inks. Such priorities will enable applications requiring high‐resolution and highly reliable printed MXene electronics using state‐of‐the art printing methods. Engineering MXene structural and surface functional properties while tuning MXene ink rheology in benign solvents of choice will be a key for ink developments. This review article summarizes the present status and prospects of MXene inks and their use in inkjet‐printed (IJP) technology for future flexible and bendable MXetronics.

Thin and high conductive multi‐walled carbon nanotubes/polydimethylsiloxane composite film prepared via solvent method as strain sensors

AbstractFlexible strain sensors based on conductive fillers and flexible polymers possessed significant advantages in human motion detection. Preparing a strain sensing layer with high electrical conductivity and excellent mechanical property under high content of conductive filler contributed to the stability of flexible strain sensors. In this study, MWCNTs/PDMS composite film was prepared by the organic solvent method. The microstructure, electrical conductivity, mechanical property, and piezoresistive characteristics of the composite film at different MWCNTs contents were characterized and discussed. When the mass fraction of MWCNTs in the composite film was 5%, the composite film exhibited a high electrical conductivity of 9.56 S/m while maintaining ideal mechanical properties, and the film thickness was just about 180 μm. The relationship between electrical signals and film strain was performed. The piezoresistive characteristic results demonstrated that the prepared composite film could be used as flexible strain sensor for human motion detection. The prepared thin MWCNTs/PDMS composite film in this paper illustrated high conductive and desired flexibility, and was an alternative material for human motion detection.

Hierarchically core-shell structured nanocellulose/carbon nanotube hybrid aerogels for patternable, self-healing and flexible supercapacitors

The flexible and self-healing supercapacitors (SCs) are considered to be promising smart energy storage devices. Nevertheless, the SCs integrated with flexibility, lightweight, pattern editability, self-healing capabilities and desirable electrochemical properties remain a challenge. Herein, an all-in-one self-healing SC fabricated with the free-standing hybrid film (TCMP) composed of the 2,2,6,6-tetramethylpiperidin-1-yloxy-oxidized cellulose nanofibers (TOCNs) carried carbon nanotubes (CNTs), manganese dioxide (MnO2) and polyaniline (PANI) as the electrode, polyvinyl alcohol/sulfuric acid (PVA/H2SO4) gel as the electrolyte and dynamically cross-linked cellulose nanofibers/PVA/sodium tetraborate decahydrate (CNF/PB) hydrogel as the self-healing electrode matrix is developed. The TCMP film electrodes are fabricated through a facile in-situ polymerization of MnO2 and PANI in TOCNs-dispersed CNTs composite networks, exhibiting lightweight, high electrical conductivity, flexibility, pattern editability and excellent electrochemical properties. Benefited from the hierarchically porous structure and high mechanical properties of TOCNs, excellent electrical conductivity of CNTs and the desirable synergistic effect of pseudocapacitance induced by MnO2 and PANI, the assembled SC with an interdigital structure demonstrated a high areal capacitance of 1108 mF cm−2 at 2 mA cm−2, large areal energy density of 153.7 μWh cm−2 at 1101.7 μW cm−2. A satisfactory bending cycle performance (capacitance retention up to 95 % after 200 bending deformations) and self-healing characteristics (∼90 % capacitance retention after 10 cut/repair cycles) are demonstrated for the TCMP-based symmetric SC, delivering a feasible strategy for electrochemical energy storage devices with excellent performance, designable patterns and desirable safe lifespan.

Recent Advances in Dispersant Technology for Carbon Nanotubes toward Energy Device Applications

Carbon nanotubes (CNTs) are of interest in various industries owing to their high aspect ratio, electrical conductivity, and other properties. By maximizing the number of CNTs in their solvents or matrices, the electrical and mechanical performance in applications such as batteries, sensors, and transistors can be enhanced. However, the hydrophobicity of CNTs’ surface induces aggregation that adversely impacts their performance. To overcome this obstacle, many researchers have been designing novel dispersants with performances exceeding that of existing commercial dispersants. This article reviews contemporary studies on CNT dispersants from 2015 to 2022, along with the comprehensive features of CNTs depending on their chirality, number of walls, synthesis methods, and functionalization. Studies of CNT dispersants are primarily organized according to whether aqueous or organic solvents are used. This review article provides a clear perspective of CNT dispersants development today and how to design new CNT dispersants depending on the solvents. A conclusion is given to identify major challenges to the implementation of CNT dispersion and an outlook on future avenues of research.

Understanding Polymerized Ionic Liquids as Solid Polymer Electrolytes for Sodium Batteries.

Solid polymer electrolytes (SPEs) have emerged as promising candidates for sodium-based batteries due to their cost-effectiveness and excellent flexibility. However, achieving high ionic conductivity and desirable mechanical properties in SPEs remains a challenge. In this study, we investigated an AB diblock copolymer, PS-PEA(BuImTFSI), as a potential SPE for sodium batteries. We explored binary and ternary electrolyte systems by combining the polymer with salt and [C3mpyr][FSI] ionic liquid (IL) and analyzed their thermal and electrochemical properties. Differential scanning calorimetry revealed phase separation in the polymer systems. The addition of salt exhibited a plasticizing effect localized to the polyionic liquid (PIL) phase, resulting in an increased ionic conductivity in the binary electrolytes. Introducing the IL further enhanced the plasticizing effect, elevating the ionic conductivity in the ternary system. Spectroscopic analysis, for the first time, revealed that the incorporation of NaFSI and IL influences the conformation of TFSI- and weakens the interaction between TFSI- and the polymer. This establishes correlations between anions and Na+, ultimately enhancing the diffusivity of Na ions. The electrochemical properties of an optimized SPE in Na/Na symmetrical cells were investigated, showcasing stable Na plating/stripping at high current densities up to 0.7 mA cm-2, maintaining its integrity at 70 °C. Furthermore, we evaluated the performance of a Na|NaFePO4 cell cycled at different rates (C/10 and C/5) and temperatures (50 and 70 °C), revealing remarkable high-capacity retention and Coulombic efficiency. This study highlights the potential of solvent-free diblock copolymer electrolytes for high-performance sodium-based energy storage systems, contributing to advanced electrolyte materials.

Binary anion and cation co-doping enhance sulfide solid electrolyte performance for all-solid-state lithium batteries

Sulfide solid electrolytes are regarded as a pivotal component for all-solid-state lithium batteries (ASSLBs) due to their inherent advantages, such as high ionic conductivity and favorable mechanical properties. However, persistent challenges related to electrochemical stability and interfacial compatibility have remained significant hurdles in their practical application. To address these issues, we propose an anion-cation co-doping strategy for the optimization of Li7P3S11 (LPS) through chemical bonding and structural modifications. The co‐doping effects on the structural and electrochemical properties of SiO2-, GeO2-, and SnO2-doped sulfide electrolytes were systematically investigated. Cations are found to preferentially substitute the P5+ of the P2S74- unit within the LPS matrix, thereby expanding the Li+ diffusion pathways and introducing lithium defects to facilitate ion conduction. Concurrently, oxygen ions partially substitute sulfur ions, leading to improved electrochemical stability and enhanced interfacial performance of the sulfide electrolyte. The synergistic effects resulting from the incorporation of oxides yield several advantages, including superior ionic conductivity, enhanced interfacial stability, and effective suppression of lithium dendrite formation. Consequently, the application of oxide-doped sulfide solid electrolytes in ASSLBs yields promising electrochemical performances. The cells with doped-electrolytes exhibit higher initial coulombic efficiency, superior rate capability, and cycling stability when compared to the pristine LPS. Overall, this research highlights the potential of oxide-doped sulfide solid electrolytes in the development of advanced ASSLBs.

A nacre-inspired thermo conductive and healable nanocomposite captures extremely enhanced stiffness and toughness

Polymer-based nanocomposites that exhibit exceptional mechanical properties, rapid self-healing capability, high thermal conductivity, and superior electrical insulation are highly sought after for thermal management applications in modern electrical systems and electronic devices, owing to their versatility, ease of processing, and cost-effectiveness. However, traditional methods for enhancing thermal conductivity often compromise self-healing ability and mechanical and electrical properties. In this study, inspired by nacre, we propose an innovative approach to fabricating nanocomposites with a hierarchical architecture by incorporating boron nitride nanosheets (BNNSs) into a polyurethane matrix through a bottom-up assembly process and lamination technology. Leveraging the nacre-like layered structure and strong interfacial hydrogen bonding interactions, the nanocomposites were successfully transformed from exhibiting brittle fracture to displaying ductile fracture behavior, effectively reconciling the contradiction of high stiffness and toughness. The unique design of the nanocomposite leads to simultaneous enhancement in stiffness (5.3 times), strength (20.1 times), toughness (337.4 times), and fracture toughness (16.4 times) compared to those of the polyurethane matrix. Additionally, the resulting nanocomposites demonstrate excellent self-healing efficiency (∼98 %), high thermal conductivity (8.1 ± 0.3 W m−1 K−1) and superior electrical insulation property (>1012 Ω cm). Overall, our study provides a promising avenue for fabricating polymer-based nanocomposites for thermal management applications, which exhibit multifunctional properties without compromising on mechanical strength, electrical insulation, and self-healing capabilities.

Cold-resistant, highly stretchable ionic conductive hydrogels for intelligent motion recognition in winter sports.

Conductive hydrogels have attracted much attention for their wide application in the field of flexible wearable sensors due to their outstanding flexibility, conductivity and sensing properties. However, the weak mechanical properties, lack of frost resistance and susceptibility to microbial contamination of traditional conductive hydrogels greatly limit their practical application. In this work, multifunctional polyvinyl alcohol (PVA)/carboxymethyl cellulose (CMC)/poly(acrylamide-co-1-vinyl-3-butylimidazolium bromide) (P(AAm-co-VBIMBr)) (PCPAV) ionic conductive hydrogels with high strength and good conductive, transparent, anti-freezing and antibacterial properties were constructed by introducing a network of chemically crosslinked AAm and VBIMBr copolymers into the base material of PVA and CMC by in situ free radical polymerization. Owing to the multiple interactions between the polymers, including covalent crosslinking, multiple hydrogen bonding interactions, and electrostatic interactions, the obtained ionic conductive hydrogels exhibit a high tensile strength (360.6 kPa), a large elongation at break (810.6%), good toughness, and fatigue resistance properties. The introduction of VBIMBr endows the PCPAV hydrogels with excellent transparency (∼92%), a high ionic conductivity (15.2 mS cm-1), antimicrobial activity and good flexibility and conductivity at sub-zero temperatures. Notably, the PCPAV hydrogels exhibit a wide strain range (0-800%), high strain sensitivity (GF = 3.75), fast response, long-term stability, and fantastic durability, which enable them to detect both large joint movements and minute muscle movements. Based on these advantages, it is believed that the PCPAV-based hydrogel sensors would have potential applications in health monitoring, human motion detection, soft robotics, ionic skins, human-machine interfaces, and other flexible electronic devices.

Influence of molecular structure on the coupling strength to a plasmonic nanoparticle and hot carrier generation.

Strong coupling between metal nanoparticles and molecules mixes their excitations, creating new eigenstates with modified properties such as altered chemical reactivity, different relaxation pathways or modified phase transitions. Here, we explore excited state plasmon-molecule coupling and discuss how strong coupling together with a changed orientation and number of an asymmetric molecule affects the generation of hot carriers in the system. We used a promising plasmonic material, magnesium, for the nanoparticle and coupled it with CPDT molecules, which are used in organic optoelectronic materials for organic electronic applications due to their facile modification, electron-rich structure, low band gap, high electrical conductivity and good charge transport properties. By employing computational quantum electronic tools we demonstrate the existence of a strong coupling mediated charge transfer plasmon whose direction, magnitude, and spectral position can be tuned. We find that the orientation of CPDT changes the nanoparticle-molecule gap for which maximum charge separation occurs, while larger gaps result in trapping hot carriers within the moieties due to weaker interactions. This research highlights the potential for tuning hot carrier generation in strongly coupled plasmon-molecule systems for enhanced energy generation or excited state chemistry.

Deep eutectic solvent-based eutectogels consisting of ZnCl2 and lignin for quasi-solid-state supercapacitors

Eutectogels have attracted attention for use in flexible electronics and energy storage because of their high conductivity and good mechanical properties.

High conductivity characteristics of phosphorus-doped nanocrystalline silicon thin films by KrF pulsed excimer laser irradiation method.

The microstructure and high conductivity properties of phosphorus-doped nanocrystalline silicon films were investigated on samples prepared by a plasma-enhanced chemical vapor deposition technique and the KrF pulsed excimer laser irradiation method. The results of Fourier transform infrared spectroscopy and Raman spectroscopy show that Si nanocrystallites with an average diameter of 2 nm to 3 nm are formed in the film. The degree of crystallinity increases with the increase of laser radiation intensity, while the content of hydrogen decreases gradually. More phosphorus atoms are substitutionally incorporated into the nc-Si dots under higher laser irradiation fluence, which is responsible for the high dark conductivity. By controlling the laser fluence at 1.0 J cm-2, the dark conductivity as high as 25.7 S cm-1 can be obtained. Based on the measurements of temperature-dependent conductivity, the carrier transport processes are discussed. The phosphorus doping and the increase of electron concentration are considered to be the reason for high dark conductivity and extremely low conductivity activation energy.

Intercross-linked aramid nanofibers/graphene hybrid films toward high mechanical strength and electrical conductivity

Although macro graphene films exhibit excellent electrical conductivity, the low tensile strength severely hampers the application of graphene films. Combined with polymers can improve the mechanical properties to a degree, but it usually dramatically decreases the electrical conductivities of graphene films. It is thus a great challenge to make a trade-off between high electrical conductivity and excellent mechanical properties of graphene films. Herein, we designed a homogeneous layer-by-layer microstructure combining reduced graphene oxide (rGO) nanosheets with aramid nanofiber (ANF) to obtain composite films referred to as rGO/ANF. By tuning the concentration of ANF, a balanced electrical and mechanical performance can be achieved. It is revealed that the tensile strength of the optimized composite film with 10 wt% ANF was dramatically improved by 194% comparing to the pure rGO film, and the electrical conductivity still maintained at a relatively high level (8495 S m−1). The remarkable overall properties can be attributed to the unique structure with abundant hydrogen bonds and π-π interactions formed between rGO and ANF. The results demonstrate that this is indeed an efficient strategy to balance the electrical conductivity and tensile strength of the graphene-polymer composites, making it promising in the application of multi-functional electronic devices.

Anisotropic Polybenzimidazole Ion‐Solvating Membranes Composed of Aligned Nano‐Sheets for Efficient Acid‐Alkaline Amphoteric Water Electrolysis

AbstractAcid‐alkaline amphoteric water electrolysis (AAA‐WE) can produce green hydrogen under reduced voltage and energy consumption. However, its conflicting demands on ion exchange membranes to have both high ionic conductivity and barrier properties between H+ and OH− have thwarted its own development. Here, the preparation of anisotropic polybenzimidazole (PBI) ion‐solvating membrane (ISM) made of hundreds of 28 nm thick nano‐sheets (PBI‐aNS) from gel state PBI (PBI‐Gel) membranes via 2D‐polarized/1D shrinking process, in which loosely packed multi‐layer PBI nano‐fibrous assemblies are shrunken into hundreds of layers of tight 28 nm thick nano‐sheets, is reported. The resulting PBI‐aNS membranes possess excellent dual‐ion conductivity (H+ and OH−), good acid/alkali barrier capability, and robust mechanical properties. Acid‐alkaline amphoteric water electrolysis (AAA‐WE) using PBI‐aNS separators achieves a high current density of 1 A cm−2 at 1.4 V (with iR‐correction) under a voltage increasing rate of 6.1 mV h−1. This newly designed ISM will lead to new possibilities for the development of next‐generation water electrolysis devices with improved green hydrogen production efficiencies.

Ni-P Electroless Plating of Polyethylene Terephthalate Fibers with Various Twist Number Utilizing Supercritical CO2-Assisted Catalyzation

Weavable devices are multifunctional fabric-based devices prepared by weaving various functional fibers into a single piece of fabric. Metalized polymer fibers are promising electrical conductors for such weavable devices because of the decnet electrical conductivity derived from the metal coating and flexibility arising from the polymer fiber. However, ensuring both sufficient electrical conductivity and stability in these metalized polymer fibers for practical device application remains challenging because of the insufficent adhesion between the metal coating and polymer fiber. An electroless plating with the catalyzation step performed in supercritical carbon dioxide (sc-CO2)1 is developed to produce metallized polymers possessing high electrical conductivity and good adhesive properties between the metal coating and polymer fiber. In application, fibers are often twisted to enhance a specific property, such as the mechanical property, and the twist number (twist per meter, T/m) is expected to affect the electroless plating performance.In this presentation, Ni-P electroless plating of polyethylene terephthalate (PET) fibers with a different twist number (twist per meter, T/m) is reported. The sc-CO2-assisted catalyzation was utilized to achieve electroless plating of Ni-P coatings on the PET fibers. The electrical resistance of the Ni-P/PET fibers was decreased following an increase in the twist number as listed in Table 1. Elemental analyses revealed that the Ni content in the Ni-P coating was higher for the PET fibers with a larger twist number. This tendency corresponded well the the electrical resistance results since Ni-P with a higher Ni content is expected to have a lower electrical resistance. Results obtained in this study indicate that PET fibers with a larger twist number is beneficial for the electroless Ni-P plating by decreasing of the electrical resistance in the fabricated Ni-P/PET fibers. Reference T.-F.M. Chang et al., Microelectron. Eng. 2020, 223, 111233. Figure 1

Performance and Durability of Poly(norbornene) Anion-Conducting Membranes and Ionomers

Low-temperature, polymer-based water electrolyzers using anion conductive polymers have several potential advantages over acid-based polymer electrolyzers. However, the long-term durability of the anion conducting polymer membrane and ionomer remains to be demonstrated.In this study, a family of norbornene-based copolymers and terpolymers have been used in fuel cells and electrolyzers to provide high conductivity (>200 mS/cm at 80oC) and superior mechanical properties. The factors affecting the voltage and durability of alkaline electrolyzers will be reported.

(Invited) Advancing Understanding of Composite Polymer Electrolytes with LLZO Nanofibers

Ceramic Li6.55Al0.2La3Zr2O12 (LLZO) is one of the most attractive electrolyte materials for solid-state batteries that combined with metallic Li anodes holds the promise for safer and more energetically dense battery, but its performance is limited by the increases in electrolyte-electrode interfacial resistances upon cycling. The combination of Li+-conducting ceramics and polymers offers a new pathway to create better electrolytes with both high ionic conductivity and good (electro)mechanical interfacial properties. We optimized two-step annealing processing conditions for the fabrication of low temperature cubic-LLZO nanofibers and Li2CO3 removal from the surface of the nanofibers. Using industrially relevant roll-to-roll electrospinning and slot-die coating, we fabricated thin composite membranes with reproducible thickness down to 50 microns. We investigated PEO based composite polymer electrolyte (CPE) with a high, 50 wt% loading of Al-doped LLZO nanofibers in comparison with nanofiber-free PEO electrolyte. XPS measurements show that LLZO is not present at the composite electrolyte surface, and solid electrolyte interphase (SEI) formation is dictated solely by PEO and LiTFSI when reacting with Li metal. Electrochemical SEI formation, studied by cyclic voltammetry, shows SEI formation is identical with and without up to 75 wt% LLZO in the electrolyte. Galvanostatic cycling with lithium symmetric cells shows that the critical current density (CCD) can be tripled by including 50 wt% LLZO, but half cell cycling reveals this comes at the cost of CE. Varying the LLZO loading shows that even a small amount of LLZO drastically lowers the CE, from 88% at 0 wt% LLZO to 77% at just 2 wt% LLZO. Mesoscale modelling reveals that the increase in CCD cannot be explained by an increase in the macroscopic or microscopic stiffness of the electrolyte; only the microstructure of the LLZO nanofibers in the PEO-LiTFSI matrix slows dendrite growth by presenting physical barriers that the dendrites must push or grow around. This tortuous lithium growth mechanism around the LLZO is corroborated with mass spectrometry imaging. Electrochemical impedance spectroscopy (EIS) analysis showed comparable bulk ionic and interfacial resistances with and without nanofibers, indicating that PEO dominates Li+ transport and interfacial chemistry. The total Li-ion conductivity of the composite is still governed by the polymer matrix due to high interfacial resistance between the garnet particles and the PEO/LiTFSI matrix. This work highlights important elements to consider in the design of CPEs for high-efficiency lithium metal batteries.