Pure Water Research Articles

Understanding wetting behaviors on rough PTFE surfaces towards n-octane/water mixture separation by molecular dynamics simulation

The wetting behaviors of pure n-octane and water nanodroplets on rectangular pitted, grooved, and rectangular pillared polytetrafluoroethylene (PTFE) surfaces were examined by molecular dynamics simulation. The results showed that the three rough surfaces could achieve superlipophilicity and near superhydrophobicity by changing the rough morphology of surface. The n-octane droplets always presented the Wenzel state on the rough surfaces, and the water droplets were the Wenzel state, Transition state and Cassie state under different phase area fractions and/or roughness factors. Based on completely opposite wetting properties of the two droplets on the same surface, separation performances of mixture nanodroplets were further studied on the three rough PTFE surfaces. The results showed that the n-octane/water separation efficiency of pillared surface was above 98.4%, significantly higher than those of pitted and grooved surfaces. The rough PTFE surface with special wettability enabled efficient separation of oil/water mixture. This work is expected to pave the way for the rational design and industrial application of oil/water separation materials.

Efficient Holes Abstraction by Precisely Decorating Ruthenium Single Atoms and RuOx Clusters on ZnIn2S4 for Photocatalytic Pure Water Splitting.

Developing efficient photocatalysts for two-electron water splitting with simultaneous H2O2 and H2 generation shows great promise for practical application. Currently, the efficiency of two-electron water splitting is still restricted by the low utilization of photogenerated charges, especially holes, of which the transfer rate is much slower than that of electrons. Herein, Ru single atoms and RuOx clusters are co-decorated on ZnIn2S4 (RuOx/Ru-ZIS) to employ as multifunctional sites for efficient photocatalytic pure water splitting. Doping of Ru single atoms in the ZIS basal plane enhances holes abstraction from bulk ZIS by regulating the electronic structure, and RuOx clusters offer a strong interfacial electric field to remarkably promote the out-of-plane migration of holes from ZIS. Moreover, Ru single atoms and RuOx clusters also serve as active sites for boosting surface water oxidation. As a result, an excellent H2 and H2O2 evolution rates of 581.9 µmolg-1h-1 and 464.4 µmolg-1h-1 is achieved over RuOx/Ru-ZIS under visible light irradiation, respectively, with an apparent quantum efficiency (AQE) of 4.36% at 400nm. This work paves a new way to increase charge utilization by manipulating photocatalyst using single atom and clusters.

Effects of liquid lubricants on the surface characteristics of 3D-printed polylactic acid

In this study, 3D-printed Polylactic acid (PLA) specimens were manufactured and polished using various lubricants to assess their surface, friction, and wear characteristics. After polishing, the surface roughness decreased by approximately 80% compared with that before polishing, except when acetone was used as the lubricant. In particular, under deionized (DI) water and acetone lubrication conditions, the friction coefficient decreased by 63% and 70%, respectively, whereas the specific wear rate decreased by 88% and 83%, respectively, compared with the unpolished specimens. In the case of dry polishing, adhesion, friction, and wear increase owing to surface damage. Ethanol and IPA polishing resulted in hydrolysis and increased friction, but slightly decreased wear rates. The surface of the specimen polished with acetone dissolved and became very rough. Only the surface polished with DI water exhibited hydrophobic properties. When acetone and DI water were used as lubricants, the surface adhesion force, adhesion energy, friction coefficient, and wear rate were lowest. The finite element analysis results showed that the polished surface exhibited stable contact pressure and friction force, while the unpolished surface showed large fluctuations in contact pressure and friction force owing to the laminated pattern. These results suggest that the polishing process is crucial for improving the surface characteristics and mechanical performance of 3D-printed PLA parts.

Integrating Multipolar Structures and Carboxyl Groups in sp2-Carbon Conjugated Covalent Organic Frameworks for OverallPhotocatalytic Hydrogen Peroxide Production.

The direct production of hydrogen peroxide (H2O2) through photocatalytic reaction via H2O and O2 is considered as an ideal approach. However, the efficiency of H2O2 generation is generally limited by insufficient charge and mass transfer. Covalent organic framework (COFs) offer a promising platform as metal-free photocatalyst for H2O2production due to their potential for rational design at the molecular level. Herein, we integrated the multipolar structures and carboxyl groups into COFs to enhance the efficiency of photocatalytic H2O2 production in pure water without any sacrificial agents. The introduction of octupolar and quadrupolar structures, along with an increase of molecular planarity, created efficient oxygen reduction reaction (ORR) sites. Meanwhile, carboxyl groups could not only boost O2 and H2O2 movement via enhancement of pore hydrophilicity, but also promote proton conduction, enabling the conversion to H2O2 from ·O2-, which is the crucial intermediate product in H2O2 photocatalysis. Overall, we demonstrate that TACOF-1-COOH, consisting of optimal octupolar and quadrupolar structures, along with enrichment sites (carboxyl groups), exhibited a H2O2 yield rate of 3542 μmol h-1 g-1 and a solar-to-chemical (SCC) efficiency of 0.55%. This work provides valuable insights for designing metal-free photocatalysts for efficient H2O2 production.

Misinterpretations about CT numbers, material decomposition, and elemental quantification.

Quantitative CT imaging, particularly iodine and calcium quantification, is an important CT-based biomarker. This study quantifies sources of errors in quantitative CT imaging in both single-energy and spectral CT. This work examines the theoretical relationship between CT numbers, linear attenuation coefficient, and material quantification. We derive four understandings: (1) CT numbers are not proportional with element mass in vivo, (2) CT numbers are proportional with element mass only when contained in a voxel of pure water, (3) iodine-water material decomposition is never accurate in vivo, and (4) for error-free material decomposition a voxel must only consist of the basis decomposition vectors. Misinterpretation-based errors are calculated using the National Institute of Standards and Technology (NIST) XCOM database for: tissue chemical compositions, clinical concentrations of hydroxyapatite (HAP), and iodine. Quantification errors are also demonstrated experimentally using phantoms. In single-energy CT, misinterpretation-induced errors for HAP density in adipose, muscle, lung, soft tissue, and blood ranged from 0-132%, i.e., a mass error of 0-749 mg/cm3. In spectral CT, errors with iodine in the same tissues resulted in a range of < 0.1-33% error, resulting in a mass error of < 0.1-1.2 mg/mL. Our work demonstrates material quantification is fundamentally limited when measured in vivo due to measurement conditions differing from assumed and the errors are at or above detection limits for bone mineral density (BMD) and spectral iodine quantification. To define CT-derived biomarkers, the errors we demonstrate should either be avoided or built into uncertainty bounds. Improving error bounds in quantitative CT biomarkers, specifically in iodine and BMD quantification, could lead to improvements in clinical care aspects based on quantitative CT. CT numbers are only proportional with element mass only when contained in a voxel of pure water, therefore iodine-water material decomposition is never accurate in vivo. Misinterpretation-induced errors ranged from 0-132% for HAP density and < 0.1-33% in spectral CT with iodine. For error-free material decomposition, a voxel must only consist of the basis decomposition vectors.

Reinforced BiOBr for visible-light-driven nitrogen fixation: A synergistic effect of cocatalyst and oxygen vacancies

Photocatalytic nitrogen fixation is a promising long-term strategy for NH3 synthesis, with the development of effective and durable photocatalysts being crucial for achieving high-efficiency N2 to NH3 conversion. In this study, we employed vacancy and interface engineering to create bismuth (Bi) nanoparticles on hierarchical oxygen-deficient BiOBr microspheres using a one-step solvothermal approach. These Bi-decorated BiOBr microspheres, featuring oxygen vacancies, achieved a high photocatalytic ammonia synthesis rate of 222.3 μmol·g−1·h−1 in pure water under visible light irradiation, which is 3.25 times higher than that of the original BiOBr. Atomic-scale images of the interface between the defective regions of BiOBr and the Bi cocatalyst and several other material characterizations confirmed that the enhanced photoreduction activity of Bi/BiOBr is due to the synergistic effects of the metal Bi and the oxygen vacancies. These results present a straightforward and practical method for designing efficient photocatalysts for nitrogen fixation.

Graphene oxide decorated copper nanoparticles embedded polysulfone nanocomposite membrane: Anti-bacterial, organo-bio fouling evaluation in pharmaceutical wastewater treatment via MBR

This study investigates the impact of incorporating graphene oxide (GO) nanosheets and copper nanoparticles decorated reduced graphene oxide (Cu/rGO) on the performance of polysulfone (PSf) membranes in a membrane bioreactor (MBR) system. The characterization of the synthesized nanomaterials confirmed superior antibacterial activity of Cu/rGO compared to GO. Compared to the neat PSf membrane, the prepared nanocomposite membranes exhibited enhanced antibacterial, hydrophilic properties, pure water flux and porosity. Furthermore, the morphological analysis suggested that the GO and Cu/rGO nanohybrids exhibited outstanding interface compatibility and less release (<7%) during 20 days of immersion. During the treatment of the pharmaceutical wastewater in bench scale MBR system, total fouling ratio (TFR) was decreased from 80.24 % for neat PSf membrane to 74.37 % and 67.85 % for PSf-GO and PSf-Cu/rGO membranes, respectively. Notably, the flux recovery ratio (FRR) of the optimized PSf-Cu/rGO and PSf-GO nanocomposite membranes significantly increased 1.44 and 1.25 folds compared to the neat PSf membrane, respectively. The analysis of extracellular polymeric substances indicated an outstanding reduction in protein and carbohydrate concentrations in the cake layer in the presence of nanohybrids, confirming the membranes’ ability to mitigate organic and bio-fouling. These findings suggest GO and Cu/rGO nanohybrids enhance PSf membranes performance in MBR applications.

Performance of capacitive deionizing membrane distillation (CDIMD) process for the organic sewage treatment and how operating parameters can affect it

To solve the fouling issue of traditional membrane distillation (MD) technique, a newly-designed hybrid purification system integrating capacitive deionization (CDI) with MD technology was established for the organic sewage treatment in this study, namely capacitive deionizing membrane distillation (CDIMD) technology. Complexes formation via cross-linking among protein, divalent cations, and polysaccharide, an archcriminal inducing MD fouling, was remarkably alleviated in the CDIMD system considering that negatively-charged organics were clearly divided away from those divalent cations in an electric field circumstance. The CDIMD performance was deeply explored in this study focusing on the impact mechanisms of core operational parameters. An appropriate increment of feed temperature (60–65 °C) and feed flow velocity (15.72–17.82 mm/s) contributed to the anti-fouling performance of CDIMD. Considering the side reactions at voltage >1.2 v, setting working voltage at around 1.2 v seemed to be optimal for CDIMD operation. With an overall consideration of pure water production and anti-fouling performance, a properly thicker CNTs layer (40–60 μm) efficiently enhanced the fouling mitigation of CDIMD. A frequent switching of electric field direction (9/1 min) facilitated the timely regeneration of electrode and composite membranes, accordingly promoting a reliable purification of organic wastewater by CDIMD technique.

Exploring heat transfer augmentation and entropy generation in nanofluid flow induced by vibration: Influence of velocity and rheological properties

This study numerically investigates the heat transfer and entropy generation of nanofluid flow under mechanical vibration, employing approved formulations to model the nanofluid density, specific heat, viscosity, and conductivity. Specifically, the impact of vibration on laminar forced convection thermal flow of both pure water and Al2O3-water nanofluid within a pipe is explored using CFD. Various Reynolds numbers are examined under constant heat flux conditions, with nanofluid properties determined using established correlations. Results indicate that applying Al2O3 nanofluid slurry instead of pure water at low Reynolds numbers reduces entropy generation, proving advantageous. Vibration enhances heat transfer by intensifying fluid agitation and promoting particle dispersion near the wall, resulting in a significantly more uniform temperature distribution along the pipe, approximately 100 times more than steady-state flow. Analysis reveals vibration’s effectiveness in reducing irreversibility, especially at lower Reynolds numbers, with substantial enhancements in heat transfer coefficients, up to approximately fivefold compared to steady-state flow, particularly for nanofluid flows. Optimal conditions for maximizing heat transfer enhancement emphasize nanoparticle size and concentration. Mechanical vibration with different frequencies produces significant improvements in heat transfer compared to amplitude variations, primarily influenced by the Reynolds number. Overall, this study offers valuable insights into the intricate relationship between vibration, fluid dynamics, and heat transfer in nanofluid flows, with practical implications for optimizing thermal management systems across various engineering applications.

Effect of complex ionic liquid additives on the formation kinetics and separation efficiency of binary gas mixture hydrates

Rising carbon emissions worldwide have necessitated the discovery of efficient CO2 separation and capture technologies. Owing to their good CO2 selectivity, imidazolium-based ionic liquids (ILs) have been used as additives in hydrate-based gas separation (HBGS) technologies. Sodium dodecyl sulfate (SDS) can notably improve the rate of hydrate formation when used as a surfactant. However, the synergistic effect of imidazolium-based ILs and SDS remains unknown. This study aimed at investigating the synergistic effect of imidazolium-based ILs and SDS on the hydrate formation kinetics of binary gas mixtures of CO2/N2 at different temperatures. The carbon capture and storage capacity was determined, and HBGS was evaluated using pure imidazolium-based IL 1-butyl-3-methylimidazolium octyl sulfate ([BMIM] [OS]) and composites of IL and SDS as additives. Compared with pure water, [BMIM] [OS] effectively promoted gas hydrate formation and increased CO2 consumption by 107.9 %. The maximum CO2 separation factor was obtained at 273.15 K, and the mixed additive significantly enhanced gas consumption by 11.1 %. X-ray diffraction and Raman spectroscopy analysis indicated that the hydrate samples were type I structural hydrates and that [BMIM] [OS] improved the mass transfer process. The results of this study provide a theoretical basis for CO2 gas separation and capture.

Online monitoring of solubility of Li2CO3 in the NaCl–KCl–Na2SO4 system

ABSTRACT The solubility and thermodynamics of lithium carbonate (Li2CO3) play an important role in industrial crystal production. The solubility of Li2CO3 in H2O, NaCl, KCl, Na2SO4 and mixed NaCl–KCl–Na2SO4 solutions is measured, respectively, at temperatures ranging from 293.15 K to 368.15 K using the gravimetric method and immersion infra-red probe. The results suggested that the solubility of Li2CO3 exhibits a decreasing trend with increasing temperature. The impurity composition such as NaCl, Na2SO4 and NaCl–KCl–Na2SO4 can significantly affect the solubility of Li2CO3. It is higher than that in pure water, and the addition of KCl decreases its solubility in the temperature ranging from 293.15 K to 313.15 K. The Van’t Hoff and modified Apelblat models are further employed to correlate the solubility data of Li2CO3 in different systems. In addition, the thermodynamic data of Li2CO3 are calculated, which shows a non-spontaneous exothermal process and entropy reduction.

Simultaneous enhanced antibiotic pollutants removal and sustained permeability of the membrane involving CoFe2O4/MoS2 catalyst initiated with simple H2O2 backwashing

Membranes for wastewater treatment should ideally exhibit sustainable high permeate production, enhanced pollutant removal, and intrinsic physical rejection. In this study, CoFe2O4/MoS2 serves as a non-homogeneous phase catalyst; it is combined with polyether sulfone membranes via liquid-induced phase separation to simultaneously sustain membrane permeability and enhance antibiotic pollutant degradation. The prepared catalytic membranes have higher pure water flux (329.34 L m−2 h−1) than pristine polyethersulfone membranes (219.03 L m−2 h−1), as well as higher mean pore size, porosity, and hydrophilicity. Under a moderate transmembrane pressure (0.05 MPa), tetracycline (TC) in synthetic and real wastewater was degraded by the optimal catalytic membrane by 72.7 % and 91.2 %, respectively. Owing to the generation of the reactive oxygen species (ROS) during the Fenton-like reaction process, the catalytic membrane could exclude the natural organics during the H2O2 backwash step and selectively promote fouling degradation in the membrane channel. The irreversible fouling ratio of the catalyzed membrane was significantly reduced, and the flux recovery rate increased by up to 91.6 %. A potential catalytic mechanism and TC degradation pathways were proposed. This study offers valuable insights for designing catalytic membranes with enhanced filtration performance.

Room‐Temperature Afterglow Nanostructures via Block Copolymer Self‐Assembly

AbstractMiniaturization of organic afterglow materials has shown promising application in biomedical and other areas. Current technologies, such as nanoprecipitation, mechanical treatment, and emulsion polymerization, lack the capability of facile control on the morphology and dimension of the miniaturized organic afterglow materials. Here we report the fabrication of organic afterglow nanostructures via block copolymer self‐assembly at room temperature. The fabrication is based on two‐component design strategy where hydrophobic luminescent emitters with small rate constants of phosphorescence decay or reverse intersystem crossing are designed as the first component. Amphiphilic block copolymers that can form spherical core‐shell micelles and worm‐like micelles with glassy hydrophobic cores are used as the second component. Upon addition of water into a dimethylformamide solution that contains the two components, the amphiphilic block copolymers self‐assemble into well‐defined nanostructures and accommodate the hydrophobic luminescent emitters in nanostructure's hydrophobic cores. After switching to pure water by dialysis, room‐temperature afterglow nanostructures have been obtained because of the excellent protection of organic triplets by the glassy hydrophobic cores. The afterglow nanostructures exhibit intriguing afterglow mechanism modulated by the types of luminescent emitters, controlled dimensions and morphologies by the structural parameters of the block copolymers.

Changing Benzoxazole Ring into Nonring Imine Linkages on Covalent Organic Frameworks with Tuning H2O2 Photosynthesis Performance.

Two π-conjugated covalent organic frameworks (COFs) with nonring imine or benzoxazole ring linkages were prepared by reacting 3,3'-dihydrooxybenzidine (BDOH) with 3,5-triformylbenzene (Tb) in the presence or absence of benzimidazole (BDOH-Tb-IM and BDOH-Tb-BO). Although two COFs indicated similar composition, crystalline structures, and morphologies, imine-based BDOH-Tb-IM exhibited a photocatalytic H2O2 production rate of 2490 μmol·g-1·h-1 in sacrificial reagent-free pure water, higher than that of benzoxazole-based BDOH-Tb-BO-a (1168 μmol·g-1·h-1). The higher photocatalytic activity of BDOH-Tb-IM was attributed to its more efficient photoinduced charge separation and utilization efficiency and different 2e- ORR active sites over the two COFs. This study demonstrated an available ring effect to adjust photocatalytic performance between π-conjugated COFs.

Screening factors to affect ultrasound-assisted extraction of (poly)phenols from date palm seeds

The aim of the current work was to compare the (poly)phenol profile (free, soluble-conjugate, and insoluble-bound) and antioxidant activity of date palm seed flour using different extraction methods (conventional vs. ultrasound-assisted extraction [UAE]) and to determine the most critical variables in the extraction of (poly)phenols through UAE using the Plackett–Burman design experiment. Using the Plackett–Burman design, seven factors, namely, ethanol concentration, liquid:solid ratio (mL/g), sonotrode, amplitude (%), extraction time, extractant pH, and extraction cycle, were studied. After the factors were studied using conventional extraction methods, 23 compounds were quantified, with protocatechuic acid and catechin being the predominant (poly)phenols. Furthermore, the distribution of (poly)phenols within the cell varied, with glycosylated quercetins and caffeoyl shikimic acids predominantly found in free forms. Ultrasound-assisted extraction demonstrated efficiency in extracting free and soluble-conjugate (poly)phenols. However, it showed limitations in extracting insoluble-bound (poly)phenols. Nevertheless, similar amounts of total (poly)phenols were shown after conventional extraction and UAE, that is, 259.69 ± 43.54 and 189.00 ± 3.08 mg/100 g date seed flour, respectively. The Plackett–Burman design revealed the liquid–solid ratio as a crucial factor affecting (poly)phenol extraction, with higher ratios yielding better results. The sonotrode choice also influenced the extraction efficiency, highlighting that the sonotrode with a smaller diameter but higher displacement amplitude showed the best polyphenol recovery and antioxidant activity values. The nature of (poly)phenols influenced the studied extraction variables differently, emphasizing the complexity of the extraction process. In this line, pure water was sufficient to extract flavan-3-ols after UAE, whereas ethanol was a crucial factor in extracting quercetin. These findings underscore the importance of optimizing extraction methods for maximizing (poly)phenol recovery from date palm seed flour for various applications in food and pharmacology industries.

Facile preparation of graphene-graphene oxide liquid cells and their application in liquid-phase STEM imaging of Pt atoms

Abstract Graphene-graphene oxide (GO) hybrid liquid cells (LCs) for liquid-phase scanning transmission electron microscopy (STEM) were fabricated using a facile method with commercial graphene on a polymethyl methacrylate sheet and GO on a TEM grid. LCs containing Pt nanoparticles (NPs) and pure water were efficiently produced and observed via STEM. Their composition and thickness were characterized by STEM-electron energy-loss spectroscopy. High-resolution (HR) STEM revealed slow-moving Pt NPs’ atomic structures and fast-moving single Pt atoms at the LC’s thin edges. Minimal damage during HR STEM indicated stable LCs because of their excellent electrical and thermal conductivities and radiolysis species scavenging ability.

Ultra-stable, lightweight and superelastic waste flax-based aerogel for multifunctional applications

Multifunctional aerogels constructed from natural waste biomass have attracted great attention in the fields of green energy harvesting, flexible wearable sensing and natural environment restoration. However, the complex and polluted extraction of natural materials and the poor mechanical property have seriously hindered the development of natural material-based aerogels. Hence, a novel aerogel with capabilities of high-elasticity, stabilized constructions and weightlessness was prepared via waste flax staple fibers (simply physically disrupting) and multi-walled carbon tubes. Due to the assistance of cross-linking agent and carbon tubes, the aerogel was endowed with multiple properties including high photothermal conversion (97.2 %), superstability at the wide range of 0–29 KPa and outstanding compression resilience at different strains (up to 60 % and 100 cycles). Consequently, it is promising that the fabricated aerogel may be as a piezoresistive sensor to monitor different locations of the body for continuous detection of motor behavior. Further, the sample was also utilized as an evaporator with excellent water evaporation effect (1.93 kg·m−2·h−1) under 1 sun and to efficiently purify various types of wastewater for obtaining pure water. This multi-purpose aerogels prepared in this work display admirable potential for efficient environmental purification, advanced smart materials and green energy harvesting.

Effect of layered double hydroxide-graphene oxide modifier composition on characteristics of polyvinylidene fluoride based nanocomposite membranes in the separation of Cu2+

This research explored the modified polyvinylidene fluoride (PVDF) nanofiber membranes with a composite of layered double hydroxide (LDH) and graphene oxide (GO) to enhance biofouling resistance. The PVDF/LDH-GO nanocomposite membranes were synthesized via vacuum filtration. FTIR analysis confirmed nanocomposite formation with new peaks indicating the presence of GO and LDH. Variations in the LDH:GO ratio affected the physical, mechanical, and performance properties of the membranes. Based on SEM imaging, the 1:1 LDH: GO ratio exhibited the highest Young's modulus and smallest pore sizes. LDH-GO incorporation increased the mechanical strength, porosity, roughness, hydrophilicity, and pure water permeability of the PVDF membranes. The combination of these factors led to balanced permeability and selectivity values towards Cu2+ solution feeds. LDH-GO was proven effective in modifying the PVDF membrane surface for water treatment and inhibiting biofouling up to 64% against E. coli.

Enhancing Sustainability in PLA Membrane Preparation through the Use of Biobased Solvents

For the first time, ultrafiltration (UF) green membranes were prepared through a sustainable route by using PLA as a biopolymer and dihydrolevoclucosenone, whose trade name is Cyrene™ (Cyr), dimethyl isosorbide (DMI), and ethyl lactate (EL) as biobased solvents. The influence of physical-chemical properties of the solvent on the final membrane morphology and performance was evaluated. The variation of polymer concentration in the casting solution, as well as the presence of Pluronic® (Plu) as a pore former agent, were assessed as well. The obtained results highlighted that the final morphology of a membrane was strictly connected with the interplaying of thermodynamic factors as well as kinetic ones, primarily dope solution viscosity. The pore size of the resulting PLA membranes ranged from 0.02 to 0.09 μm. Membrane thickness and porosity varied in the range of 0.090–0.133 mm of 75–87%, respectively, and DMI led to the most porous membranes. The addition of Plu to the casting solution showed a beneficial effect on the membrane contact angle, allowing the formation of hydrophilic membranes (contact angle &lt; 90°), and promoted the increase of pore size as well as the reduction of membrane crystallinity. PLA membranes were tested for pure water permeability (10–390 L/m2 h bar).

Amorphous Boron Nitride Nanosheet‐Based Solid State Electrolytes with High Ionic Conductivity

AbstractAmorphous boron nitride nanosheets, with natural electrical insulation, outstanding chemical stability and mechanical properties, are introduced as a matrix to be incorporated with lithium bis (trifluoromethanesulfonyl) imide (LiTFSI) and polymer polyvinylidene fluoride‐hexafluoropropylene copolymer (PVDF‐HFP), for constructing a novel composite solid‐state electrolyte by a simple solution‐casting method. Amorphous boron nitride nanosheets are produced via a combination method of ball milling and pure water exfoliation. The obtained composite solid‐state electrolyte containing 40 % (mass fraction) PVDF‐HFP shows a high lithium ion conductivity (1.936×10−3 S cm−1) and lithium ion transference number (0.47), and a wide electrochemical stability window (5 V) at room temperature. The LiFePO4/Li based all solid‐state battery, consisting of the composite solid electrolyte (40 % PVDF‐HFP), delivers a capacity of 128.1 mAh g−1, a Coulombic efficiency of 99.79 % after 500 cycles and a capacity retention rate of 94.5 % at 1.0 C and 25 °C. The composite solid electrolyte (40 % PVDF‐HFP) can maintain flat and stable stripping/plating plateaus for over 800 hours in symmetrical cells. The amorphous boron nitride nanosheets with high lithium ion conductivity are employed to construct solid‐state electrolytes, which is important significant for the development of high energy density, high safety, and long cycle life all‐solid‐state lithium‐ion batteries.