Surface Sol-gel Research Articles

Development of a universal sol–gel sorbent for fabric phase sorptive extraction and its application in tandem with high performance liquid chromatography-ultraviolet detection for the analysis of phthalates in environmental and drinking water samples

Most sorbent-based sample preparation methods are designed to interact with a class of analytes i.e., a polar sorbent for polar analytes, a non-polar sorbent for non-polar analytes, an ion-exchange sorbent for ionized compounds. A big challenge surfaces when making a choice of an appropriate sorbent when there is a mixture of compounds of varying polarities and ionization states in the complex sample matrices. Hence, the aim of this study was to develop a universal sol–gel sorbent coating for fabric phase sorptive extraction that would effectively and simultaneously extract polar, nonpolar, organic acids and bases via different intermolecular/interionic interactions. The universal sol–gel sorbent coated fabric phase sorptive extraction membrane was created by exploiting sol–gel surface coating technology to implant different functional moieties, ion exchanging ligands and an organic polymer that results in a 3-D organic–inorganic hybrid structure on the fabric substrate with a high level of selectivity/affinity for the target compounds. The preconcentrated extracts containing the isolated phthalates after the fabric phase sorptive extraction procedure were injected into the high-performance liquid chromatography-ultraviolet detection (HPLC-UV) system for the quantification. The FPSE-HPLC-UV method demonstrated a linear range between 50 and 1000 ng/mL for dimethyl phthalate, diethyl phthalate, dipropyl phthalate, diallyl phthalate, benzyl butyl phthalate, 1–10000 ng/mL for di-n-heptyl phthalate, 1–5000 ng/mL for di-n-heptyl phthalate, 10–5000 ng/mL for di-n-ethyl hexyl phthalate and 100–7500 ng/mL di-n-octyl phthalate. The intra-day and inter-day reproducibility (in terms of percentage relative standard deviation, %RSD) did not exceed 13.6. This method proves to be a selective, accurate, reproducible, cheap, and fast analytical approach for the quantitative and qualitative determination of the phthalates which is useful in crafting regulations for phthalates content in beverages and juices as well as in environmental monitoring.

Selective Adsorption of Quercetin by the Sol-Gel Surface Molecularly Imprinted Polymer.

Quercetin, as one of the most biologically active natural flavonoids, is widely found in various vegetables, fruits and Chinese herbs. In this work, molecularly imprinted polymer (MIP) was synthesized through surface molecular imprinting technology with sol-gel polymerization mechanism on SiO2 at room temperature using quercetin as the template, SiO2 as the supporter, 3-aminopropyltriethoxysilane (APTES) as the functional monomer, and tetraethoxysilane (TEOS) as the cross-linker. The prepared MIP was characterized via scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR) and nitrogen adsorption measurements to validate its surface morphology, structure and functionality. SEM images revealed that the morphology of MIP was rough and spherical with the particle size of 260 nm larger than that of the support SiO2. In the FTIR spectra of MIP, the band around 1499 cm-1 and 2932 cm-1 were assigned to N-H and C-H groups, respectively. The results indicated that the imprinted polymer layers were grafted on the surface of SiO2 and the MIP had been successfully prepared. Since the specific surface area and pore volume of MIP were markedly higher than those of NIP and SiO2 and were 52.10 m2 g-1 and 0.150 cm3 g-1, respectively, it was evident that the imprinting process created corresponding imprinted cavities and porosity. The MIP for adsorbing quercetin was evaluated by static adsorption experiment. The results indicated that the adsorption equilibrium could be reached within 90 min and the maximum adsorption capacity was as high as 35.70 mg/g. The mechanism for adsorption kinetics and isotherm of MIP for quercetin was proved to conform the pseudo-second-order kinetics model (R2 = 0.9930) and the Freundlich isotherm model (R2 = 0.9999), respectively, revealing that chemical adsorption and heterogeneous surface with multilayer adsorption dominated. In contrast to non-imprinted polymer (NIP), the MIP demonstrated high selectivity and specific recognition towards quercetin whose selectivity coefficients for quercetin relative to biochanin A were 1.61. Furthermore, the adsorption capacity of MIP can be maintaining above 90% after five regeneration cycles, indicating brilliant reusability and potential application for selective adsorption of quercetin.

The influence of N-based group doping on surface potential of TiO2 electron transport layer prepared by Sol-gel and sputtering techniques

• E T L T i O 2 were prepared by Sol-gel and DC-PMS techniques, respectively. • (0 0 1) lattice in E T L S o l - g e l T i O 2 was random. • (0 0 1) lattice in E T L D C - P M S T i O 2 was parallel to the surface. • (0 0 1) lattice plane restrain the diffusion of N + or NH x + in E T L T i O 2 . • N + or NH x + diffusion has little influence on band structure of E T L D C - P M S T i O 2 . TiO 2 ETL were prepared by DC-PMS and Sol-gel techniques respectively, which could be used in perovskite solar cells. N + and NH x + ions/group beam was used to bombard the surface of Sol-gel and DC-PMS TiO 2 ETLs. After the bombardment, the surface potential and sheet carrier concentration of Sol-gel TiO 2 ETL obviously deteriorated from 4.66 to 4.43 eV and 2.17 to 0.41 (10 11 /cm 2 ), respectively. On the contrary, little deterioration happened onto the surface potential and sheet carrier concentration of DC-PMS TiO 2 ETL, which decreased from 4.81 to 4.79 eV and 2.02 to 1.63 (10 11 /cm 2 ), respectively. Besides, the deterioration of surface potential and sheet carrier concentration for Sol-gel and DC-PMS TiO 2 ETLs was discussed.

Preparation, characterization, and biocompatibility of chondroitin sulfate-based sol-gel coatings and investigation of their effects on osseointegration improvement

In this work, implants with enhanced antibacterial and surface properties besides mechanical, biological, and chemical properties were prepared with the replacement of traditional titanium and titanium alloys in the field of biomedical materials. Titanium substrates were coated with chondroitin sulfate (CS) containing (3-glycidoxypropyl)trimethoxysilane (GLYMO) and tetraethoxysilane (TEOS) based thin film using sol-gel technology. Chondroitin sulfate is a preferred material due to its characteristics antioxidative and osseointegresion properties besides its collagen-forming properties. Coated implants were morphologically elucidated with atomic force microscopy (AFM), and scanning electron microscopy (SEM). The structure of the chondroitin sulfate-containing films was investigated with Fourier Transform Infrared Spectroscopy (FTIR) and Energy Dispersive X-Ray Analysis (EDX) techniques. The obtained CS-based sol-gel surface coatings are thermally stable up to ∼200 °C according to TGA and DTA analysis results. The biological and antibacterial properties of the coatings were also determined. The biocompatibility and osseointegration properties of the coatings developed within the scope of the study were, determined by in vivo studies on rats. According to biocompatibility results of CS/Sol-Gel coated surfaces, Cell viability (%) rates of CS-based coatings showed between 89 and 66%. According to the experimental data, it has been claimed that implants improved with antibacterial, stable, homogeneous, and biocompatible coatings can be used as a new alternative product for dental and orthopedic applications.

Superior flame retardancy, antidripping, and thermomechanical properties of polyamide nanocomposites with graphene‐based hybrid flame retardant

AbstractGraphene is considered one of the most prominent halogen‐free multifunctional flame retardants for polymers, and the resultant nanocomposites also display a good balance of properties. However, the biggest concern nowadays is thermal oxidative degradation, which mainly affects the flame retardant (FR) efficiency of graphene. To improve the flame retardancy and thermal oxidative degradation efficiency, graphene was functionalized with a combination of polycyclotriphosphazes and siloxanes via a sol–gel surface modification method, yielding a graphene‐based hybrid FR (PSGO) containing multiple elements (P, N, S, and Si). The PSGO‐containing PA6 composite exhibited significant improvements in the water resistance, thermal, mechanical, and FR properties, as compared with those of 3‐isocyanatopropyltriethoxysilane functionalized graphene oxide (ITS‐GO) and siloxane‐modified polycyclotriphosphazenes (m‐PZS) individually. The peak heat release rate and total heat release values of the PA6 composites with 10 wt% PSGO decreased by 45.7% and 36.9%, respectively, compared to those of pristine PA6. Moreover, it was confirmed that 10 wt% PSGO in the PA6 composite resulting in a V–0 rating in the UL‐94 tests, even after the water immersion test. These attractive properties are attributed to the resistance to thermal‐oxidative degradation of PSGO and the improved interfacial interactions with the polymer matrix. Therefore, this PSGO can be used as a multifunctional modifier to improve the water resistance, thermal, mechanical, and FR properties of polymers.

Dye fluorescence enhancement by plasmonic nanostructured gold–titania film composites obtained by the combination of electrodeposition and surface sol-gel process

Dye fluorescence enhancement by plasmonic nanostructured gold–titania film composites obtained by the combination of electrodeposition and surface sol-gel process

Precision surface modification of solid oxide fuel cells via layer-by-layer surface sol–gel deposition

A surface sol–gel process is applied to deposit a precisely-controlled PrOx catalyst coating on porous La0.6Sr0.4Co0.2Fe0.8O3−δ electrodes, greatly enhancing the electrocatalytic activity and durability.

The effect of Al element on structural, optical, electrical, surface and photocatalytic properties of Sol-gel derived ZnO films

The effect of Al element on structural, optical, electrical, surface and photocatalytic properties of Sol-gel derived ZnO films

Antimicrobial Activity of a Novel Cu(NO3)2-Containing Sol-Gel Surface under Different Testing Conditions.

In this study, assessment of the antimicrobial activity of a novel, plasma-cured 2.5% (w/v) Cu(NO3)2-containing sol–gel surface was performed. In contrast to state-of-the-art sol–gel coatings, the plasma curing led to a gradient in cross-linking with the highest values at the top of the coating. As a result, the coating behaved simultaneously hard, scratch-resistant, and tough, the latter due to the more flexible bulk of the coating toward the substrate. Further, the diffusion and permeation through the coating also increased toward the substrate. In our study, tests according to ISO 22196 showed antibacterial activity of the 2.5% (w/v) Cu(NO3)2-containing sol–gel surface against all bacterial strains tested, and we expanded the testing further using a “dry” evaluation without an aqueous contact phase, which confirmed the antimicrobial efficacy of the 2.5% (w/v) Cu(NO3)2-containing sol–gel surface. However, further investigation under exposure to soiling with the addition of 0.3% albumin, used to simulate organic load, led to a significant impairment in the antibacterial effect under both tested conditions. Furthermore, re-testing of the surface after disinfection with 70% ethanol led to a total loss of antibacterial activity. Our results showed that besides the mere application of an antimicrobial agent to a surface coating, it is also necessary to consider the future use of these surfaces in the experimental phase combining industry and science. Therefore, a number of tests corresponding to the utilization of the surface should be obligative on the basis of this assessment.

Tacrolimus encapsulated mesoporous silica nanoparticles embedded hydrogel for the treatment of atopic dermatitis

Atopic dermatitis (AD) is a repetitive inflammatory skin disorder with limited treatment options. Innovative targeted therapies are gaining significant interest and momentum towards disease control including better ways to deliver drugs topically. Tacrolimus is one such compound which is used to manage moderate to severe AD without causing atrophy which is one of the common side effects of steroids. However, Tacrolimus suffers from poor solubility and retention in the skin when used alone in hydrogel. Therefore, we have prepared Tacrolimus loaded mesoporous silica nanoparticles (TMSNs) to overcome the issues related to its solubility and effective topical delivery. Mesoporous silica nanoparticles (MSNs) were synthesized using sol gel technique and surface functionalized using amino (–NH2+) and phosphonate (-PO3-) groups. Tacrolimus was loaded into MSNs and the particles were characterized for particle size (TEM and DLS), zeta potential (DLS), solubility studies, FTIR, TGA, XRD, BET and cytotoxicity studies. Water solubility of Tacrolimus was increased by 7 folds with phosphonate functionalized MSNs compared to free Tacrolimus. Further the TMSNs were incorporated in to carbopol gel, and the gel formulation was evaluated for various gel characterization tests (pH, spreadability, viscosity), in vitro tests (drug release, permeability studies) and in vivo tests (skin irritation study and efficacy studies) using 1-Fluoro-2,4-dinitrobenzene (DNFB) induced dermatitis in Balb/c mice. Results of in vitro and in vivo study showed that TMSNs loaded gel showed significantly higher amount of Tacrolimus retained (ex vivo – rat skin) and much higher reduction in ear thickness and improved histology (in vivo - in mice). Our data collectively suggest that MSNs incorporated hydrogel as a promising new formulation strategy for topical delivery of poorly soluble drugs.

Reinforced Composite Membranes Based on Expanded Polytetrafluoroethylene Skeletons Modified by a Surface Sol–Gel Process for Fuel Cell Applications

Reinforced Composite Membranes Based on Expanded Polytetrafluoroethylene Skeletons Modified by a Surface Sol–Gel Process for Fuel Cell Applications

Accelerating the Design of β-CD-PVDF-based Molecularly Imprinted Nanocomposite Membrane for Selective Separation: A Surface Functional Monomer-Directing Strategy

Enoxacin, as the broad-spectrum antibacterial activity antibiotics, has been widely used in treatment of bacterial diseases in animals and humans around the world. The extensive use of enoxacin in healthcare has also caused increasingly serious environmental risk as a matter of course. In this work, enoxacin imprinted poly (vinylidene fluoride) (PVDF) composite membranes (EIPCMs) were developed by strategy of surface grafting beta-cyclodextrin ([Formula: see text]-CD) for the improved hydrophilic and antifouling properties of the basal membrane. PVDF membrane was prepared by phase inversion method, and [Formula: see text]-CD was grafted onto the surface after hydroxyl groups modification. The effects of adding amount of [Formula: see text]-CD on performance of basal membranes were systematically examined. Further, the specific recognition sites were fabricated via sol–gel surface imprinting method using 3-aminopropyltriethoxysilane (APTES) and tetraethoxysilane (TEOS) as functional monomer and cross-linker, respectively. The specific adsorption and permeation experiments were investigated and explored the separation performance and mechanism of EIPCM. The results indicated that the as-prepared EIPCMs not only exhibited highly favorable features and high rebinding strength (31.25[Formula: see text]mg g[Formula: see text], but also possessed superior selective performance toward enoxacin (imprinted factor [Formula: see text] is 3.15). Furthermore, in order to investigate the practical applications of EIPCMs, the adsorption experiments were carried out using environmental sewage. The work developed here shows great potential for further applications in selective recognition and separation antibiotics pollution from the environment.

Seeded Growth Synthesis of Zirconia@Gold Particles in Aqueous Solution.

Metal-ceramic composite particles are of increasing interest due to their potential applications in photonic metamaterials as well as next-generation catalysts. The zirconia-gold system has received little attention due to the lack of controllable preparation methods. Well-known methods for the deposition of gold nanoshells on silica spheres, however, should be adaptable for similar zirconia-based materials. Here, we present a novel synthetic approach to the well-controlled deposition of gold on the surface of sol-gel derived zirconia mesoparticles by a stepwise method involving the immobilization of gold nanoparticles and repeated seeded-growth steps. We show that the immobilization efficiency is strongly enhanced by acidification with hydrochloric acid and additional employment of aminomethylphosphonic acid as coupling agent. The optimum conditions are identified and the subsequent incremental growth by seeded reduction of gold is demonstrated. The results shed light on the parameters governing the preparation of zirconia@gold composite particles and our synthetic approach provides a promising tool for future developments in complex nanomaterials design.

Fabrication and photocatalytic behavior of titanium oxide–gold nanoparticles composite ultrathin films prepared using surface sol–gel process

Ultrathin films consisting of titanium oxide and gold nanoparticles were prepared using a combination of the surface sol–gel process and liquid/liquid interfacial precipitation. The composite films had a titanium oxide/gold nanoparticle layer/titanium oxide film structure, comprising a gold nanoparticle thin-film layer sandwiched within titanium oxide films of nanometer-order thickness. Upon heating the titanium oxide–gold nanoparticle composite films to 450 °C, they underwent a phase change from the amorphous to the anatase phase, which was confirmed via Raman scattering analysis. It was observed that, even after heating, the plasmonic absorption band due to the presence of gold nanoparticles was maintained in the composite films. The photocatalytic degradation efficiencies of methylene blue dye were evaluated in films under 520 nm light irradiation. The results suggested that the sandwich-like structure of this titanium oxide/gold nanoparticle layer/titanium oxide is promising for the visible-light-induced degradation of methylene blue dye.

TiO2 Sol-Gel Coated PAN/O-MMT Multi-Functional Composite Nanofibrous Membrane Used as the Support for Laccase Immobilization: Synergistic Effect between the Membrane Support and Enzyme for Dye Degradation.

Removal of a triphenylmethane dye (crystal violet, CV) by a simultaneous enzymatic-photocatalytic-adsorption treatment was investigated in this work. A desirable synergistic effect on dye treatment was achieved by decorating laccase (Lac) onto the surface of TiO2 sol-gel coated polyacrylonitrile/organically modified montmorillonite (PAN/O-MMT) nanofibers prepared by electrospinning. The assembly of Lac on the surface of PAN/O-MMT/TiO2 nanofibers was confirmed by confocal laser scanning microscope (CLSM). In comparison with free Lac, the immobilized Lac showed better pH, temperature and operational stabilities, reaching highest relative activity at an optimum pH of 3 and optimum temperature of 50 °C. Therefore, the immobilized Lac displayed a higher degradation efficiency of CV at an initial dye concentration of 100 mg/L, an optimum pH of 4.5 and temperature at 60 °C. Under UV illumination, the CV removal efficiency was further improved by ~20%. These results demonstrated that the Lac-immobilized PAN/O-MMT/TiO2 composite nanofibers with a combined effect between the immobilized enzyme and the polymeric support have potential for industrial dye degradation.

A bio-inspired nanofibrous Co3O4/TiO2/carbon composite as high-performance anodic material for lithium-ion batteries

A bio-inspired nanofibrous Co3O4/TiO2/carbon composite was fabricated using natural cellulose substrate (laboratory filter paper) as both the carbon source and the structural scaffold. Employing a surface sol–gel process to form a thin TiO2 gel layer coating on each cellulose nanofiber of the filter paper, the resulted composite sheet was successively carbonized in inert atmosphere to give a nanofibrous TiO2/carbon composite; afterwards, nano-sized Co3O4 particles (10–30 nm) were uniformly deposited onto the yielded composite fibers via a simple hydrothermal method, resulting in the Co3O4/TiO2/carbon hybrid. The ternary composite possessed a unique hierarchically three-dimensional porous structure which inherited precisely from the initial filter paper. This special structure with the internal conductive carbon fiber and the external nano-sized Co3O4 particles offered the nanocomposite with an excellent electrochemical performance as anodic material for lithium-ion batteries. The optimal sample with a Co3O4 mass content of 50.6% delivered an initial discharge capacity of 1239 mAh g−1 at a current density of 100 mA g−1, which was far exceeded the theoretical capacity of Co3O4. The extra capacity is ascribed to the additional lithium storage sites provided by the large specific surface area of the composite, and the formation of the solid electrolyte interface (SEI) layer in the initial discharge process causing a large consumption of Li+ which results in some irreversible capacity. And after 200 discharge/charge cycles, a high reversible capacity of 764 mAh g−1 was maintained, which is higher than most of the Co3O4/carbon hybrid materials reported. This work provided a simple and efficient strategy for designing and preparing nanoscale metal-oxide/carbon composite material with considerable potential in energy storage and conversion.

Sol-Gel Fabricated Tio₂ Coating on Titanium Surface Promoted In Vitro Osteoblasts Differentiation.

Titanium has been used for biomedical devices due to its excellent biocompatibility, which is based partly on its 2-8 nm thick titanium oxide layer. However, the relatively poor surface hardness, wear resistance and metal release of these layers may cause some problems in clinical application. In this study, titanium surfaces were modified using a TiO₂ sol-gel coating, in order to improve surface properties and osteoblast function. No significant difference in surface roughness was observed between titanium and TiO₂ sol-gel discs. The surface of TiO₂ sol-gel discs possessed more wettability than titanium discs. The X-ray diffraction results showed amorphous TiO₂ phase on titanium discs, whereas TiO₂ sol-gel surfaces presented TiO₂ rutile and anatase phase. After 4 hours, the number of osteoblasts seeded on TiO₂ surface was significantly higher than those on titanium discs. The mRNA expression of bone sialoprotein and osteocalcin were also higher on day 5 and 7, respectively. Enzyme-linked immunosorbent assay(ELISA) analysis confirmed the increase of osteocalcin protein synthesis in osteoblasts grown on the TiO₂ sol-gel surface. Alizarin red-S staining showed higher amount of calcium deposition from osteoblasts cultured on TiO₂ surface than those on titanium discs at day 20. In conclusion, TiO₂ sol-gel coated-titanium could enhance osteoblasts differentiation and promote mineralization, indicating its potential in improving osseointegration for clinical application.

Deposition of Conformal Catalyst Coatings on Porous Electrodes Using a Layer-By-Layer Surface Sol-Gel Process

The state-of-the-art cathode of solid oxide fuel cells suffers from accelerated degradation and slow reaction kinetics for the oxygen reduction reaction (ORR). Surface modification of the cathode has been widely investigated and shown to greatly improve catalytic activity and prevent the formation of insulating phases. However, there is a need to improve the quality of the surface modification coatings while reducing the cost. In this presentation, we report a novel surface modification technique, coined layer-by-layer surface sol-gel (LbL SSG), for deposition of BaO and Pr2O3 on a porous La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathode, greatly increasing the catalytic activity for ORR and tolerance against contaminants. This low-cost, liquid phase deposition technique produces conformal coatings with precise thickness control by utilizing alternating self-limiting reactions between chemisorbed metal alkoxides and water on hydroxyl-rich surfaces. The availability of many different metal alkoxide precursors previously proved in traditional sol-gel processes, capability to deposit at room temperature, and lack of expensive vacuum equipment make this technique extremely promising over other conformal deposition techniques such as atomic layer deposition. LbL SSG is shown to produce much more conformal coatings throughout the entire porous cathode and further reduce degradation over similar coatings produced via solution infiltration. Electrochemical impedance spectroscopy analysis shows a great reduction in polarization resistance of symmetrical cells with electrodes modified by catalyst coatings. Utilizing the precise thickness control of the layer by layer process via deposition cycle count, the optimum thickness is determined to be about 8 nm (derived from 30 cycles). Thinner films are shown to be instable, breaking down and degrading over the first 30 hours, while thicker films increase the polarization resistance due to the lower ionic conductivity of the catalyst coatings. The process also demonstrates excellent scalability and versatility by coating larger cathodes (one inch in diameter) and depositing various oxides using different metal alkoxide precursors. Figure 1. SEM images of bare and coated porous electrodes showing the conformal BaO film deposited via LbL SSG. The polarization resistance versus time for various deposition cycle counts showing greatly improved stability for coated cells. Figure 1

Improving the Electrochemical Performance of High Power and Energy Aqueous Rechargeable Zn/MnO2 Batteries

Rechargeable aqueous zinc ion batteries (ZIBs) have many advantages such as high abundance and low cost of Zn and safer battery chemistry in aqueous ZnSO4 electrolytes. Tunnel and layer structured manganese dioxides (MnO2) are promising cathodes for ZIBs due to their high theoretical capacity (~300mAh/g), voltage (~1.4 V vs. Zn/Zn2+) and large tunnel openings facilitating fast Zn2+ insertion/removal. However, MnO2 suffers from severe capacity fading as the battery is put through extended charge-discharge cycles due to the cathode dissolution and formation of electrochemically inactive phases such as ZnMn2O4 and ZnMn3O7·xH2O.In order to address the shortcomings of MnO2 cathodes and improve their electrochemical performances in ZIB, we have investigated the effects of (1) electrolyte concentration and type, (2) sol-gel surface coating of the cathodes, and (3) the tunnel sizes of MnO2. Here, we report that electrochemical performance of 0.46 nm x 0.46 nm tunnel sized α-MnO2 can significantly be enhanced at low concentration (≤0.5 M) ZnSO4 and ZnTFSI electrolytes. Low concentration ZnSO4 and ZnTFSI electrolytes demonstrated higher discharge capacities and capacity retentions at long battery cycling tests. At 0.1 M ZnSO4, α-MnO2 delivered 62 and 103 mAh/g capacities with 0.3 A/g rate at the 1st and 100th cycles, respectively (166% retention). At a higher charge/discharge rate of 0.9 A/g, α-MnO2 delivered 85mAh/g capacity at the 500th cycle, where the retention was 167% with respect to the 1st cycle. On the other hand, the capacity retentions were below 30% and discharge capacities were below 60 mAh/g after 100 cycles in high concentration electrolytes. Detailed characterization of spent electrodes showed that low concentration electrolytes mitigate the formation of the impurity phases and suppresses cathode dissolution. Additionally, further improvements in the ZIB performance of MnO2 have been achieved in 0.5 M ZnTFSI electrolytes and MnO2 materials with larger tunnel and layer openings.

Ultrathin ZrO2-coated separators based on surface sol-gel process for advanced lithium ion batteries

Coating inorganic ceramic particles on commercial separators with organic binders attracts significant interest as a facile and effective modification method to enhance the thermal-resistance characteristics of the separators. Nevertheless, this method still suffers from some inherent limitations, involving the desquamation of binders soaked in the electrolytes and a significant thickness increase caused by ceramic coatings. Herein, we introduce self-assembled nano-thick ZrO2 ceramic coatings onto a polypropylene (PP)/polyethene (PE)/PP separator using a dopamine hydrophilic modification and a subsequent surface sol-gel process. In comparison with the pristine separator, the modified separator exhibits excellent mechanical properties, favorable electrolyte wettability, enhanced thermal-resistance characteristics, elevated ionic conductivity and smaller electrochemical impendence. At high temperature (55 °C), the LiNi0.8Co0.15Al0.05O2 (NCA)//Li coin cell based on S–10ZrO2 exhibits the highest specific capacity of 203.7 mAh g−1, which is higher than that of the NCA//Li coin cell using the PP/PE/PP separator. In addition, the reserve experiments at various high temperatures reveal that the cells with S–10ZrO2 are more stable than the others, holding 4.08 V even for 12 h of storage at a high temperature of 120 °C.