Binders have a great impact on the performance of lithium-ion batteries, although small doses of binder is applied. The traditional binder poly (vinylidene fluoride) cannot meet the requirements of modern lithium-ion batteries, especially those with high specific capacity, because it interacts with electrode materials through weak Van de Waals force. The surfaces of most electrode materials have polar groups which can strongly interact with polar polymeric binders. Therefore, the polar polymeric binders have been paid much attention, recently. Many factors of polar polymeric binders influence the properties of lithium-ion batteries. This review mainly focuses on the impacts of structure properties of polar polymeric binders on lithium-ion batteries, including structural feature, adhesiveness, mechanical properties, conductivity, and other properties Besides, we propose the strategies of designing next-generation binders for lithium-ion batteries from molecular level, and claim the future direction and prospects of the binders.

The carbon bonded carbon fiber network was prepared by using carbon fibers carbonized at 500 ℃ with mesophase pitch as binder. The sample was compared with the one prepared by using carbon fibers carbonized at 1300 ℃and the one prepared by using phenolic resin as the binder. The carbon yields of binders, microstructure, graphitization degree and crystallite size of samples were characterized and thermal conductivity was obtained for the samples soaked into phase change materials (PCM) to form PCM composites. Results showed that a good “in-plane” bonding effect was formed between the highly aligned graphene layers of binders and graphite fibers. The density of the carbon fiber network after graphitization is 0.317 g?cm ^-3, and the in-plane thermal conductivity of its PCM composite is 19.30 W?m ^-1?K ^-1, increased by 80-folds as hhat of pure PCMs.

The existence of impuritiy phases such as Bi₂₅FeO₃₉ and Bi₂Fe₄O₉ has led to high leakage current in BiFeO₃ multiferric materials, which consequently restricts further understanding of its coupling between magnetic and polarization orders. Prior to the attempts to synthesize pure-phase BiFeO₃ ceramics, the phase transition involved in the reaction sintering should be clarified. In the present, the phase transformations during the reaction sintering process of BiFeO₃ ceramics with different molar ratio of Bi₂O₃/Fe₂O₃ in air were studied via High Temperature X-ray Diffraction technique (HT-XRD), Rietveld refinement quantification, and High Temperature Raman Spectroscopy (HT-Raman). The thermal stabilities of BiFeO₃, Bi₂₅FeO₃₉ and Bi₂Fe₄O₉ ceramics were also studied by such methods. The qualitative phase distributions after heating were analyzed by Electron Backscattered Diffraction (EBSD). Results show that the phase transition from monoclinic to cubic for Bi₂O₃ was well done, which usually taken place at 700 ℃. The Fe₂O₃ did not react with Bi₂O₃ to form BiFeO₃ until that transition finished. In addition, BiFeO₃, Bi₂₅FeO₃₉ and Bi₂Fe₄O₉ phases are not in thermodynamic stable state during the cooling process for Bi excess samples. Bi₂O₃ excess can effectively inhibit the formation of impurities and promote the sintering of BiFeO₃ phase. The phase content of BiFeO₃ mainly depends on the molar ratio of Bi₂O₃/Fe₂O₃, and 1.03 : 1 is optimum. Combining with our previous research results, it is found that the effective parameters for the synthesis of BiFeO₃ strongly depend on the excessive Bi and rapid heating and cooling rate. This work may provide useful experimental guidance for the preparation of pure-phase BiFeO₃ ceramics.

Thermal diffusivity can be measured by the laser flash method. Previous study showed that Cu₂S has extremely low thermal diffusivity during the first-order phase transition. However, when laser is applied on the measured sample, both the absorption/emission of light and the increase of temperature on the measured sample will occur. Their effects on the measurement accuracy of the thermal diffusivity during the phase transition have not been investigated yet. In this study, it is found that the absorption/emission of light has neglectable influence on the thermal diffusivity measurement of Cu₂S. However, the increase of temperature can significantly influence the measurement results and shift the temperature when the thermal diffusivity of Cu₂S starts to decrease below the starting temperature of the phase transition determined by DSC. This can be solved by building a Cu₂S/graphite double-layer structure via using the graphite to absorb part of the laser’s energy. Furthermore, a thermal transport model is developed to extract the real thermal diffusivity from the measured thermal diffusivity of the Cu₂S/graphite double-layer structure. This work is meaningful for accurate characterization and understanding of the thermal diffusivity of phase transition materials, photosensitive materials, and heat sensitive materials.

To reveal influence of doping ions on the magnetic properties of strontium ferrite materials with magnetoplumbite configurations, we studied the stable configurations and magnetic structures of strontium ferrite with and without manganese doping. The results show that the strontium ferrite is ferrimagnetic, which is consistent with the previous reports. Comparing the GGA and GGA+U approaches, the U value exhibits a significant impact on the electronic structures and atomic magnetic moments. When 3.7 eV is adopted for U value, the system changed from a metal to a semiconductor with a spin up band gap of 1.71 eV. The total magnetic moment of the pure strontium ferrite is 40 μ_B. For the SrFe_12-xMn_xO₁₉ system, the site preference of Mn substituting Fe is investigated with x=0.5 and x=1.0. When x = 0.5, the single doping Mn atom preferentially occupies the Fe (12k) site. For x=1.0, the two Mn atoms preferentially occupy the Fe (12k) and Fe (2a) sites, respectively. Doping Mn has little impact on the lattice structure of strontium ferrite, but have a significant effect on the total magnetic moments and electronic structures. When x=0.5 and x=1.0, the band gap values for spin up electrons reduced to 0.85 and 0.49 eV, and the total magnetic moments reduced to 39 and 38 μ_B, respectively. This study may provide a theoretical foundation for future experimental studies.

Nb doped YBa₂Cu₃O_7-x(YBCO) film was fabricated by metal organic deposition (MOD) method. BYNO thin film composed of Nb element was obtained with the size ranged from 20-30 nm. It is indicated that the epitaxial and random oriented BYNO nanoparticles were coexisted in YBCO film and mainly shows random orientation. Strengthening of nanostrains can be attributed towards the stacking fault parallel to the film and the lattice distortion around the BYNO nanoparticles inside the thin film. As the random fraction of BYNO increasing, the nanostrain within nanocomposites was strengthened. The nanostrain increases the magnetic flux pinning ability of the film, thereby improving the superconducting properties of the film under high magnetic field.

Low density and amorphous SiO₂ soot body was prepared by chemical vapor deposition. Its macro deformation and micro-structure evolution rule in the sintering process were characterized by TG-DSC, SEM, TEM, XRD, mercury intrusion method, nitrogen adsorption method, and high temperature melting observation system, etc. The results indicated that SiO₂ soot body began to shrink at the sintering temperature of 1000 ℃. The macro scale soot body stopped shrinking when the sintering temperature rose to 1200 ℃, with 30% ratios shrinkage. When the sintering temperature was higher than 1200 ℃, the small particles of SiO₂ started to melt. There is a clear transition boundary between solid-phase soot body and liquid-phase glass body when the sintering temperature is higher than 1250 ℃. Meanwhile, it is interesting that the pores shape of soot body evolved gradually from connective to isolated, spherical and hole-closed. When the sintering temperature reached 1500 ℃, but the transparent silica glass is obtained without pores. More importantly, the state of SiO₂ soot body remains amorphous throughout the sintering process.

Grain refinement is an effective way to enhance mechanical property of MgO·nAl₂O₃ spinel transparent ceramics. In this study, the porous body was firstly compacted and pre-densified by spark plasma sintering using pure phase MgO·1.44Al₂O₃ ceramic powder as raw material. Then, further densification at final stage has been achieved through pressureless sintering. Finally, a fine-grained MgO·1.44Al₂O₃ spinel transparent ceramic was fabricated by hot isostatic pressing at 1500 ℃ for 5 h under 180 MPa of argon. Pressureless sintering results show that narrowing the pore size distribution and reducing the average pore size can promote the densification process dramatically. And the pore-closed ceramic with average grain size of 1.4 μm and relative density of 96.7% was obtained. The transparent ceramic shows average grain size of 1.9 μm, Vickers hardness of (13.94±0.20) GPa and Young's modulus of 289 GPa. In addition, the 2-mm-thick product also displayed excellent optical transparency with the maximum transmittance 70% in visible region and 80% in infrared region, respectively.

Zinc-aluminum spinel transparent ceramics are typical multi-functional materials with excellent optical, thermal and dielectric properties. ZnAl₂O₄-Al₂O₃ ceramics green body were fabricated through aqueous gelcasting forming technique starting from the raw materials of ZnAl₂O₄ and Al₂O₃. The stable slurries of ZnAl₂O₄-Al₂O₃ with 50vol% solids loading were prepared. Furthermore, the effects of the dispersant, pH value and solid loading on the rheological properties were systematically investigated. Then, gel-casted green compacts were pressureless sintered and hot isostatic pressed to obtain transparent ceramics. Finally, transparent ZnO·2.56Al₂O₃ ceramics (1.8 mm in thickness) with in-line transmittance value of 70% in visible region and higher than 80% in infrared region were obtained. The samples exhibited Vickers hardness of (11.34±0.17) GPa, Young's modulus of 285 GPa.

The inorganic filler is the main component of the dental restoration composite resin, which is very important for the properties and functions of composite resin. In this paper, zinc oxide (ZnO) mesocrystal microspheres were prepared from Zn(NO₃)?6H₂O solution in presence of triethanolamine as the soft template by hydrothermal method, these microspheres were self-assembled by 37.5 nm ZnO crystallite and with good order. ZnO mesocrystal microspheres were modified with γ-methacryloxypropyl trimethoxysilane (γ-MPS) and subsequently mixed with modified SiO₂ microspheres as fillers, and then added to the Bis-GMA/TEGDMA system to prepare the composite resin. Through morphology observation and performance test, it is found the filler is uniformly dispersed in composite resin. The one filled with 20wt% ZnO mesocrystals has excellent mechanical properties and wear resistance, among which the flexural strength and modulus reach 133 MPa and 9.8 GPa, respectively with the volume loss at 1.02 mm ³ after 3000 times of wearing, which was 88.7% and 90.8% lower than that of the composite resin filled with commercial ZnO microspheres and bare SiO₂, respectively. Moreover, the antibacterial rate of zinc oxide composite resin against streptococcus mutans in the oral cavity reached 99.9%.

0.94Na_1/2Bi_1/2TiO₃-0.06BaTiO₃ (NBT-6BT) perovskite structure ceramics doped by nano-sized TiO₂, which stayed in the grain boundaries of NBT-6BT grains, were prepared by the solid-state method. NBT-6BT: xTiO₂ (x=0, 0.05, 0.1, 0.2, 0.3) 0-3 type composite structure ceramics were fabricated successfully and the effects of doped TiO₂ on structure and piezoelectric properties were investigated in detail. The results show that some TiO₂ enter into the lattice of NBT-6BT matrix, which result in a decrease of Cc phase content and an enhancement of crystal symmetry. The increasing amounts of TiO₂ significantly improve the depolarization temperature of NBT-6BT ceramics. After doping 0.1 mol of TiO₂, the depolarization temperature improves by 88%. The dielectric loss tanδ and piezoelectric coefficient d₃₃ are 0.044 and 99 pC/N, respectively, which indicates that this kind of ceramic is a new type of lead-free piezoelectric materials suitable for higher temperature range.

The BaAl₂Si₂O₈-xwt%Li₂O-B₂O₃-SiO₂ (x=0, 0.1, 0.3, 0.5, 1.0, 2.0) ceramics with small amount of Li₂O-B₂O₃-SiO₂ (LBS) glass addition were prepared by solid state sintering. The sintering temperature, structure and microwave dielectric properties of BaAl₂Si₂O₈ (BAS) ceramics with xwt%LBS glass addition were investigated. The results show that the LBS glass can greatly reduce the sintering temperature, promote the growth of grain and the transformation of hexacelsian-to-celsian of BAS ceramics. As x=0.1, all the hexacelsian were transformed into celsian, and the second phase was not observed as x≤2.0. The 0.3wt%LBS glass can promote the density, dielectric constant and Q × f value increase, and the absolute value of τ_f decrease. Especially, the BAS ceramics with the 0.3wt%LBS glass addition sintered at 1275 ℃ shows a good Q × f of 34570 GHz, and the dielectric properties are ε_r = 6.74 and τ_f = -15.97 × 10 ^-6/℃.

Low energy/power density and inferior cycling stability are bottlenecks to restrict the applications of sodium-ion batteries. Recently, coating the surface of cathode material by metal oxides containing oxygen vacancies, was regarded as an effective strategy to improve electrical conductivity and power/energy density. In this study, Na₃V₂(PO₄)₂F₃@V₂O_5-x nanosheets were synthesized via hydrothermal strategy followed by heat treatment. X-ray diffraction, transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis were applied to investigate the structure of Na₃V₂(PO₄)₂F₃@V₂O_5-x. As a cathode of sodium- ion batteries, Na₃V₂(PO₄)₂F₃@V₂O_5-x delivers excellent cycling stability and rate capability. It exhibits an initial discharge capacity of 123 mAh?g ^-1 at 0.2C, and a discharge capacity of 109 mAh?g ^-1 after 140 cycles. At 1C, its initial reversible capacity is 72 mAh?g ^-1, which remains 84% after 500 cycles. The outstanding electrochemical property could be ascribed to its enhanced sodium-diffusion and improved electronic conductivity induced by disordered surface coating. Furthermore, it encourages more investigations into practical sodium-ion battery applications.

In order to improve solar thermal storage properties of the SiC_w/SiC composite ceramics, in-situ growth and morphology of SiC whiskers (SiC_w) were controlled by adding catalyst Fe₂O₃(0.5wt%-2.0wt%) on the basis of formula CF0 (SiC 69.21wt%, AlN 20.30wt%, Si 10.39wt%). Effect of Fe₂O₃ on morphology of SiC_w as well as growth mechanism and properties of SiC composite ceramics were analyzed. Results indicated that SiC_w growth mechanism changed from vapor-solid to vapor-liquid-solid after adding Fe₂O_3. The addition of Fe₂O₃ via adjusting solubility of C element into Fe-Si droplets, as well as firing temperature jointly controlled morphology of SiC_w. The sample CF4 (Fe₂O₃ 2.0wt%) fired at 1500 ℃ with whiskers diameter of 50-100 nm and 1-6 μm in length obtained optimal performance, the bulk density, bending strength, heat capacity and thermal conductivity were 2.19 g/cm ³, 45.08 MPa, 0.95 J/(g·K) (25 ℃), 18.15 W/(m·K) (25 ℃), respectively. The value of thermal conductivity increased by 169% compared to the sample without Fe₂O₃. The few defects and large-diameter of whisker grown by vapor-liquid-solid mechanism could improve thermal properties by reducing the matrix-whisker thermal barrier.

A series of Ca-substituted Sr₂Fe_1.5Mo_0.5O_6-δ oxides, Sr_2-xCa_xFe_1.5Mo_0.5O_6-δ (SCFMO, x=0, 0.2, 0.4 and 0.6), were synthesized and evaluated as potential electrodes for symmetrical solid oxide fuel cells. X-ray diffraction examination showed that all samples maintained cubic perovskite structure in both air and wet hydrogen atmospheres. Temperature programmed reduction measurements indicated that the Ca ²⁺ substitution promoted the catalytic activity of SCFMO toward oxygen evolution reactions. Symmetrical anode fuel cell measurements showed the lowest polarization resistance in humidified hydrogen emerged at x=0.6. Single cells-SC_0.6FMO|La_0.9Sr_0.1Ga_0.8Mg_0.2O₃(LSGM)|SC_0.6FMO, fabricated via tape-casting and impregnation methods, produced peak power densities of 1.05 W·cm ^-2 at 800 ℃ and 0.41 W·cm ^-2 at 650 ℃ when operating on hydrogen fuels and air oxidants. These results demonstrate SC_0.6FMO is a potential electrode material for symmetrical solid oxide fuel cells.

The nitrogen-doped porous carbon applied for oxygen reduction reaction (ORR) has aroused extensive interests due to its unique physical and chemical properties. However, the complicated nitrogen-doping strategy and high cost limit its extensive application. In this work, a series of nitrogen-doped porous carbons were prepared by a facile pyrolysis process coupling with subsequent KOH activation using renewable N-enriched biomass potato as carbon source. Effects of activation temperature and KOH amounts on the textural properties and electrocatalytic ORR activities of the final samples were investigated in detail. The KOH activation treatment results in a high specific surface area (SSA) and hierarchical porous structure, which is beneficial for improved ORR performance. The optimized NPC-750 possesses a high SSA of 1134.2 m ²?g ^-1, developed hierarchical pores as well as moderate nitrogen content (1.57at%). It also exhibits a positive onset potential of 0.89 V (vs. RHE) and half-wave potential of 0.79 V (vs. RHE). Simultaneously, the advanced long-time stability and methanol-tolerance capacity were also obtained, implying that these biomass-derived porous carbons are potential low-cost ORR electrocatalysts. Moreover, these porous carbons show great potential in various fields including supercapacitors, adsorption/separation, catalysis and batteries as well.

A modified carbothermal reduction-nitridation (CRN) method was proposed to synthesize fine AlN particles using γ-Al₂O₃ and sucrose as raw materials which were pre-treated as cellular foams. The reaction procedure and the produced AlN were investigated by XRD, SEM and TEM. XRD result suggests that γ-Al₂O₃ transferred into AlN without transformation into α-Al₂O₃. HRTEM shows that γ-Al₂O₃ particles are covered by amorphous carbon from sucrose inhibiting the transformation of α-Al₂O₃ from γ-Al₂O₃ in the synthesis procedure. The foamed structure is of benefit to the diffusion of N₂ and the produced CO. The minimum reaction temperature is 1450 ℃ for full conversion of Al₂O₃ to AlN. SEM photographs show the particle size of synthesized AlN is 50 nm. This study demonstrated an efficient way to synthesize fine AlN powders which are urgently required for the manufacture of advanced AlN ceramics.

The thermodynamic stability and thermal expansion of pure-phase BiFeO₃ multiferroic are studied using in-situ high temperature X-ray diffraction (HT-XRD), and high temperature Raman spectroscopy (HT-Raman). BiFeO₃ keeps its rhombohedral structure with space group of R3c in heating process. However, minor BiFeO₃ could decompose to Bi₂Fe₄O₉ and Bi₂₅FeO₃₉ in cooling process, which may be induced by its oxygen octahedron tilt distortion. In addition, the thermal expansion coefficients of BiFeO₃ are also investigated, showing an isotropic and positive behavior. These results are further confirmed by Raman spectrum analysis. This work may benefit for the preparation of pure-phase BiFeO₃.