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The thermal stability of the polyethylene (PE) separator is of utmost importance for the safety of lithium-ion batteries. Although the surface coating of PE separator with oxide nanoparticles can improve thermal stability, some serious problems still exist, such as micropore blockage, easy detaching, and introduction of excessive inert substances, which negatively affects the power density, energy density, and safety performance of the battery. In this paper, TiO2 nanorods are used to modify the surface of the PE separator, and multiple analytical techniques (e.g., SEM, DSC, EIS, and LSV) are utilized to investigate the effect of coating amount on the physicochemical properties of the PE separator. The results show that the thermal stability, mechanical properties, and electrochemical properties of the PE separator can be effectively improved via surface coating with TiO2 nanorods, but the degree of improvement is not directly proportional to the coating amount due to the fact that the forces inhibiting micropore deformation (mechanical stretching or thermal contraction) are derived from the interaction of TiO2 nanorods directly "bridging" with the microporous skeleton rather than those indirectly "glued" with the microporous skeleton. Conversely, the introduction of excessive inert coating material could reduce the ionic conductivity, increase the interfacial impedance, and lower the energy density of the battery. The experimental results show that the ceramic separator with a coating amount of ~0.6 mg/cm2 TiO2 nanorods has well-balanced performances: its thermal shrinkage rate is 4.5%, the capacity retention assembled with this separator was 57.1% under 7 C/0.2 C and 82.6% after 100 cycles, respectively. This research may provide a novel approach to overcoming the common disadvantages of current surface-coated separators. [ABSTRACT FROM AUTHOR]

CaMoO 4 :Pr3+ thermochromic phosphors with diverse thermal responses for temperature sensing were prepared by the traditional solid-phase reaction method. The typical CaMoO 4 :Pr3+ had scheelite structure belonging to tetragonal crystal system and space group of I 4 1 / a (88). Pr3+ ions can be easily substituted for Ca2+ ions of host CaMoO 4 because of similar ionic radius. CaMoO 4 : 1.5% Pr3+ have the block structure with mean size of 6.84 μm. The E g (∼3.93 eV) value of pure CaMoO 4 is bigger than that (∼3.65 eV) of CaMoO 4 : 1.5%Pr3+, attributing to the existence of intermediate defect energy levels. Appropriate Pr3+ doping concentration is 1.5%, and the concentration quenching phenomenon can be explained by the concrete electric multipole type of d-d interaction. The emission peak at ∼605 nm from 1D 2 →3H 4 transition have a good thermal stability of 99.452%@423 K, while the wide band centered at ∼490 nm from 3T 1,2 → 1A 1 transition in the MoO 4 2− complex and 3P 0 →3H 4 transition in Pr3+ have a poor thermal stability of 27.572%@423 K. Calculated activation energy is 0.239 eV. Temperature-dependent FIR for optical thermometry was constructed due to their diverse thermal responses. CaMoO 4 : Pr3+ phosphor had good relative sensitivities of 2.216%, 0.969% and 0.932% based on FIR of I 605 nm /I 490 nm with Boltzmann distribution, modified Boltzmann distribution and exponential equation fitting. Thermochromic behavior and thermal quenching mechanism are investigated. The obtained relative sensitivity is better than that of most phosphors, implying that CaMoO 4 : Pr3+ has a potential for application in optical thermometry. [ABSTRACT FROM AUTHOR]

Abstract The Eu3+-doped α-Al 2 O 3 micro/nano-biscuits were prepared via microwave/starch- assisted sol-gel approach. The typical sample had the pure hexagonal α-Al 2 O 3 phase. The solubility limit of Eu3+ ions was ~ 2 mol%. The micro/nano-biscuits consisted of the outer layers paved with nanoparticles of 50–70 nm and inner layers arranged with nanoparticles of 100–200 nm in a brick-upon-tile pattern. The forming mechanism was proposed. Optical bandgap values were apparently lower than that of bulk Al 2 O 3 (~ 8.7 eV), assigned to appearance of some defect levels and incorporation of impurity ions. The critical distance was ∼ 15.95 Å and ET mechanism was the d-d interaction. The integrated strength at 423 K dropped to 68% of the original value at 298 K and the E a was ~ 0.259 eV. Moreover, the CIE coordinate of the typical sample with good thermal stability was close to that of the commercial red phosphor, having promising applications in pc-WLEDs as a red-emitting phosphor. Graphical abstract fx1 [ABSTRACT FROM AUTHOR]

SrMoO 4 : Sm3+ orange red-emitting phosphors for novel application in temperature measurement were prepared by solid-phase synthesis method. SrMoO 4 : Sm3+ phosphor with scheelite structure was assigned to tetragonal system and I 4 1 /a space group. Sm3+ ions could occupy Sr2+ lattice sites of SrMoO 4. SrMoO 4 : Sm3+ consisted of irregular microparticle with well-crystallized pomegranate seed-like morphology and Sm3+ ions can be evenly distributed in the SrMoO 4 matrix. The band gap value of SrMoO 4 : 1.0%Sm3+ (∼4.228 eV) is less than that of SrMoO 4 (∼4.267 eV), which is due to generation of defective energy levels in band gap. The appropriate quenching concentration of Sm3+ was 1.0%, the critical distance is ∼25.57 Å and θ is 7.1, close to 8, which was attributed to dipole−quadrupole interaction type of electric multipolar interaction. SrMoO 4 :1.0%Sm3+ had excellent thermal stability of the PL peak at 598 nm and 644 nm and anti-thermal quenching property of the PL peak at 530 nm and 563 nm. The activation energy based on the intensity of the PL peak at 598 nm is 0.318 eV. The new dual-model thermometry strategy base on exponential function and modified Boltzmann population distribution would be proposed. SrMoO 4 :Sm3+ phosphor had the absolute sensitivities of 0.108 K−1 based on exponential function and the relative sensitivities of 0.601% K−1 based on modified Boltzmann population distribution. The excellent anti-thermal quenching and good thermal stability of SrMoO 4 : Sm3+ phosphors indicate that it has a potential for applications as pc-WLEDs and optical thermometry. [Display omitted] • SrMoO 4 : Sm 3+ thermometric phosphors were prepared by solid state reaction method. • The excellent anti-thermal quenching and good thermal stability of SMO: Sm3+ phosphors. • The new dual-model thermometry strategy would be proposed. • SrMoO 4 : Sm3+ has a potential for application as optical thermometry. [ABSTRACT FROM AUTHOR]

A series of Sm3+ doped phosphor Sr 2 Ga 2 GeO 7 :xSm3+ (0 = x ≤ 0.05) were synthesized for the first time to obtain red emitting component for efficient WLED device with excellent electroluminescence (EL) performance. The X-ray diffraction (XRD) analysis revealed that these powders crystalized in a tetragonal with a space group of P-421m (113) and the Sm3+ occupied the positions Sr2+ ions in the lattice of Sr 2 Ga 2 GeO 7. The germanate material Sr 2 Ga 2 GeO 7 possess a broad optical energy bandgap (E g) of 5.03 eV, which was beneficial for the charge transfer of Sm3+ to the matrix. The photoluminous (PL) properties proved that these red emitting phosphors Sr 2 Ga 2 GeO 7 :xSm3+ (0 ≤ x ≤ 0.05) exhibited two emission peaks at about 563 nm and 602 nm, which originated from the 4G 5/2 → 6H 5/2 and 4G 5/2 → 6H 7/2 transitions of Sm3+ ions under 404 nm excitation. Interestingly, when the contents of Sm3+ reached 2% mol, sample Sr 2 Ga 2 GeO 7 :0.02Sm3+ possessed a relatively best PL characterize with the CIE coordinates of (0.5386, 0.4563). Based on its good PL emission stability and decay lifetime, sample Sr 2 Ga 2 GeO 7 :0.02Sm3+ showed an excellent thermal stability with the PL emission intensity only reduced by 15.02% relative to its initial PL emission intensity when measured at 473 K. As a result, the WLED device based on phosphor Sr 2 Ga 2 GeO 7 :0.02Sm3+ presented a splendid EL performance, with a low correlated color temperature (CCT) of 4252 K, a high color rendering index (R a) of 90.6 and the CIE coordinates of (0.3701, 0.3707). • Red phosphor Sr 2 Ga 2 GeO 7 :0.02Sm3+ was first synthesized. • Sample Sr 2 Ga 2 GeO 7 :0.02Sm3+ possessed high thermal stability. • The WLED device exhibited an impressive R a of 90.6 and a low CCT of 4252 K [ABSTRACT FROM AUTHOR]

Sm3+ and Pr3+ ion co-doped phosphors Ca 3 Y 2 Ge 3 O 12 :0.04Sm3+:yPr3+ (0.001 ≤ y ≤ 0.006 mol%) were synthesized by high tempereture calcination process. The XRD results showed that samples Ca 3 Y 2 Ge 3 O 12 :0.04Sm3+:yPr3+ (0.001 ≤ y ≤ 0.006) were matched well with the standard profile Ca 3 Y 2 Ge 3 O 12 (PCSD No. 27–0092) which possessed a cubic structure with the space group I a-3d (230), and these synthesized samples exhibited irregular particles with large size of about 40 μm. The photoluminescence (PL) study demonstrated that the co-doped Pr3+ ions could improve the PL properties through the energy transition (ET) process between Pr3+ ions and Sm3+ ions, leading to a smaller liftimes of Ca 3 Y 2 Ge 3 O 12 :0.04Sm3+:0.003Pr3+ than Ca 3 Y 2 Ge 3 O 12 :0.04Sm3+. The optimum Pr3+ ions doping concentration was y = 0.003 and the CIE coordinates (0.5249, 0.4730) of Ca 3 Y 2 Ge 3 O 12 :0.04Sm3+:0.003Pr3+ lied in red light region. Notably, sample Ca 3 Y 2 Ge 3 O 12 :0.04Sm3+:0.003Pr3+ exhibited better thermal stability and larger activation energy (E a) by compariton of Ca 3 Y 2 Ge 3 O 12 :0.04Sm3+. Finally, the WLED device based on Ca 3 Y 2 Ge 3 O 12 :0.04Sm3+:0.003Pr3+, (Ba, Sr) 2 SiO 4 : Eu2+ and an ultraviolet chip of 395 nm exhibited a low correlated temperature (CCT) of 3929 K and a color rendering index (R a) of 89. Image 1 • Pr3+ can improve PL properties of Ca 3 Y 2 Ge 3 O 12 :0.04Sm3+:0.003Pr3+. • Phosphor Ca 3 Y 2 Ge 3 O 12 :0.04Sm3+:0.003Pr3+ exhibited a splendid thermal stability. • Ca 3 Y 2 Ge 3 O 12 :0.04Sm3+:0.003Pr3+ based WLED exhibited a low CCT and a high R a. [ABSTRACT FROM AUTHOR]

A series of red emitting phosphors Mg 3 Y 2-x Ge 3 O 12 :xSm3+ (0≤x ≤ 0.06) were successfully synthesized. Samples Mg 3 Y 2-x Ge 3 O 12 :Sm3+ exhibited a cubic structure pertaining to the I a-3d (230) space group and the particle sizes range from 1 μm to 5 μm. The optical properties displayed that the optimum doping concentration of Sm3+ is 4%. The phosphor Mg 3 Y 1.96 Ge 3 O 12 :0.04Sm3+ not only exhibited a broad band gap of 5.54 eV but also showed a high color purity of 97.6%. In addition, the strongest emission intensity located at 566 nm belonged to the 4G 5/2 → 6H 5/2 transition when excited at 405 nm. Thermal quenching test revealed that the sample Mg 3 Y 1.96 Ge 3 O 12 :0.04Sm3+ are excellent powders with splendid thermal stability, in which only 3.6% of the PL intensity is quenched at 473 K in comparison with that of 298 K. As a result, the W-LEDs based on Mg 3 Y 1.96 Ge 3 O 12 :0.04Sm3+ yielded a high R a of 91.1, a low CCT of 4881 K, and CIE coordinates of (0.3476, 0.3466) in a 20 mA driven current. This research work provided important guidance for the synthesis of Sm3+ doped red component with excellent luminesce properties and high thermal stability characteristics used in W-LEDs. • The phosphor Mg 3 Y 1.96 Ge 3 O 12 :0.04Sm3+ not only exhibited a broad band gap of 5.54 eV but also showed a high color purity of 97.6%. • The sample Mg 3 Y 1.96 Ge 3 O 12 :0.04Sm3+ are excellent powders with splendid thermal stability. • The W-LEDs based on Mg 3 Y 1.96 Ge 3 O 12 :0.04Sm3+ exhibited an excellent electroluminesce performance in a 20 mA driven current. [ABSTRACT FROM AUTHOR]

Two series of Eu3+ ions activated high performance red-emitting phosphors Ba 2(1-x) AGe 2 O 7 : 2xEu3+ (A = Mg, Zn, 0 ≤ x ≤ 0.2) were synthesized by high-temperature solid-state procedure. The research results showed that the host lattice Ba 2 MgGe 2 O 7 possess higher band gap than that of Ba 2 ZnGe 2 O 7 , and all the Ba 2(1-x) MgGe 2 O 7 : 2xEu3+ (BMGO: 2 xEu3+, 0 ≤ x ≤ 0.2) and Ba 2(1-x) ZnGe 2 O 7 : 2xEu3+ (BZGO: 2 xEu3+, 0 ≤ x ≤ 0.2) phosphors crystallized in a tetragonal unit cell with the space group of P 421 m (113). Compared with other phosphors in the same series, the samples BMGO: 0.30 Eu3+ and BZGO: 0.25 Eu3+ presented the highest absorption intensity when monitoring at 616 nm under 395 nm excited, respectively. Moreover, the samples BMGO: 0.30 Eu3+ and BZGO: 0.25 Eu3+ not only exhibited high color purity of 90% and 90.3%, respectively, but also possess excellent thermal stability. Unsurprisingly, the WLED devices based on BMGO: 0.30 Eu3+ and BZGO: 0.25 Eu3+ as the red-emitting components displayed good luminescence properties, especially the color rendering index (CRI, R a) R 9 represented the saturation of colour of illuminated objects exhibited a high value of 89.6 and 82.3, respectively. In contrast, the WLED device based on BMGO: 0.30 Eu3+ as red-emitting phosphors presented better electroluminescence performances than those of BZGO: 0.25 Eu3+ on account of its much favorable crystal structure, PL performance and thermal stability. Image 1 • Ba 2 AGe 2 O 7 : Eu3+ were synthesized as red-emitting phosphors. • BMGO:0.3Eu3+ and BZGO:0.25Eu3+ exhibit excellent color purity and thermal stability. • BMGO:0.3Eu3+ and BZGO:0.25Eu3+ based WLED present excellent luminescence properties. [ABSTRACT FROM AUTHOR]