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RESEARCH LETTER|55 Article(s)
Rui WU, Minhui ZHANG, Chenyun JIN, Jian LIN, and Deping WANG
Borosilicate bioglass has attracted extensive attention due to its stable structure and excellent biological activity. However, the rate of its mineralization process is fast in the initial stage and slow in the middle and late stages, which limits the application of borosilicate bioglass. As an auxiliary method, the near-infrared (NIR) laser can accelerate the degradation of bioglass. Therefore, we prepared a core-shell borosilicate bioglass with titanium nitride as the core and bioglass (40SiO2-20B2O3-36CaO-4P2O5) as the shell, and used near-infrared laser regulation technology to intervene the mineralization process of the composite bioglass. The experimental results show that the core-shell bioglass exhibits a significant photothermal effect, and the photothermal ability increases with the increases of the doping amount of TiN NPs and the laser power density. During the in vitro immersion, near-infrared laser increased the degradation rate of bioglass. After immersion for 7 d, the contents of calcium and boron in the SBF are increased by 12%-16% and 8%-11%, respectively. Meanwhile, the formation efficiency of hydroxyapatite is significantly improved. Cell proliferation activity test shows that the sample has good biological safety. Therefore, near-infrared light can accelerate the degradation and mineralization of functional core-shell bioactive glass, which is expected to play a regulatory role. Borosilicate bioglass has attracted extensive attention due to its stable structure and excellent biological activity. However, the rate of its mineralization process is fast in the initial stage and slow in the middle and late stages, which limits the application of borosilicate bioglass. As an auxiliary method, the near-infrared (NIR) laser can accelerate the degradation of bioglass. Therefore, we prepared a core-shell borosilicate bioglass with titanium nitride as the core and bioglass (40SiO2-20B2O3-36CaO-4P2O5) as the shell, and used near-infrared laser regulation technology to intervene the mineralization process of the composite bioglass. The experimental results show that the core-shell bioglass exhibits a significant photothermal effect, and the photothermal ability increases with the increases of the doping amount of TiN NPs and the laser power density. During the in vitro immersion, near-infrared laser increased the degradation rate of bioglass. After immersion for 7 d, the contents of calcium and boron in the SBF are increased by 12%-16% and 8%-11%, respectively. Meanwhile, the formation efficiency of hydroxyapatite is significantly improved. Cell proliferation activity test shows that the sample has good biological safety. Therefore, near-infrared light can accelerate the degradation and mineralization of functional core-shell bioactive glass, which is expected to play a regulatory role.
Journal of Inorganic Materials
- Publication Date: Jan. 18, 2023
- Vol. 38, Issue 6, 708 (2023)
Yingkang YANG, Yiqing SHAO, Bailiang LI, Zhiwei LÜ, Lulu WANG, Liangjun WANG, Xun CAO, Yuning WU, Rong HUANG, and Chang YANG
Wide band gap γ-CuI is a p-type transparent semiconductor with excellent optoelectronic and thermoelectric property, which has recently attracted worldwide attention. However, as an emerging material, its luminescence mechanism that is impacted by defects is rarely reported and remains obscure, limiting its further applications. In this work, Cl-doped CuI film was prepared by gas-phase reaction method. Using cathodoluminescence spectroscopy, effects of Cl doping on the surface morphology and cathodoluminescence property of CuI films were investigated in detail, and main defects of Cl presence in CuI films were explored by combining first-principle calculations, revealing relationship between structure and luminescent property of Cl-doped CuI films. These data showed Cl-doped region had a smoother surface than that of the undoped region with granular morphology, which clearly demonstrated that Cl dopant altered surface structure of the undoped region. Compared with the undoped region, the Cl dopant induced doubled fluorescence signal of band-edge emission at 410 nm, but reduced the defect peak at 720 nm, indicating that a small amount of Cl dopant brought a great luminescent improvement to CuI. The formation energy calculations of various crystal defects suggest that Cl can inhibit the formation of deep-level defects such as I vacancy in CuI and reduce the probability of non-radiative transition of excitons, which is consistent with the cathodoluminescence results. The full width at half maximum of the band-edge luminescence peak of Cl-doped CuI film is as small as 7 nm, showing extremely high luminescence monochromaticity. Therefore, the present findings deepen our understanding on how halogen doping boosts the luminescence performance of CuI-based materials. Wide band gap γ-CuI is a p-type transparent semiconductor with excellent optoelectronic and thermoelectric property, which has recently attracted worldwide attention. However, as an emerging material, its luminescence mechanism that is impacted by defects is rarely reported and remains obscure, limiting its further applications. In this work, Cl-doped CuI film was prepared by gas-phase reaction method. Using cathodoluminescence spectroscopy, effects of Cl doping on the surface morphology and cathodoluminescence property of CuI films were investigated in detail, and main defects of Cl presence in CuI films were explored by combining first-principle calculations, revealing relationship between structure and luminescent property of Cl-doped CuI films. These data showed Cl-doped region had a smoother surface than that of the undoped region with granular morphology, which clearly demonstrated that Cl dopant altered surface structure of the undoped region. Compared with the undoped region, the Cl dopant induced doubled fluorescence signal of band-edge emission at 410 nm, but reduced the defect peak at 720 nm, indicating that a small amount of Cl dopant brought a great luminescent improvement to CuI. The formation energy calculations of various crystal defects suggest that Cl can inhibit the formation of deep-level defects such as I vacancy in CuI and reduce the probability of non-radiative transition of excitons, which is consistent with the cathodoluminescence results. The full width at half maximum of the band-edge luminescence peak of Cl-doped CuI film is as small as 7 nm, showing extremely high luminescence monochromaticity. Therefore, the present findings deepen our understanding on how halogen doping boosts the luminescence performance of CuI-based materials.
Journal of Inorganic Materials
- Publication Date: Feb. 13, 2023
- Vol. 38, Issue 6, 687 (2023)
Yue LI, Xuliang ZHANG, Fangli JING, Zhanggui HU, and Yicheng WU
Besides its application as nonlinear optical devices, La2CaB10O19 (LCB) crystal has been extensively studied as a host crystal due to excellent properties. Nevertheless, rare-earth (RE) ions doped LCB crystals for ultraviolet (UV) lasers have not been studied yet. In this work, Ce3+ doped La2CaB10O19 (Ce3+:LCB) crystal with the size of 40 mm×21 mm×6 mm was grown by top-seeded solution growth (TSSG) method. Its lattice parameters are slightly different from that of the LCB crystal, and its X-ray rocking curve indicates that the Ce3+:LCB is of high crystalline quality. Transmittance spectrum and UV absorption spectrum measured at room temperature show intense absorption in the ranges of 200-288 nm and 305-330 nm,and Sellmeier equations for the refractive indices were determined by least-squares method. The excitation and fluorescence spectra show that there are two broad excitation peaks at 280 nm and 316 nm, corresponding to transitions of Ce3+ ions from 4f to 5d. Four emission peaks were obtained at 290, 304, 331, and 355 nm, which correspond to transitions from 5d state to 2F5/2 state and 2F7/2 state. Ce3+:LCB crystal exhibits high thermal conductivity (6.45 W/(m·K)) at 300 K, and keeps good thermal stability with the increase of temperatures. Its thermal expansion coefficients and lattice parameters of c direction linearly enlarge from 2.94×10-6 /K and 0.91240 nm to 5.3×10-5 /K and 0.91246 nm in the temperature range from 358 K to 773 K, respectively. These results demonstrate that Ce3+:LCB crystal has excellent optical properties and good thermal stability, which is conducive to its application for UV lasers. Besides its application as nonlinear optical devices, La2CaB10O19 (LCB) crystal has been extensively studied as a host crystal due to excellent properties. Nevertheless, rare-earth (RE) ions doped LCB crystals for ultraviolet (UV) lasers have not been studied yet. In this work, Ce3+ doped La2CaB10O19 (Ce3+:LCB) crystal with the size of 40 mm×21 mm×6 mm was grown by top-seeded solution growth (TSSG) method. Its lattice parameters are slightly different from that of the LCB crystal, and its X-ray rocking curve indicates that the Ce3+:LCB is of high crystalline quality. Transmittance spectrum and UV absorption spectrum measured at room temperature show intense absorption in the ranges of 200-288 nm and 305-330 nm,and Sellmeier equations for the refractive indices were determined by least-squares method. The excitation and fluorescence spectra show that there are two broad excitation peaks at 280 nm and 316 nm, corresponding to transitions of Ce3+ ions from 4f to 5d. Four emission peaks were obtained at 290, 304, 331, and 355 nm, which correspond to transitions from 5d state to 2F5/2 state and 2F7/2 state. Ce3+:LCB crystal exhibits high thermal conductivity (6.45 W/(m·K)) at 300 K, and keeps good thermal stability with the increase of temperatures. Its thermal expansion coefficients and lattice parameters of c direction linearly enlarge from 2.94×10-6 /K and 0.91240 nm to 5.3×10-5 /K and 0.91246 nm in the temperature range from 358 K to 773 K, respectively. These results demonstrate that Ce3+:LCB crystal has excellent optical properties and good thermal stability, which is conducive to its application for UV lasers.
Journal of Inorganic Materials
- Publication Date: Feb. 13, 2023
- Vol. 38, Issue 5, 583 (2023)
Lei WANG, Jianjun LI, Jun NING, Tianyu HU, Hongyang WANG, Zhanqun ZHANG, and Linxin WU
CoFe2O4@zeolite (CFZ) was prepared by using a co-precipitation hydrothermal method and used for synthetic dyes degradation by activating peroxymonosulfate (PMS). Comprehensive characterizations suggest that CoFe2O4 nanoparticles composing porous shell layer is uniformly covered on Na-A zeolite. The specific surface area of CFZ is 107.06 m2/g, three times that of the original zeolite. Since CFZ has a saturation magnetization of 29.0 A·m2·kg-1, it could be separated efficiently by magnetic separation. Catalytic degradation experiments indicate that the removal of methyl orange (MO) in the CFZ/PMS system is much higher than that using CFZ or PMS alone. Under the optimum condition ([MO]=50 mg/L, [PMS]=1.0 mmol/L, 0.2 g/L CFZ, pH 8 and T=25 ℃), MO removal efficiency is up to 97.1%. Effect of various factors, including pH, PMS and CFZ dosage, MO concentration and presence of coexisting anions, on the catalytic performance of CFZ is carefully studied. Reactive oxygen species quenching experiments suggest that 1O2 and O2•- play a dominant role in the degradation process. CFZ shows excellent recycling performance that the MO removal is declined by only 2.4% after 5 cycles. Catalytic degradation mechanism of the CFZ/PMS system is explored in detail. CoFe2O4@zeolite (CFZ) was prepared by using a co-precipitation hydrothermal method and used for synthetic dyes degradation by activating peroxymonosulfate (PMS). Comprehensive characterizations suggest that CoFe2O4 nanoparticles composing porous shell layer is uniformly covered on Na-A zeolite. The specific surface area of CFZ is 107.06 m2/g, three times that of the original zeolite. Since CFZ has a saturation magnetization of 29.0 A·m2·kg-1, it could be separated efficiently by magnetic separation. Catalytic degradation experiments indicate that the removal of methyl orange (MO) in the CFZ/PMS system is much higher than that using CFZ or PMS alone. Under the optimum condition ([MO]=50 mg/L, [PMS]=1.0 mmol/L, 0.2 g/L CFZ, pH 8 and T=25 ℃), MO removal efficiency is up to 97.1%. Effect of various factors, including pH, PMS and CFZ dosage, MO concentration and presence of coexisting anions, on the catalytic performance of CFZ is carefully studied. Reactive oxygen species quenching experiments suggest that 1O2 and O2•- play a dominant role in the degradation process. CFZ shows excellent recycling performance that the MO removal is declined by only 2.4% after 5 cycles. Catalytic degradation mechanism of the CFZ/PMS system is explored in detail.
Journal of Inorganic Materials
- Publication Date: Apr. 20, 2023
- Vol. 38, Issue 4, 469 (2023)
Wenlong LIU, Jin ZHAO, Juan LIU, Xiaojian MAO, Jian ZHANG, and Shiwei WANG
To solve moisture gradients in the conventional drying with controlled temperature and relative humidity, microwave heating was employed to dry wet alumina green bodies shaped by spontaneous coagulation casting. The weight loss, linear shrinkage, surface temperature, and moisture distribution of the green bodies by conventional drying (temperature: 40 ℃; humidity: 60%) and microwave drying were investigated. The time for no further weight loss and shrinkage of the body by microwave drying (power: 250 W) were respectively shortened to 1/6.8 and 1/6 of those by conventional drying. Surface temperature of the green body during the microwave drying increased firstly and then decreased with time, which was strongly correlated with the internal moisture, while the temperature in the conventional drying keeping at 40 ℃. Low-field nuclear-magnetic-resonance (NMR) imaging revealed that the moisture distribution in the green bodies dried by microwave drying was more uniform than that by conventional drying, indicating that drying stress in the former was lower than that in the latter. After sintering at 1550 ℃ for 6 h, alumina ceramics from microwave drying had a higher flexural strength with a smaller deviation than that from conventional drying. To solve moisture gradients in the conventional drying with controlled temperature and relative humidity, microwave heating was employed to dry wet alumina green bodies shaped by spontaneous coagulation casting. The weight loss, linear shrinkage, surface temperature, and moisture distribution of the green bodies by conventional drying (temperature: 40 ℃; humidity: 60%) and microwave drying were investigated. The time for no further weight loss and shrinkage of the body by microwave drying (power: 250 W) were respectively shortened to 1/6.8 and 1/6 of those by conventional drying. Surface temperature of the green body during the microwave drying increased firstly and then decreased with time, which was strongly correlated with the internal moisture, while the temperature in the conventional drying keeping at 40 ℃. Low-field nuclear-magnetic-resonance (NMR) imaging revealed that the moisture distribution in the green bodies dried by microwave drying was more uniform than that by conventional drying, indicating that drying stress in the former was lower than that in the latter. After sintering at 1550 ℃ for 6 h, alumina ceramics from microwave drying had a higher flexural strength with a smaller deviation than that from conventional drying.
Journal of Inorganic Materials
- Publication Date: Apr. 20, 2023
- Vol. 38, Issue 4, 461 (2023)
Junlin WU, Jiyang DING, Xinyou HUANG, Danyang ZHU, Dong HUANG, Zhengfa DAI, Wenqin YANG, Xingfen JIANG, Jianrong ZHOU, Zhijia SUN, and Jiang LI
The Gd2O2S:Tb scintillation ceramics is extensively used for neutron radiography and industrial non-destructive testing due to its bright green emission, high intrinsic conversion efficiency and high thermal neutron capture cross-section. However, the existence of Gd2O3 secondary phase in Gd2O2S ceramics impedes the scintillation property. In this work, The Gd2O2S:Tb precursors were synthesized in water-bath with H2SO4 and Gd2O3 as starting materials. Molar ratio of H2SO4 to Gd2O3 defined as n was adjusted to synthesize the precursors., which influence on the properties of the precursors and powders was studied. Chemical composition of the precursors changes with the increase of n, from 2Gd2O3·Gd2(SO4)3·xH2O (n<2.00) to Gd2O3·2Gd2(SO4)3·xH2O (2.25≤n≤2.75), and to Gd2(SO4)3·8H2O (n=3.00). After being calcined and reduced, all the powders form pure Gd2O2S phase. Morphology of the Gd2O2S:Tb powders is closely related to the phase composition of the precursor. Increasement of the XEL intensity shows two stages with n increase, corresponding to the phase transition of the precursor, respectively. The Gd2O2S:Tb scintillation ceramics were therefore fabricated by vacuum pre-sintering and HIP post-treatment. The ceramics were fabricated from the powders prepared with different n, achieving high relative density and XEL intensity, except the ceramics fabricated from the powders prepared with the n=2.00, 2.25, 2.50. The increase of n is beneficial to the removal of the Gd2O3 secondary phase from the Gd2O2S:Tb ceramics. This work provides a way for eliminating the secondary phase in Gd2O2S:Tb scintillation ceramics. The Gd2O2S:Tb scintillation ceramics is extensively used for neutron radiography and industrial non-destructive testing due to its bright green emission, high intrinsic conversion efficiency and high thermal neutron capture cross-section. However, the existence of Gd2O3 secondary phase in Gd2O2S ceramics impedes the scintillation property. In this work, The Gd2O2S:Tb precursors were synthesized in water-bath with H2SO4 and Gd2O3 as starting materials. Molar ratio of H2SO4 to Gd2O3 defined as n was adjusted to synthesize the precursors., which influence on the properties of the precursors and powders was studied. Chemical composition of the precursors changes with the increase of n, from 2Gd2O3·Gd2(SO4)3·xH2O (n<2.00) to Gd2O3·2Gd2(SO4)3·xH2O (2.25≤n≤2.75), and to Gd2(SO4)3·8H2O (n=3.00). After being calcined and reduced, all the powders form pure Gd2O2S phase. Morphology of the Gd2O2S:Tb powders is closely related to the phase composition of the precursor. Increasement of the XEL intensity shows two stages with n increase, corresponding to the phase transition of the precursor, respectively. The Gd2O2S:Tb scintillation ceramics were therefore fabricated by vacuum pre-sintering and HIP post-treatment. The ceramics were fabricated from the powders prepared with different n, achieving high relative density and XEL intensity, except the ceramics fabricated from the powders prepared with the n=2.00, 2.25, 2.50. The increase of n is beneficial to the removal of the Gd2O3 secondary phase from the Gd2O2S:Tb ceramics. This work provides a way for eliminating the secondary phase in Gd2O2S:Tb scintillation ceramics.
Journal of Inorganic Materials
- Publication Date: Apr. 20, 2023
- Vol. 38, Issue 4, 452 (2023)
Yanlei SHI, Niefeng SUN, Chengyan XU, Shujie WANG, Peng LIN, Chunlei MA, Senfeng XU, Wei WANG, Chunmei CHEN, Lijie FU, Huimin SHAO, Xiaolan LI, Yang WANG, and Jingkai QIN
Indium phosphide (InP) is a kind of important compound semiconductor material, now increasingly used in high frequency electronic devices and infrared optoelectronic devices. Currently, the price of InP devices is much higher than that of GaAs devices, mainly because of its low yield of single crystals and increase of epitaxy, and device process cost due to smaller wafer diameter. Increasing the diameter of InP single crystals is critical to reducing wafer and semiconductor process costs. The main difficulties in preparing large diameter InP single crystals are increasing crystal yield and reducing stress in the crystal. The vertical gradient freeze (VGF) and the liquid encapsulated Czochralski (LEC) methods are commonly used in the industry to prepare InP, while the VGF method has little success in preparing 6-inch InP crystals, and the crystals prepared by the LEC method tend to have higher stress and dislocation density. Here we reported a semi-sealed Czochralski (SSC) method to grow large diameter InP crystals. Numerical simulations were used to analyze the temperature distribution in melt, crystal, boron oxide, and atmosphere in LEC and SSC method, with emphasis on temperature field of the SSC method. As a simulation result, the temperature gradient in the crystal of SSC method is 17.4 K/cm, significantly lower thanthat of 28.7 K/cm in the LEC method. And temperature of atmosphere near the crystal shoulder in the diameter control stage of the SSC method is 504 K higher than that of the LEC method. Then the used thermal field of SSC method was optimized according to the simulation results, and 6-inch (1 inch=2.54 cm) S doped InP single crystals with low defect density and no cracks were prepared by this optimized method, which confirmed that the optimized SSC method is promising for growing large-size InP single crystals. Indium phosphide (InP) is a kind of important compound semiconductor material, now increasingly used in high frequency electronic devices and infrared optoelectronic devices. Currently, the price of InP devices is much higher than that of GaAs devices, mainly because of its low yield of single crystals and increase of epitaxy, and device process cost due to smaller wafer diameter. Increasing the diameter of InP single crystals is critical to reducing wafer and semiconductor process costs. The main difficulties in preparing large diameter InP single crystals are increasing crystal yield and reducing stress in the crystal. The vertical gradient freeze (VGF) and the liquid encapsulated Czochralski (LEC) methods are commonly used in the industry to prepare InP, while the VGF method has little success in preparing 6-inch InP crystals, and the crystals prepared by the LEC method tend to have higher stress and dislocation density. Here we reported a semi-sealed Czochralski (SSC) method to grow large diameter InP crystals. Numerical simulations were used to analyze the temperature distribution in melt, crystal, boron oxide, and atmosphere in LEC and SSC method, with emphasis on temperature field of the SSC method. As a simulation result, the temperature gradient in the crystal of SSC method is 17.4 K/cm, significantly lower thanthat of 28.7 K/cm in the LEC method. And temperature of atmosphere near the crystal shoulder in the diameter control stage of the SSC method is 504 K higher than that of the LEC method. Then the used thermal field of SSC method was optimized according to the simulation results, and 6-inch (1 inch=2.54 cm) S doped InP single crystals with low defect density and no cracks were prepared by this optimized method, which confirmed that the optimized SSC method is promising for growing large-size InP single crystals.
Journal of Inorganic Materials
- Publication Date: Jan. 17, 2023
- Vol. 38, Issue 3, 335 (2023)
Zhiqiang WANG, Ji’an WU, Kunfeng CHEN, and Dongfeng XUE
Currently, although Er3+ and Yb3+ co-doped YAG crystals are widely used in high power solid state lasers, there are still many challenges in growing large size, low defect doped YAG crystals using the Czochralski (Cz) method. In this paper, large-sized Er3+ and Yb3+ co-doped YAG bulk crystal with a diameter of 80 mm and a length of 230 mm was obtained by the fast Cz growth method. Their structure, doping concentration, optical absorption, luminescence performances, and etching defects were evaluated.According to the Raman detecting results, there is no significant variation in the peak positions and full width at half maxima (FWHM) of the Raman peaks at different locations on the wafer, indicating that the crystal structure and strain at central and edge section of thel wafer are uniformity. The etching results show that the corrosion pits are evenly distributed over the entire corrosion surfacewithout dislocation corrosion pit, which means that the crystals are highly near perfect. Strong luminescence peaks of Yb3+ and Er3+ at different wavelengths and glow discharge mass spectrometry results demonstrate the successful doping of rare earth ions in Er,Yb:YAG single crystals. This work successfully used the Cz method to grow large-sized, low-defect Er,Yb:YAG single crystals, confirming that the fast growth method is effective for doping double rare-earth ions in YAG crystals. Currently, although Er3+ and Yb3+ co-doped YAG crystals are widely used in high power solid state lasers, there are still many challenges in growing large size, low defect doped YAG crystals using the Czochralski (Cz) method. In this paper, large-sized Er3+ and Yb3+ co-doped YAG bulk crystal with a diameter of 80 mm and a length of 230 mm was obtained by the fast Cz growth method. Their structure, doping concentration, optical absorption, luminescence performances, and etching defects were evaluated.According to the Raman detecting results, there is no significant variation in the peak positions and full width at half maxima (FWHM) of the Raman peaks at different locations on the wafer, indicating that the crystal structure and strain at central and edge section of thel wafer are uniformity. The etching results show that the corrosion pits are evenly distributed over the entire corrosion surfacewithout dislocation corrosion pit, which means that the crystals are highly near perfect. Strong luminescence peaks of Yb3+ and Er3+ at different wavelengths and glow discharge mass spectrometry results demonstrate the successful doping of rare earth ions in Er,Yb:YAG single crystals. This work successfully used the Cz method to grow large-sized, low-defect Er,Yb:YAG single crystals, confirming that the fast growth method is effective for doping double rare-earth ions in YAG crystals.
Journal of Inorganic Materials
- Publication Date: Jan. 17, 2023
- Vol. 38, Issue 3, 329 (2023)
Dongliang SU, Jin CUI, Pengbo ZHAI, and Xiangxin GUO
The large volume change of silicon anode leads to rupture of the solid electrolyte interface (SEI) and the pulverization of Si electrode during charge-discharge process, which results in uncontrolled capacity loss. In this work, a strategy to regulate the SEI composition of Si/C anodes utilizing Li6.4La3Zr1.4Ta0.6O12 (LLZTO) solid electrolyte was proposed. LLZTO layer is uniformly coated on the surface of polypropylene (PP) separator, which not only improves wettability of the electrolyte to the separator, thereby homogenizing the lithium-ion flux, but also increases the proportion of inorganic components in SEI and enhances the interfacial stability of Si/C anodes. As a result, Li batteries using the LLZTO coated PP separator exhibit better cycling stability and rate capability. Li-Si/C half cell exhibits a reversible capacity of 876 mAh·g-1 with 81% capacity retention for more than 200 cycles at 0.3C (1C= 1.5 A·g-1), and Si/C-LiFePO4 (LFP) full cell delivers a capacity of 125 mAh·g-1 with 91.8% capacity retention after 100 cycles at 0.3C (1C=170 mA·g-1). This work reveals the mechanism of LLZTO solid electrolytes in regulating the SEI of Si/C anodes and sparks new ideas for developing high-performance silicon-based lithium batteries. The large volume change of silicon anode leads to rupture of the solid electrolyte interface (SEI) and the pulverization of Si electrode during charge-discharge process, which results in uncontrolled capacity loss. In this work, a strategy to regulate the SEI composition of Si/C anodes utilizing Li6.4La3Zr1.4Ta0.6O12 (LLZTO) solid electrolyte was proposed. LLZTO layer is uniformly coated on the surface of polypropylene (PP) separator, which not only improves wettability of the electrolyte to the separator, thereby homogenizing the lithium-ion flux, but also increases the proportion of inorganic components in SEI and enhances the interfacial stability of Si/C anodes. As a result, Li batteries using the LLZTO coated PP separator exhibit better cycling stability and rate capability. Li-Si/C half cell exhibits a reversible capacity of 876 mAh·g-1 with 81% capacity retention for more than 200 cycles at 0.3C (1C= 1.5 A·g-1), and Si/C-LiFePO4 (LFP) full cell delivers a capacity of 125 mAh·g-1 with 91.8% capacity retention after 100 cycles at 0.3C (1C=170 mA·g-1). This work reveals the mechanism of LLZTO solid electrolytes in regulating the SEI of Si/C anodes and sparks new ideas for developing high-performance silicon-based lithium batteries.
Journal of Inorganic Materials
- Publication Date: Jul. 20, 2022
- Vol. 37, Issue 7, 802 (2022)
Huikai HE, Rui YANG, Jian XIA, Tingze WANG, Dequan DONG, and Xiangshui MIAO
Two-dimensional transition metal dichalcogenides are appealing materials for the preparation of nanoelectronic devices, and the development of memristors for information storage and neuromorphic computing using such materials is of particular interest. However, memristor arrays based on two-dimensional transition metal dichalcogenides are rarely reported due to low yield and high device-to-device variability. Herein, the 2D MoTe2 film was prepared by the chemical vapor deposition method. Then the memristive devices based on 2D MoTe2 film were fabricated through the polymethyl methacrylate transfer method and the lift-off process. The as-prepared MoTe2 devices perform stable bipolar resistive switching, including superior retention characteristics (>500 s), fast switching (~60 ns for SET and ~280 ns for RESET), and excellent endurance (>2000 cycles). More importantly, the MoTe2 devices exhibit high yield (96%), low cycle-to-cycle variability (6.6% for SET and 5.2% for RESET), and low device-to-device variability (19.9% for SET and 15.6% for RESET). In addition, a 3×3 memristor array with 1R scheme is successfully demonstrated based on 2D MoTe2 film. And, high recognition accuracy (91.3%) is realized by simulation in the artificial neural network with the MoTe2 devices working as synapses. It is found that the formation/rupture of metallic filaments is the dominating switching mechanism based on the investigations of the electron transport characteristics of high and low resistance states in the present MoTe2 devices. This work demonstrates that large-scale two-dimensional transition metal dichalcogenides film is of great potential for future applications in neuromorphic computing. Two-dimensional transition metal dichalcogenides are appealing materials for the preparation of nanoelectronic devices, and the development of memristors for information storage and neuromorphic computing using such materials is of particular interest. However, memristor arrays based on two-dimensional transition metal dichalcogenides are rarely reported due to low yield and high device-to-device variability. Herein, the 2D MoTe2 film was prepared by the chemical vapor deposition method. Then the memristive devices based on 2D MoTe2 film were fabricated through the polymethyl methacrylate transfer method and the lift-off process. The as-prepared MoTe2 devices perform stable bipolar resistive switching, including superior retention characteristics (>500 s), fast switching (~60 ns for SET and ~280 ns for RESET), and excellent endurance (>2000 cycles). More importantly, the MoTe2 devices exhibit high yield (96%), low cycle-to-cycle variability (6.6% for SET and 5.2% for RESET), and low device-to-device variability (19.9% for SET and 15.6% for RESET). In addition, a 3×3 memristor array with 1R scheme is successfully demonstrated based on 2D MoTe2 film. And, high recognition accuracy (91.3%) is realized by simulation in the artificial neural network with the MoTe2 devices working as synapses. It is found that the formation/rupture of metallic filaments is the dominating switching mechanism based on the investigations of the electron transport characteristics of high and low resistance states in the present MoTe2 devices. This work demonstrates that large-scale two-dimensional transition metal dichalcogenides film is of great potential for future applications in neuromorphic computing.
Journal of Inorganic Materials
- Publication Date: Jul. 20, 2022
- Vol. 37, Issue 7, 795 (2022)
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