MATERIALS CHEMISTRY AND PHYSICS
·
2022
·
IF 4.778
Juguo Dai,Lili Luo,Xiaohong Wang,Long Xia,Hongmei Xie,Chunying Yang,Ruipan Wang,Yiting Xu,Lizong Dai
Nowadays, energy conversion devices have gradually gained attention while vigorously developing clean energy. Carbon materials are promising candidates for supercapacitors , but two issues have plagued the researchers. 1) Does the cation radius in the neutral electrolyte significantly impact the electrochemical performance of carbon materials? 2) How to introduce heteroatoms while constructing hollow structures in carbon spheres. This work proposes a facile template free strategy that uses aniline and pyrrole as nitrogen sources to synthesize carbon sphere precursors. High-temperature carbonization combined with alkali treatment leads to the formation of N-doped hollow porous carbon spheres. Robust wall structure (thickness is about 60–80 nm) and ideal surface structure (the specific surface area is 1079.9 m 2 g −1 ) endow the carbon spheres with excellent electrochemical performance and outstanding cycle stability. The specific capacitance of the carbon spheres in Li 2 SO 4 and Na 2 SO 4 electrolytes under negative working potential (−0.8–0 V) are 378.4 and 367.6 F g −1 , respectively, at a current density of 1 A g −1 . After 5000 cycles, the capacitance retentions are 87.1% and 94.8% in Li 2 SO 4 and Na 2 SO 4 electrolytes. We inferred that the cation radius has a negligible effect on the specific capacitance of carbon materials, but has a more significant effect on the cycling stability and capacitance rate performance. It is hoped that this work can provide a reference for the subsequent construction of N-doped hollow carbon spheres and reasonable selection of electrolytes.
研究领域:
材料科学
·
电化学
·
纳米能源
·
功能材料
·
储能技术
✓ 已验证
DOI
高影响因子
MATERIALS RESEARCH BULLETIN
·
2018
·
IF 2.873
Wenjie Lin,Weiliang Wu,Jie Bao,Zongtao Liu,Kaifu Qiu,Lun Cai,Zhirong Yao,Youjun Deng,Zongcun Liang,Hui Shen
The dopant-free back contact solar cells are demonstrated based on hole selective contact material, chromium trioxide (CrO x , x < 3) with a low melting point for high stability and high performance. In this contribution, CrO x is first applied in silicon based solar cell as the emitter. Integrating 5 nm CrO x and 2 nm LiF x into solar cell as the emitter and the back surface filed, resulted in a device efficiency of 13.6%. For further improvement, the back contact solar cell reaching an efficiency of 15.8% was fabricated, by implementing the multilayer films of CrO x (5 nm)/Au (4 nm)/ CrO x (5 nm) as the emitter. The formation of Cr(OH) 3 in ambient condition, resulted in a lower work function (4.8 eV) of the CrO x film. Furthermore, the multilayer back contact solar cell demonstrated a high stability due to CrO x covered with 500 nm Ag, when stored in ambient air longer than 170 days.
研究领域:
材料科学
·
光伏技术
·
半导体器件
·
表面工程
·
能源材料
✓ 已验证
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2024
·
IF 3.3
Yaping You,Ya Zheng,Zesheng Pan,Yunluo Wang,Tianrui Zhou,Minghui Wang,Haijie Chen,Wan Jiang,Lianjun Wang
White light-emitting diode (WLED) has been widely used as solid-state lighting in recent years, with the advantages of energy saving, high luminous efficiency , and safety. Red phosphors are crucial to the color rendering index of WLED, and Eu 3+ -activated red phosphors can significantly improve the chromaticity performance of WLED. In this work, a series of new orange-red emitting BaLiZn 3 (PO 4 ) 3 : Eu 3+ phosphors were synthesized through high-temperature solid-state reaction method. The phase composition , crystal structure, morphology and photoluminescence properties of BaLiZn 3 (PO 4 ) 3 : Eu 3+ samples were investigated. The phosphors can be effectively excited by the violet light at 394 nm and emit orange-red lights corresponding to the electric dipole transition (5D 0 →7F 1 ) at 594 nm. The optimal doping concentration of Eu 3+ ions was about 5 mol%. The concentration quenching was caused by the electric dipole-dipole interaction between Eu 3+ ions. Temperature-dependent PL spectra indicate that BaLiZn 3 (PO 4 ) 3 : Eu 3+ has excellent emission and color stability at high temperatures. The color coordinates were calculated and fall in the orange-red luminescent area. The color purity is about 98.3 %, and the correlated color temperature is 1710K. These results indicate that the new orange-red phosphor BaLiZn 3 (PO 4 ) 3 : Eu 3+ has potential application prospects in WLED.
研究领域:
材料科学
·
发光材料
·
固体照明
·
无机化学
·
光电子学
✓ 已验证
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2020
·
IF 3.28
Zhiqin Zheng,Peizhang Xie,Panpan Yi,Jun Zhao,Lihong Liu,Facheng Yi
Nowadays, ultraviolet (UV) and blue converted phosphors have played a key role in the solid-state lighting field, and the white light is usually produced by mixing multiple phosphors. In this work, we report a type of UV converted single white phosphor, i.e. , Ba 9 La 2 Si 6 O 24 :Eu 3+ ,Bi 3+ .Various techniques, such as powder X-ray diffraction (XRD), scanning electron microscopic (SEM), photoluminescence (PL) spectra, and quantum efficiency (QE), have been used to characterize the samples. In Bi 3+ doped samples, upon excitation within the wavelength range of 250–380 nm can lead to three Bi 3+ emission bands ( i.e. , 358 nm, 415 nm, and 516 nm), but only one emission band peaking at 415 nm appears when the excitation wavelength exceeds 380 nm. Structural analysis and discussion on the PL intensity variation reveal there are three Bi 3+ luminescent centers at two different La 3+ sites and one Ba 2+ site. The Bi 3+ concentration-induced luminescent quenching is dominated by the d-d interaction. In view of the spectral overlap between the Bi 3+ emissions and the Eu 3+ excitation spectra , the energy transfer from Bi 3+ to Eu 3+ of the Ba 9 La 2 Si 6 O 24 :Eu 3+ ,Bi 3+ is studied, and it is dominated by a dipole-quadrupole ( d - q ) interaction. Moreover, upon excitation at 365 nm, the emissions broadly tuning from blue, white and to red are achieved by varying the Eu 3+ content. For the white Ba 9 La 2 Si 6 O 24 :Eu 3+ ,Bi 3+ sample, high temperature PL results show that it does not have severe degradation of emission intensity after increasing the temperature from 25 to 300 °C, exhibiting a good thermal stability . To show the potential application in the lighting fields, we fabricate a white light LEDs device by depositing this white phosphor on a 365 nm UV LED chip. As a result, the values, i.e. , a color rendering index (CRI) of 95, luminous efficiency of 80 lm/W, and color temperature (CT) of ~4215 K at chromaticity (0.382, 0.398), are achieved.
研究领域:
材料科学
·
发光材料
·
固态照明
·
无机化学
·
光电子学
✓ 已验证
DOI
高影响因子
POLYMER
·
2018
·
IF 3.483
Jianting Zhang,Yanhong Cui,Xiaoqing Li,Hanqiang Yao,Deming Zhao,Ningren Jin,Jianrong Gao
A novel poly(hydroxy-p-phenylenebenzobisoxazole) (HPBO) with superior comprehensive properties was synthesized via self-polymerization of composite salt monomer (HD). The molecular simulation results of relative total energies and the activation energies indicated that the meta-carboxyl group was the active site of condensation reaction which was carried out by amidation . Further molecular simulation results showed that the most probable configuration of HPBO was ordered P1 conformation, and the conjugation and stability of HPBO were enhanced by increasing the number of repeat units. The introduction of mono-hydroxyl group contributes to the formation of intramolecular hydrogen bonds of HPBO molecules, which made HPBO exhibit the molecular structure of the two-dimensional conjugate & coplanar and improved the thermal stability relative to PBO and DHPBO. The simulation results were verified by corresponding experimental investigation.
研究领域:
高分子化学
·
材料科学
·
计算化学
·
物理化学
·
功能材料
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2019
·
IF 5.383
Aijia Wei,Wen Li,Qian Chang,Xue Bai,Rui He,Lihui Zhang,Zhenfa Liu,Yanji Wang
Mg 2+ /F − co-doped LiNi 0.5 Mn 1.5 O 4 cathode material was synthesized by a facile one-step solid-state process. The effect of Mg 2+ /F − co-doping on grain morphology, phase structure, and electrochemical properties was studied by a series of characterizations. Scanning-electron-microscopy images show that Mg 2+ /F − co-doped LiNi 0.5 Mn 1.5 O 4 (denoted LNMO-MF) particles grow larger than pure LiNi 0.5 Mn 1.5 O 4 particles. X-ray diffraction, Raman spectra , Fourier transformation infrared spectroscopy , X-ray photoelectron spectroscopy, and cyclic-voltammetry tests indicate that all samples mainly display a Fd -3m space group and more Mn 3+ ions in the LNMO-MF sample after Mg 2+ /F − co-doping, which is conducive to increasing the cationic disorder degree and enhancing the electronic conductivity of electrode material. Results show that the LNMO-MF cathode material delivers an excellent rate performance with discharge capacities of 142, 144, 140 136, 132, 124, 115, and 100 mAh g −1 at 0.2, 0.5, 1, 2, 3, 5, 7, and 10C (1C = 140 mAh g −1 ), respectively. Remarkably, LNMO-MF also shows cycling stability with a capacity retention of 86.2% at 5C after 400 cycles, which is much higher than that of pure LiNi 0.5 Mn 1.5 O 4 (67.7%). The improvement of LNMO-MF's electrochemical properties could be ascribed to the Mg 2+ /F − co-doping, delivering a more stable structure, better crystallinity , the highest Li + diffusion coefficient , and the lowest charge-transfer resistance.
研究领域:
材料科学
·
电化学
·
无机非金属材料
·
能源存储
·
锂离子电池
·
固态化学
·
功能材料
✓ 已验证
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 117
·96862-96869
·
IF 3.84
Zhijie Gong,Qixing Wu,Fang Wang,Xu Li,Xianping Fan,Hui Yang,Zhongkuan Luo
Increasing the sulfur loading in the cathode of a lithium–sulfur battery is an important way to improve its capacity for practical applications. To achieve this, the present work proposes using PEDOT-PSS to encapsulate sulfur/carbon black (S/BP) by a facile solution mixing method and the formed composite is then coated on a porous carbon paper. It is believed that the formation of a core/shell structure in the PEDOT@S/BP composite can promote the electron transport and effectively impede the diffusion of polysulfides, and the porous carbon paper is able to retain the electrolyte containing the dissolved polysulfides in the cathode and alleviate the adverse effect of sulfur volumetric expansion. Due to such advantages, the proposed cathode, with a high sulfur loading of 3 mg cm−2, can yield a high reversible capacity of 1041 mA h g−1 and an excellent cycle stability with a capacity retention of 868 mA h g−1 after 100 cycles and an average coulombic efficiency of 99.4%.
研究领域:
电化学
·
能源材料
·
纳米复合材料
·
电池技术
·
功能高分子材料
✓ 已验证
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2019
·
IF 2.781
Yunjiao Li,Shilei Wang,Yongxiang Chen,Tongxing Lei,Shiyi Deng,Jie Zhu,Jinping Zhang,Jia Guo
Cadmium oxides (CdO), an important semiconductor material , have many superior properties when used as a cathode material for nickel-cadmium batteries. Here, the coating and the doped co-modified LiNi 0.8 Co 0.15 Al 0.05 O 2 cathode are constructed by a continuous wet chemical process and a high-temperature sintering process, wherein the Cd 2+ are uniformly doped in a gradient form and the CdO protective layer is distributed on the outer surface of secondary particles. The Cd-modified NCA material has more stable interfacial and crystal lattice structure, thereby inhibiting harmful phase transitions and side-reactions. Accordingly, the modified sample has excellent electrochemical performance and maintaining a complete spherical morphology during long cycling compared to the pristine sample. In addition, as a pillar ion, cadmium increases the plate spacing and lithium-ion diffusion kinetics. The electrochemical results show that the capacity retention of the modified sample Cd-2000 reached 96.5% and 90.6% after 100 cycles and 200 cycles respectively at 1 C. At the high current rate of 8 C, the initial capacity and retention (100 cycles, 3.0–4.3 V) reach 166.2 mAh g −1 and 95.2%, respectively. Besides, the results of electrochemical impedance spectroscopy (EIS) reveal that CdO modification could decrease the resistance of the cell polarization and impedance increment upon cycling.
研究领域:
材料科学
·
电化学
·
能源存储
·
无机化学
·
半导体材料
✓ 已验证
DOI
高影响因子
Laser & Photonics Reviews
·
2023
·Vol. 18
·期 1
·2300732
·
IF 11
Zhuowei Li,Ge Zhu,Shanshan Li,Wen Xu,Qingfeng Bian,Yan Cong,Ming He,Xixian Luo,Shuangyu Xin,Bin Dong
The burgeoning phosphor-converted near-infrared light-emitting diodes (pc-NIR LEDs) have important applications in special illumination and spectroscopy analysis. However, the development of efficient NIR-emitting phosphors with high performance is still a challenge. In this work, a chemical unit co-substitution strategy is proposed to realize the excitation transition regulation and successfully achieve high-performance NIR luminescence in Ca 3- y Na y Mg 1- y Sb 2- x Al 2+ y O 12 : x Cr 3+ (0 ≤ x ≤ 0.05, 0 ≤ y ≤ 1) garnet-type solid solution phosphors. Through the excitation transition modulation from the 4 A 2 ground state to the 4 T 1 ( 4 P) and 4 T 1 ( 4 F) excitation state, the excitation intensity at the blue light region is largely enhanced by 25.6 times. Moreover, the NIR-emitting efficiency and thermal stability are improved, with the optimal luminescence internal quantum efficiency of 90.6% and thermal stability of 97%@423 K, without any flux-assisted sintering or reduction atmosphere protection. The structure regulation induced small Stokes shift, weak electron-phonon coupling effect, and decreased non-radiative transition are responsible for the excellent NIR-emitting performance. Finally, the NIR pc-LED is fabricated with photoelectric efficiencies of 18.7%@100 mA and NIR output powers of 63 mW@100 mA, presenting potential applications in nondestructive internal defect detection, veins imaging, and night vision surveillance.
研究领域:
材料科学
·
光学工程
·
固体化学
·
发光材料
·
半导体器件
✓ 已验证
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 16
·13418-13425
·
IF 3.289
Fubin Luo,Kun Wu,Mangeng Lu
The influence of polybenzoxazine modified ammonium polyphosphate (BMAPP) on the thermal behavior and flame retardancy of a rigid polyurethane foam (PU) are investigated via thermogravimetric analysis (TG), TG coupled with infrared spectroscopy (TG-FTIR), UL-94 vertical burning testing and limit oxygen index (LOI). The TG testing results indicate that BMAPP can enhance the thermal stability of PU, both under air and nitrogen conditions. The initial degradation temperature of the BMAPP/PU composites is 264 °C in air, which is 22 °C and 30 °C higher than that of ammonium polyphosphate (APP)/PU composites and neat PU, respectively. The reason might be attributed to the better dispersion and compatibility of BMAPP particles in PU compared with APP, which can prevent the PU chain from degrading at low temperatures. The LOI value results demonstrate that BMAPP has higher flame retardancy in PU than APP. Residue analysis implies that polybenzoxazine is partially converted into Si–O as char residue during combustion.
研究领域:
高分子材料科学
·
阻燃材料
·
热功能材料
·
复合材料学
·
材料化学
✓ 已验证
DOI
高影响因子
Energy & Environmental Materials
·
2023
·Vol. 7
·期 3
·e12641
·
IF 15
Huachao Yang,Yiheng Qi,Zifan Wang,Qinghu Pan,Chuanzhi Zhang,Jianhua Yan,Kefa Cen,Zheng Bo,Kostya (Ken) Ostrikov
Safe operation of electrochemical capacitors (supercapacitors) is hindered by the flammability of commercial organic electrolytes. Non-flammable Water-in-Salt (WIS) electrolytes are promising alternatives; however, they are plagued by the limited operation voltage window (typically ≤2.3 V) and inherent corrosion of current collectors. Herein, a novel deep eutectic solvent (DES)-based electrolyte which uses formamide (FMD) as hydrogen-bond donor and sodium nitrate (NaNO 3 ) as hydrogen-bond acceptor is demonstrated. The electrolyte exhibits the wide electrochemical stability window (3.14 V), high electrical conductivity (14.01 mS cm −1 ), good flame-retardance, anticorrosive property, and ultralow cost (7% of the commercial electrolyte and 2% of WIS). Raman spectroscopy and Density Functional Theory calculations reveal that the hydrogen bonds between the FMD molecules and NO 3 − ions are primarily responsible for the superior stability and conductivity. The developed NaNO 3 /FMD-based coin cell supercapacitor is among the best-performing state-of-art DES and WIS devices, evidenced by the high voltage window (2.6 V), outstanding energy and power densities (22.77 Wh kg −1 at 630 W kg −1 and 17.37 kW kg −1 at 12.55 Wh kg −1 ), ultralong cyclic stability (86% after 30 000 cycles), and negligible current collector corrosion. The NaNO 3 /FMD industry adoption potential is demonstrated by fabricating 100 F pouch cell supercapacitors using commercial aluminum current collectors.
研究领域:
电化学
·
材料科学
·
能源存储
·
应用化学
·
物理化学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2019
·
IF 4.784
Quan-Yong Cheng,Xiao-Li Zhao,Yi-Dong Li,Yun-Xuan Weng,Jian-Bing Zeng
Traditional superhydrophobic cotton fabrics (SCFs) for oil/water separation were usually fabricated by surface coating with inorganic nanoparticles combined with nonrenewable and nonbiodegradable or even toxic fossil-based chemicals, which would lead to secondary environmental pollution after their lifetime. In this study, we report robust, nanoparticle-free, fluorine-free SFC, which was prepared by acid etching followed by surface coating with epoxidized soybean oil resin (CESO) and subsequent modification with stearic acid (STA). No toxic compound and no nanoparticle were included within the SCF and all the raw materials including cotton fabric, CESO and STA are biodegradable and derived from biological resources. The SCF showed excellent mechanical stability and chemical/environmental resistances. The superhydrophobicity of the SFC survived from mechanical abrasion , tape peeling, ultrasonication , solvent erosion and low/high temperature exposure. The SCF also exhibited good acid/alkali resistance with contact angle over 150° toward different pH water droplets. Moreover, the SCF could efficiently separate oil/water mixtures with efficiency above 97.9% and the superhydrophobicity remained after reusing for at least 10 times. The fully biological-derived SCF with excellent mechanical and chemical resistances exhibit great potential for separation of oil/water mixtures.
研究领域:
材料科学
·
环境工程
·
高分子化学
·
表面科学
·
可持续技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）