JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Xianqiang Chen,Binfeng Zhao,Naichao Chen,Jin Cheng,Mingzhao Dang,Feng Wang,Xinwei Xu,Hong Wang
Low-temperature-fired microwave ceramics are key to realizing the integration and miniaturization of microwave devices. In this study, a facile wet chemical method was applied to synthesize homogenous nano-sized CaF 2 powders for simultaneously achieving low-temperature sintering and superior microwave dielectric properties . Pure CaF 2 ceramics sintered at 950 °C for 6 h with good microwave dielectric properties (ε r = 6.22, Q×f = 36,655 GHz, and τ f = −102 ppm/°C) was achieved. The microwave dielectric properties of the CaF 2 ceramics were further improved by introducing LiF as a sintering aid. The sintering temperature of CaF 2 -based ceramics was effectively lowered from 950 °C to 750 °C with 10 wt% LiF doping, and excellent microwave dielectric properties (ε r = 6.37, Q×f = 65,455 GHz, and τ f = −71 ppm/°C) were obtained.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
Energy Technology
·
2025
·
IF 3.6
Anping Tang,Zhixing Sui,Liping Ning
Lithium fluoride-transition metal oxide (LiF–TMO) composites have become an attractive alternative to the traditional intercalation-type cathodes due to their high specific capacity. However, current preparation methods of these composites are not suitable for large-scale production. Therefore, it is necessary to seek new methods for preparing these composites. In the present study, LiF–MnO composites are successfully prepared by a novel solid-state reaction method using polytetrafluoroethylene as a fluorinating agent. The X-ray diffraction patterns of the samples show that LiF–MnO composites without other fluoride impurities can be achieved by optimizing sintering temperature, sintering time, and the Poly(tetrafluoroethylene) contents in the precursor. In the voltage range of 1.5–4.8 V at C/20 rate, the composite delivers a first discharge specific capacity of 180 mAh g −1 and exhibits a fairly stable cycle life.
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产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2024
·
IF 10.7
Minghui Li,Cai Chen,Hongze Luo,Qingshuai Xu,Keyou Yan,Yongcai Qiu,Guangmin Zhou
Li metal anodes are considered among the most ideal candidates for next generation batteries owing to their lowest electrochemical potential and high theoretical capacity. However, the highly reactive Li metal is subject to continuous side reactions with conventional carbonate electrolytes. The resulting unsatisfying solid electrolyte interface (SEI) induces severe Li dendritic growth. Therefore, there is an urgent need to effectively control the components of SEI to solve the electrolyte/anode interface electrochemical instability. Herein, LiDFP and LiNO3 are introduced into the electrolyte to modulate the composition of the SEI. Owing to the lower lowest unoccupied molecular orbital (LUMO) energy levels of LiDFP and LiNO3 relative to those of the solvents, LiDFP and LiNO3 have preferential reducibility and thus generate a stable SEI containing LiF and Li3N, which has swift ion migration kinetics and homogeneous Li deposition behaviors. As a result, our electrolyte modified by additives enables the anode to achieve an excellent coulombic efficiency of 98% and exhibits an ultra-long cycling life of over 700 h in symmetrical cells. Li metal full cells paired with the LFP or NCM811 cathode also have excellent long cycling performance. This work demonstrates that additive-modified electrolytes are a viable and simple strategy for the evolution of Li metal batteries.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
NATURE
·
2025
·Vol. 646
·期 8083
·102-107
·
IF 48.5
Liu Xiangsi,Li Shuyang,Yuan Chen,Zheng Bizhu,Cheng Gangya,Chen Yufan,Lu Xingyu,Gu Danyu,Lv Baijiang,Li Hao,Yan Zihan,Qian Hui,Zhu Yizhou,Sun Dalin,Song Yun,Xiang Yuxuan
The electrolyte–electrode interface serves as the foundation for a myriad of chemical and physical processes. In battery chemistry, the formation of a well-known solid–electrolyte interphase (SEI) plays a pivotal role in ensuring the reversible operations of rechargeable lithium-ion batteries (LIBs) 1 , 2 . However, characterizing the precise chemical composition of the low crystallinity and highly sensitive SEI presents a formidable challenge 3 . Here, taking lithium fluoride (LiF)—a widely studied and considered crucial SEI component 4 , 5 , 6 , 7 —as an example, we use 19 F solid-state nuclear magnetic resonance (NMR) and identify that LiF formed in SEI (LiF SEI ) has fruitful spectroscopy features that originated from the formation of limited LiF–LiH solid solutions: H-rich phase (LiH 1 − y F y ) and F-rich phase (LiF 1 − x H x ), which is further validated by 6 Li isotope NMR, synchrotron X-ray diffraction and cryo-electron microscopy (cryo-EM). By characterizing SEI formed in various electrolytes, we confirm the dominance of LiH 1 − y F y in high-coulombic-efficiency electrolyte, which can be rationalized by the fact that LiF–LiH solid solution shows improved ionic conductivity over LiF. As a proof of concept, we demonstrate that LiH 1− y F y -rich coating layer presents obvious advantages compared with LiF-rich coating layer in lithium-metal batteries. This revised understanding of the heterogeneous nature of SEI components would provide new insights for electrode–electrolyte interface design.
研究领域:
电化学
·
材料科学
·
能源化学
·
固体化学
·
电池技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2016
·
IF 1.835
Zhongning Shi,Wentao Deng,Xiaowen Song,Xianwei Hu,Bingliang Gao,Zhaowen Wang
The solubility of carbon dioxide in a LiF–Li2CO3 molten salt system was determined using a pressure differential method. With increasing holding temperature, the solubility of CO2 in LiF–Li2CO3 melts decreases rapidly. The influence of the alkali metal fluoride of XF(X = K, Na) content from 5% to 25% on the CO2 solubility was considered. The CO2 solubility in LiF–Li2CO3–XF melts decreased with increasing temperature and concentration of XF. The calculated thermodynamic data for CO2 dissolved in these melts revealed that the reaction between CO2 and a carbonate ion was exothermic. At 630 °C, KF decreased the CO2 solubility more effectively than NaF. When the mole fraction of LiF was 50% in LiF–Li2CO3, the CO2 solubility reached a maximum of 6.8 × 10–4 (molCO2/molmelt) at 640 °C.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
SCRIPTA MATERIALIA
·
2019
·
IF 4.539
Nan Lu,Gang He,Zengchao Yang,Yong Li,Jiangtao Li
MgO/Graphene composites were prepared by combustion synthesis (CS) followed with spark plasma sintering (SPS) using LiF as sintering additive. The densification mechanism of MgO/Graphene composites doped with LiF was systematically investigated. With incorporating small amount of graphene into MgO , the spectral absorptivity of the composite was improved, whereas the density, hardness and average grain size were decreased. The densification of submicron sized MgO/Graphene ceramics was realized by the balance between sintering promoted by LiF and grain refinement of graphene.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2017
·Vol. 28
·期 19
·14901-14905
·
IF 2.019
Cheng L.,Pan H. L.,Li M. F.,Ling F.,Wu H. T.
Li 2 Mg 3 ZrO 6 (LMZ) ceramics doped with 1–5 wt% LiF were prepared by the conventional solid-state reaction method. The influences of LiF addition on the phase compositions, micro-structure, sintering behavior and microwave dielectric properties of LMZ ceramics were explored. A small quantity of LiF addition could obviously reduce the sintering temperature to 950 °C while maintaining the excellent dielectric properties. The optimized quality factor values for different doping components firstly increased and then decreased with the increase of the LiF content, whereas the optimized dielectric permittivity increased with the increase of the LiF content. LMZ ceramics sintered at 950 °C doped with 4 wt% LiF additives possessed the excellent microwave dielectric properties of ε
r
= 12.66, Q · f = 89,325 GHz and τ
f
= −14.46 ppm/°C, which demonstrated that the materials were promising for the low temperature co-fired ceramics applications.
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DOI
高影响因子
MATERIALS RESEARCH BULLETIN
·
2024
·
IF 5.3
Junyi Tan,Bo Jing,Qiuju Li,Cong Liang,Xiao Guo
It is of great significance to clarify the electrochemical behavior of Ta 5+ in LiF-NaF-K 2 TaF 7 molten salt systems for the preparation of tantalum metal by molten salt electrodeposition. The aim of this work was to explore the reaction steps and behavior of the reduction of metal Ta from Ta 5+ in fluorine molten salt by electrochemical method. The cyclic voltammetry , square wave voltammetry , chronopotentiometry were used to determine the reduction steps of Ta 5+ . The results showed that there were two reduction steps which the first reduction step R 1 was TaF 7 2 − + 2 e − ⇌ Ta F 3 + 4 F − and the second reduction step R 2 was Ta F 3 + 3 e − → Ta + 3 F − . SEM, XRD and EDS results showed that the reduction product of Ta 5+ in molten salt is Ta and the tantalum atom was selectively deposited and grew on the (200) crystal plane in priority.
研究领域:
电化学
·
材料科学
·
冶金学
·
无机化学
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DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2021
·Vol. 32
·期 10
·13409-13417
·
IF 2.478
Yu Wenjuan,Fu Xiang,dong Kexiu
Semitransparent polymer solar cells (STPSCs) are a potential photostatic structure for building-integrated photovoltaic (BIPV) application. In order to realize the application practically, the balance between efficiency, transparency, and color property is a challenge in the field. In this paper, efficient semitransparent polymer solar cells utilizing P3HT:ICBA as active layers were demonstrated. By introducing ZnSe/LiF distributed Bragg Reflector (DBR) onto the device, the power conversion efficiency (PCE) has been increased to 6.19%. In addition, this approach can also improve the color render property by leveling the transmittance spectrum. The highest color-rendering index (CRI) is achieved using device with 1 pair of DBR. As a result, the high efficiency and fine CRI confirmed that the STPSC with DBR is an effective structure for BIPV application.
研究领域:
材料科学
·
光电子学
·
可再生能源
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Hongcheng Yang,Qingyu Wen,Enzhu Li
Lithium borosilicate (LBS) and lithium fluoride (LiF) are verified to be effective sintering aids for CaAl 2 B 2 O 7 microwave dielectric ceramic to reduce the sintering temperature and lower the activation energies . Benefiting from the liquid phase sintering , low-firing, low permittivity and low-loss CaAl 2 B 2 O 7 microwave dielectric composite has been successfully obtained. Typically, CaAl 2 B 2 O 7 assembled with 1 wt % LBS composite possesses desirable properties of ε r = 5.91, Q × f = 39,443 GHz, τ f = −23.51 ppm/°C (@16.53 GHz). For composite ceramics with 0.5 wt % LiF, the optimal microwave dielectric properties are ε r = 6.08, Q × f = 37,295 GHz, τ f = −22.39 ppm/°C (@15.78 GHz). The two kinds of composite are densified at 875 °C, with co-existed CaB 2 O 4 and liquid phase. The mechanism underlying the low temperature sintering is revealed by well-matched wettability and lower activation energy of composite ceramics with additions.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2020
·
IF 6.215
Tiantian Gao,Bo Wang,Jinlong Gao,Dianlong Wang
Lithium metal is considered to be one of the most promising anode materials for next-generation energy storage systems. However, low Coulombic efficiency and dendrite growth during cycling limit the practical applications of lithium metal. In this work, a non-combustible inorganic electrolyte-LiAlCl 4 · 3SO 2 is modified with LiF additive to achieve a more stable lithium metal anode . By adding 0.3 wt % LiF to LiAlCl 4 · 3SO 2 , the ionic conductivity and lithium ion transference number of LiAlCl 4 · 3SO 2 are increased, and lithium ion migration through the solid electrolyte interface (SEI) film of lithium metal anode is easier. Thus, a more stable lithium metal anode is achieved. Therefore, at 2.0 mA cm −2 and 2.0 mAh·cm −2 , Li|Cu cells with LiAlCl 4 · 3SO 2 containing 0.3 wt % LiF can provide a stable cycling for 310 h with an average Coulombic efficiency up to 97.0%. Moreover, the addition of 0.3 wt % LiF in LiAlCl 4 · 3SO 2 can also improve the electrochemical performance of Li-SO 2 full-cell. With an areal capacity of 2 mAh·cm −2 , Li-SO 2 cell with LiAlCl 4 · 3SO 2 containing 0.3 wt % LiF can deliver ∼900 mAh·g (carbon) −1 at a discharge current densities of 0.5 A g (carbon) −1 . Therefore, we believe that a simple and effective solution is provided in this work to improve the stability of lithium metal anode with LiAlCl 4 · 3SO 2 inorganic electrolyte.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Minjing Chen,Wenyang Wang,Zhepu Shi,Zhaoping Liu,Cai Shen
Solid electrolyte interphase (SEI) grown on electrode surfaces during charge-discharge processes plays a key role in the cycle performance of lithium-ion batteries. In-situ study of cathode electrolyte interphase (CEI) is challenging due to the complicated interfacial reactions on the cathode materials including gas formation and the formation of thin CEI film. Herein, we applied the electrochemical atomic force microscope (EC-AFM) to study the interfacial changes in high energy density Li- and Mn-rich (LMR) materials with an F-rich electrolyte (1 M LiPF 6 FEC/FEMC/HFE). The study indicated that the electrolyte formed a uniform and dense passivation CEI film on the LMR material surface at high voltage. The CEI is composed of inorganic LiF substrate as confirmed by X-ray photoelectron spectroscopy (XPS). The assembled battery (LMR||Li) shows an excellent cycle performance and maintains capacity at 85.5% after 100 cycles, compared to the 13.7% retention rate of commercial carbonate electrolyte (1 M LiPF 6 EC/EMC/DMC).
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）