Processes
·
2025
·Vol. 13
·期 5
·1478
·
IF 2.8
Chao Liang,Nengwu Zhu,Fei Li,Pengfei Zhang,Pingxiao Wu,Yaxi Hu
LiFePO4(LFP) batteries are among the earliest commercialized and most discarded lithium-ion batteries. Although existing recovery technologies focus on the conversion of LiFePO4to Li2CO3, challenges associated with achieving near-full recovery and high-value products remain. This study proposes a strategy for the conversion of spent LiFePO4to LiF by mechanical chlorination coupled with a fluorination reaction. The optimum conditions were determined to be a ball-to-powder ratio (BPR) = 15, NH4Cl:LFP = 3, H2O2= 2.0 mL, rotation speed = 600 rpm, and grinding time = 12 h. Results showed that 97.14% Li was converted into LiCl by H2O2–NH4Cl mechanical chlorination. When chlorinated intermediates were immersed in water, FePO4could be harvested, and 96.79% Li could be recovered as LiF with a purity of 99.50% after adding NH4F. When Cl-functionalized renewable resin was used to exchange 99.89% F−, 0.63 g NH4Cl per litre of LiF conversion residual liquid was derived. The favourable results were attributed to the1O2generated by H2O2, which had a strong electron affinity to break Li–O bonds and provided superior conditions for the combination of Li and Cl. During fluorination, the formation of LiF reduced the ion concentration, and the entropy decreased, contributing to the spontaneous reaction. Therefore, the proposed method paves the way for near-full recovery and high-value products of spent LiFePO4.
研究领域:
材料科学
·
环境工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Chinese Journal of Aeronautics
·
2023
·
IF 5.7
Lingqi ZHU,Baozhong ZHU,Xiaolong ZHAO,Yanan WANG,Mengchen LI,Jiuyu CHEN,Yunlan Sun
Boron has a promising application in the field of propellants due to its high calorific value. However, the difficulty of ignition and the poor combustion efficiency of boron (B) have severely limited its efficient application. In response to this issue, this paper proposes to improve the ignition and combustion performance of micron-sized boron by the Polyvinylidene Fluoride (PVDF) coating. The effect of PVDF content on the B combustion performance was systematically studied using a Thermogravimetry-Differential Scanning Calorimetry (TG-DSC), a Transmission Electron Microscope (TEM), an X-Ray Diffractometer (XRD), a laser Particle Size Analyzer (PSA), and a high-speed camera. The results show that PVDF can significantly reduce the initial oxidation temperature of B powder and increase its reaction heat. When the PVDF content is 23wt%, the reaction heat and the combustion intensity of B powder reach the maximum and are significantly higher than those of the uncoated B powder. Moreover, the fluorination reaction that occurs during the combustion process not only can effectively shorten the combustion time of B powder, but also has a positive effect on its flame intensity and propagation speed, and it significantly reduces B particle agglomeration, which improves the combustion efficiency significantly. This study lays the foundation for the application of PVDF modified B in B-based solid propellants.
研究领域:
材料科学
·
燃烧学
·
推进剂技术
✓ 已验证
产品关联
DOI
高影响因子
Royal Society Open Science
·
2019
·Vol. 6
·期 3
·
IF 2.515
Zhanyang Gao,Min Wang,Shiyao Wang,Yi Wang,Ruichao Peng,Ping Yu,Yunbai Luo
A novel and efficient preparation route of insulating gas-heptafluoroisobutyronitrile was developed. The synthetic route involved halogen-exchange fluorination, decomposition of bis-(perfluoroisopropyl) ketone and dehydration reaction. Overall, the desired compound was produced without the use of extremely toxic and expensive substances. Structures of the as-obtained products were determined by 19F NMR, 13C NMR, IR and GC-MS. The effects of several variables on reaction yield including nature of potassium fluoride, the catalyst dosage, temperature, solvent and molar ratio of raw materials were all investigated. The results indicated that the total yield of heptafluoroisobutyronitrile could reach 42% from original materials under optimal conditions and the mechanism of the reaction was proposed.
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Catalysis
·
2024
·
IF 11.3
Yiwei Sun,Xiaoli Wei,Wei Zhang,Zhen Wang,Jianhai Jiang,Fangcao Liu,Bing Liu,Wenfeng Han
Conversion of potent greenhouse gases, hydrofluorocarbons (HFCs), to value-added hydrofluoroolefins (HFOs) is of great importance. AlF3 catalysts play a major role in this process. Formation and maintenance under coordinated Al are the key to prepare efficient catalysts. Herein, carbon interacted AlF3 nanoclusters catalyst (AlF3–SAPO-5) was effectively achieved with SAPO-5 molecular sieves as precursors via pyrolysis followed by in situ fluorination. This process results in a strong interaction between the carbonaceous material and active aluminum (Al) species. The results show that AlF3–SAPO-5 possesses both high activity and thermal stability. For 1,1-difluoroethane (HFC-152a) dehydrofluorination, the conversion can reach up to 95% at a reaction temperature of 350 °C. The reaction rate is almost 4 times higher than that of AlF3 prepared by traditional pyrolysis (AlF3-py). It implies that the confinement effect contributes to the formation of AlF3 nanoclusters with abundant 4- and 5-coordinated Al species stabilized by the F–Al–O–C structure. In addition, the carbon-interacted AlF3 nanoclusters exhibit superb sintering resistance. Given its fantastic activity and thermal stability, the carbon-interacted AlF3 nanoclusters show great potential for the catalytic dehydrofluorination of fluorinated alkanes.
研究领域:
化学工程
·
材料科学
·
催化反应
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Wenfeng Han,Hong Yang,Linzhe Wang,Bing Liu,Xiaoli Wei,Aimin Chen,Weiyu Song,Haodong Tang,Ying Li
Aluminum fluoride layers (AlFx) were prepared by the in situ etching of Ti 3 AlC 2 with 1,1-difluoroethane at elevated temperatures. During etching, Ti layers were fluorinated to stable TiF 3 interacting with C to confine the Al species and sublimable TiF 4 . Al layers were fluorinated to unsaturated AlFx with relatively weak Lewis acidity. Due to the sublimation of TiF 4 , more AlFx acting as the main active centers were exposed to the reactants, and the surface areas of the confined-AlFx were increased, which contributed to the enhanced activity of the catalyst. The evaluation of the dehydrofluorination reaction showed that confined-AlFx layers presented higher reaction rate than F-γ-Al 2 O 3 and AlF 3 . Besides, it was unexpected that TiF 3 also exhibited activity for the reaction, even though the activity was much lower than confined-AlFx. Finally, the experimental results were confirmed by DFT calculations.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Yuxiang Li,Kaili Zhang
Aluminum powder is widely used as a high-energy fuel in the domain of energetic materials, while the oxidation kinetics of Al is limited by the oxide shell on the particle surface which acts as a reaction barrier. Recently, transition metal fluorides have emerged as an intriguing type of fluorine-containing oxidizers which can improve reactivity of Al through interfacial fluorination. However, most previous research focused on micron-sized fluorides, while the reactivity of nanosized fluoride in energetic composite was rarely studied. In this work, nanosized NiF 2 (∼100 nm) was synthesized through a facile and safe approach, and it was coupled with nanosized and micron-sized Al powders to form energetic composites. Regardless of dimension of Al, Al/NiF 2 composite exhibited higher specific heat release, higher reaction efficiency, and lower reaction temperature than that of corresponding Al/NiO composite. Post-characterizations suggested that elemental Ni and AlF 3 were produced from the reaction of Al/NiF 2 composite at 710 °C, and AlF 3 was found to evaporate over 900 − 1050 °C. The long-term stability of energetic composites was evaluated through a real-time aging test for 12 months, and only slight energy degradation (<7.5 %) was founded in Al/NiF 2 composite. Concerning combustion behavior, Al/NiF 2 composite showed relatively low flame brightness but a comparable pressure generation compared to Al/NiO composite, which is presumably attributed by the endothermic evaporation of AlF 3 . A notable finding is that hybrid Al/NiF 2 /NiO composite exhibits superior pressure output, and this composite is rather explosive even for small charge amount, which shows the potential as a novel primary explosive.
研究领域:
材料科学
·
燃烧与爆炸领域
✓ 已验证
产品关联
DOI
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2017
·
IF 2.858
Jianquan Tan,Weiqu Liu,Zhengfang Wang
Novel comb-shaped fluorinated (meth)acrylate copolymer was synthesized and used as reactive modifier for epoxy resins. The chemical structure of the comb-shaped fluorinated reactive modifier (CFRM) was characterized by GPC, FTIR and 1 HNMR. In addition, a random fluorinated reactive modifier (RFRM) which possessed the same chemical composition but random structure was developed as a contrast modifier. Thorough performances of the modified thermosets modified with these two modifiers were investigated. Surface energy, surface composition and surface morphology were investigated by means of contact angle test, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Compared to the CFRM with RFRM, epoxy thermosets modified with CFRM performed lower surface energy, higher fluorine atomic concentration at the surface and rougher surface morphology. The thermosets modified with CFRM possessed even lower surface energy (18.32 mN/m) than polytetrafluoroethylene (18.50 mN/m) with just adding 0.05 wt% fluorine component (DFHMA structural unit), indicating its high efficiency and effectivess in improvement of surface hydrophobicity. Tensile strength tests and glass transition determined by dynamic mechanical thermal analysis (DMTA) showed that both tensile strength and Tg decreased slightly by incorporation of the two reactive modifier since the sofer segments were incorporated. And thermosets modified with CFRM performed slightly lower Tg than that of RFRM. The influence of the reactive modifier on Shore D hardness and thermal stabilities was not significant due to the low concentrations. The incorporation of the CFRM was more advantageous to lowering water absorption while the optical transmittance deteriorated. The hydrophobic epoxy resins modified with comb-shaped fluorinated reactive modifier might have the potential application in anti-fouling coatings and other occasions requiring low surface energy.
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
Arabian Journal of Chemistry
·
2022
·
IF 6.212
Linzhan Bai,Xinyan Wang,Xichao Sun,Jiao Li,Lilan Huang,Haibin Sun,Xueli Gao
Development of electrospun nanofiber membranes with the selective wettability characteristics for effectively separating oil–water mixtures is an extremely advisable strategy. In this study, a superhydrophobic electrospinning carbon nanofiber (F/ZnO/CNF) membrane was successfully prepared by electrospinning and in-situ growth of ZnO, and subsequent fluorination reaction with 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane (POTS). Benefiting from the influence of needle-like nanostructure and low surface energy, the as-prepared F/ZnO/CNF membrane shows excellent superhydrophobicity. When the growth duration of ZnO is 3 h, the obtained F/ZnO/CNF-3 membrane possesses outstanding water contact angle (WCA, 159.7°) and splendid oil–water separation efficiency (>99 %). Meanwhile, due to its the superior environmental stability the obtained F/ZnO/CNF-3 membrane exhibits excellent low and high temperature resistance, and enhanced resistance to various organic solvents in the face of a series of harsh environments.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
CARBON
·
2021
·
IF 9.594
Jian Liu,Xin Li,Lingie Zhang,Xiangyang Liu,Xu Wang
The transformation of graphene into sp 3 -bonded carbon films through ultra-high pressure, hydrogenation or fluorination has been studied for years. It is considered that only few layers of graphenes on metal surfaces can realize this transformation and the electron orbitals hybridization between metal substrate and graphene layer is thought to be the drving force and stabilize the formed sp 3 carbon structure. Here, we use nanographene molecule, hexa-peri-hexabenzocoronene (HBC), as the model compound to exploit the fluorination reaction between graphene and fluorine gas. MALDI-TOF mass, XPS and XRD results show that the direct fluorination realized the intermolecular cross-linking of nanographene molecules without the assistence of mental substrate. Combining with theoretical calculation and EPR test results, we proved that the fluorination of nanographene molecules with F 2 follows a free-radical mechanism, and the carbon radicals formed during fluorination caused the covalent cross-linking between graphene molecules which have a tight π-π stacking. Meanwhile, the fluorination of other small nanographene molecules, pyrene and perylene, further confirmed the universality of this free-radical cross-linking mechanism. This would provide a further understanding for the chemical transformation from graphene layers to 2D diamond structure under chemical adsorption process.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2016
·Vol. 51
·期 24
·11002-11013
·
IF 2.302
Han Wenfeng,Wang Zhikun,Li Xiaojuan,Tang Haodong,Xi Miao,Li Ying,Liu Huazhang
Nano-Cr 2 O 3 was prepared via solution combustion synthesis (SCS) with Cr(NO 3 ) 3 ·9H 2 O as the Cr precursor and glycine as the fuel. The effect of molar ratio of glycine to Cr in the feed during solution combustion was investigated. Cr 2 O 3 samples were characterized by XRD, SEM, TEM, H 2 -TPR, and XPS. In addition, these catalysts were evaluated for the dehydrofluorination of 1,1-difluoroethane producing vinyl fluoride (VF, CH 2 =CHF). The results confirm that Cr 2 O 3 is in relatively uniform flakes or flat particles via solution combustion synthesis with the particle size of 50–200 nm and composed by the aggregation of 58–77 nm nanoparticles. The specific surface area of higher than 30 m 2 g −1 is achieved, which is comparable to the values obtained by solvothermal route. For the dehydrofluorination of 1,1-difluoroethane, high conversion levels (83 % for commercial catalyst and 93 % for SCS catalyst) are achieved at 350 °C, and the activity of SCS catalyst is at least 2× higher than that of commercial Cr 2 O 3 at reaction temperatures below 300 °C. Compared with commercial Cr 2 O 3 , XPS, and H 2 -TPR reveal the higher CrO 3 contents on the surface of Cr 2 O 3 derived from SCS. It is suggested that CrO 3 plays a major role in the catalytic performance as high-valent Cr species such as Cr(VI) are vital for the reaction because they could be transformed to the active species such as CrO
x
F
y
. In addition to the high activity, compared with commercial Cr 2 O 3 , SCS catalyst also show higher stability. Following the reaction of 120 h at 300 °C, no noticeable deactivation is observed while the activity of commercial Cr 2 O 3 declines with TOS. High surface area and much smaller size of Cr 2 O 3 crystalline favors the formation of CrO
x
F
y
during reaction over Cr 2 O 3 -3.33 catalyst probably contribute to the high activity and stability.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
Organic Chemistry Frontiers
·
2017
·Vol. 4
·期 10
·1958-1961
·
IF 4.955
Liyan Wang,Xiaohuan Jiang,Pingping Tang
The first example of a silver-mediated fluorination of alkyl iodides with the Ruppert–Prakash reagent (TMSCF3) as a fluorinating agent has been reported. This reaction is compatible with a variety of functional groups and proceeds under mild reaction conditions. Moreover, we demonstrate that the large surface area of CaF2 dramatically increased the reaction yield.
研究领域:
有机化学
·
药物化学
·
合成方法学
·
氟化学
·
转化医学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）