JOURNAL OF POWER SOURCES
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2017
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IF 6.395
Jinchao Li,Suqin Liu,Zhen He,Zhi Zhou
A novel branched side-chain-type sulfonated polyimide (6F-s-bSPI) membrane with accessible branching agents of melamine , hydrophobic trifluoromethyl groups ( CF 3 ), and flexible sulfoalkyl pendants is prepared by a high-temperature polycondensation and post-sulfonation method for use in vanadium redox flow batteries (VRFBs). The chemical structure of the 6F-s-bSPI membrane is confirmed by ATR-FTIR and 1 H NMR spectra. The physico-chemical properties of the as-prepared 6F-s-bSPI membrane are systematically investigated and found to be strongly related to the specially designed structure. The 6F-s-bSPI membrane offers a reduced cost and possesses a significantly lowered vanadium ion permeability (1.18 × 10 −7 cm 2 min −1 ) compared to the linear SPI (2.25 × 10 −7 cm 2 min −1 ) and commercial Nafion 115 (1.36 × 10 −6 cm 2 min −1 ) membranes, prolonging the self-discharge duration of the VRFBs. In addition, the VRFB assembled with a 6F-s-bSPI membrane shows higher coulombic (98.3%–99.7%) and energy efficiencies (88.4%–66.12%) than that with a SPI or Nafion 115 membrane under current densities ranging from 20 to 100 mA cm −2 . Moreover, the VRFB with a 6F-s-bSPI membrane delivers a stable cycling performance over 100 cycles with no decline in coulombic and energy efficiencies. These results show that the branched side-chain-type structure is a promising design to prepare excellent proton conductive membranes.
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Journal of Energy Chemistry
·
2024
·
IF 14
Yongjun Kang,Nanxi Dong,Fangzhou Liu,Daolei Lin,Bingxue Liu,Guofeng Tian,Shengli Qi,Dezhen Wu
Silicon-based materials have demonstrated remarkable potential in high-energy–density batteries owing to their high theoretical capacity. However, the significant volume expansion of silicon seriously hinders its utilization as a lithium-ion anode. Herein, a functionalized high-toughness polyimide (PDMI) is synthesized by copolymerizing the 4,4′-Oxydiphthalic anhydride (ODPA) with 4,4′-oxydianiline (ODA), 2,3-diaminobenzoic acid (DABA), and 1,3-bis(3-aminopropyl)-tetramethyl disiloxane (DMS). The combination of rigid benzene rings and flexible oxygen groups (-O-) in the PDMI molecular chain via a rigidness/softness coupling mechanism contributes to high toughness. The plentiful polar carboxyl (–COOH) groups establish robust bonding strength. Rapid ionic transport is achieved by incorporating the flexible siloxane segment (Si-O-Si), which imparts high molecular chain motility and augments free volume holes to facilitate lithium-ion transport (9.8 × 10 − 10 cm 2 s −1 vs. 16 × 10 − 10 cm 2 s −1 ). As expected, the SiO x @PDMI-1.5 electrode delivers brilliant long-term cycle performance with a remarkable capacity retention of 85% over 500 cycles at 1.3 A g −1 . The well-designed functionalized polyimide also significantly enhances the electrochemical properties of Si nanoparticles electrode. Meanwhile, the assembled SiO x @PDMI-1.5/NCM811 full cell delivers a high retention of 80% after 100 cycles. The perspective of the binder design strategy based on polyimide modification delivers a novel path toward high-capacity electrodes for high-energy–density batteries.
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Energy Materials
·
2024
·Vol. 4
·期 5
·N
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IF 11.8
Hui Chang,Guohong Kang,Zengqi Zhang,Wei Liu,Yongcheng Jin
Safety hazards associated with separators in lithium-ion batteries are more pronounced in light of the significant improvement of energy density of batteries, hindering their wide application. In this research, asymmetric poly (vinylidene fluoride) (PVDF)-coated polyimide separators with three-dimensionally homogeneous microporous (3DHM API/PVDF) structure are prepared, in which a PVDF layer with a thickness of 6 μm on one side of polyimide. Polyimide, as the base film, has a high heat-resistant temperature which ensures that as-prepared separators will not be shrunk and burned. The coated PVDF layer imparts 3DHM API/PVDF with thermal shutdown function at 175 °C due to the melting of PVDF. The temperature difference between the shutdown and meltdown temperature is over 100 °C, ensuring that the LIB assembled with 3DHM API/PVDF is safe for use. Moreover, the interconnected microporous structure of the separator facilitates the formation of 3D Li+ transport pathways and uniformity of lithium deposition, suppressing lithium dendrite growth. The coin cells assembled by 3DHM API/PVDF exhibit similar electrochemical performance to that of a commercial polypropylene separator at room temperature. Therefore, the novel 3DHM API/PVDF separator may be a promising candidate for a significantly safer LIB.
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JOURNAL OF CHROMATOGRAPHY A
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2024
·
IF 3.8
Yuqian Xiang,Xiaohui Yan,Cheng Chen,Yaoshen Guo,Hongxing Liu,Yanshuo Li,Dapeng Wu
In this work, porous polyimide microfibers (PI-μF) were prepared by high-pressure wet spinning method, and successfully applied as adsorbents for solid phase extraction (SPE) of fluoroquinolones (FQs) in water and food samples. The PI-μFs of ∼10, 25, 50, 100 μm in diameter could be controlled by the inner diameter of quartz capillary nozzles. The flow resistance of SPE cartridges packed with 10 μm PI microfiber (10-PI-μF) and 25-PI-μF was comparable to or even lower than that of commercial SPE cartridges, while the flow resistance of 50-PI-μF and 100-PI-μF SPE cartridges was increased obviously due to tiny broken pieces. The 10-PI-μF and 25-PI-μF have a specific surface area of 102 m 2 g −1 and 76 m 2 g −1 , mesopores of 22–32 nm, and large breakthrough volume of 110 mL/5 mg and 85 mL/5 mg for FQs, while the 50-PI-μF and 100-PI-μF had much lower specific surface area and hardly had retention for FQs. FQs from tap water, egg and milk samples were then extracted by PI-μF SPE, and analyzed by high performance liquid chromatography-fluorescence detector (HPLC-FLD). SPE parameters as type of elution solvent, elution solvent volume, pH value of sample solution, flow rate of sample solution, and breakthrough volume were first optimized in detail. Under the optimal conditions, the PI-μF SPE/HPLC-FLD method showed high recoveries (96.8%–107%), wide linearity (0.05–50 μg L −1 , or 0.01–10 μg L −1 ), high determination coefficients (R 2 ≥0.9992), and low limits of detection (LODs, 0.005–0.014 μg L −1 ). For the real tap water, egg and milk samples, the recoveries and RSDs were 81–119% and 0.8–9.8%, respectively. The results show that porous microfiber up to 25 μm in diameter is a promising solid-phase extraction adsorbent with the lowest flow resistance that can be used for trace organic pollutants in water and food samples.
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PubMed
高影响因子
POLYMER
·
2024
·
IF 4.1
Long Ni,Yinfu Luo,Lu Shen,Chen Qiu,Liwei Yan,Mei Liang,Shengtai Zhou,Huawei Zou
Multifunctional porous materials demonstrate ubiquitous applications in the fields of flame retardancy, thermal insulation and electromagnetic interference (EMI) shielding. In this work, a series of lightweight polyimide/silica aerogel (PIF/SiA) foams with exceptional thermal stability, flame retardancy and thermal insulation performance were prepared by employing microwave-assisted foaming and thermal imidization treatment, using polyester ammonium salt/silica aerogel (PEAS/SiA) powders as the derivative precursors. The limiting oxygen index and fire growth rate reached as high as 58.2 % and as low as 0.1 kW/(m 2 ·s) for PIF/SiA composite foams, respectively, which was a result of the formation of micro/nano multi-scale pore structure of PIF skeleton and the “pearl-necklace-like” skeletal network of nano SiA. In addition, the PIF/SiA composite foams exhibited excellent thermal insulation and infrared stealth performance, which demonstrate a potential for long service life in fire protection use. Furthermore, the carbonized PIF/SiA (i.e., PICF/SiA) foams possessed enhanced mechanical (improvement of 117.6 %) and EMI shielding performance (specific EMI shielding effectiveness: 8541.9 dB/(g/cm 2 )) when compared with the original PIF/SiA composite foams. To sum up, a facile method was proposed to fabricate multifunctional PIF-based composite foams and their derived carbon foams for flame retardancy, thermal insulation and EMI shielding applications in high-end engineering sectors.
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ADVANCED ENGINEERING MATERIALS
·
2024
·Vol. 26
·期 23
·2401659
·
IF 3.4
Song Han,Liu Zhang,Gaohui Sun,Jun Wang,Shihui Han
Composites comprising conductive polymers and metal particles have garnered considerable interest in sensor technology due to their excellent electrical conductivity. However, producing controllable pressure sensors that retain high sensitivity under microstress remains challenging. Polyimide (PI) sponge exhibits excellent chemical and thermal stability and a porous structure that facilitates considerable deformation under low stress levels and results in good sensitivity to external forces. Herein, a conductive polymer–metal composite conductive phase, polypyrrole–silver (PPy–Ag), is directly fabricated on the PI surface through incipient network conformal growth. This method ensures that the PPy–Ag composite maintains optimal performance within its original temperature range, thereby enhancing detection sensitivity at low stress levels. The maximum conductivity of the fabricated PPy–Ag/PI composite sponge-based flexible piezoresistive sensor is 2.42 × 10 −4 S m −1 , and the sensitivity is recorded at 16.31 kPa −1 within a stress range of 0–80 Pa. After undergoing 1000 compression cycles, the sensor exhibits commendable stability and reproducibility.
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JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
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2018
·Vol. 85
·期 3
·506-513
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IF 1.745
Fei Zhifang,Yang Zichun,Chen Guobing,Li Kunfeng
Abstract Polyimide cross-linked silica aerogels with different weight percentages of polyimide were prepared through sol–gel technology and supercritical CO 2 fluid drying technology. Tetraethoxysilane (TEOS) was used as a silica source precursor, 3-aminopropyltriethoxysilane (APTES) end-capped polyimide was used as a cross-linking agent, derived from 3, 3′, 4, 4′-biphenyltetracarboxylic dianhydride (BPDA) and 4, 4′-oxydianiline (ODA). The acid produced during the imidization process catalyzed the hydrolysis reaction without additional catalyst. After condensation reaction catalyzed by ammonium hydroxide solution, the polyimide cross-linked silica gels were obtained and then dried in supercritical CO 2 . The polyimide cross-linked silica aerogels have low density (0.132~0.187 g/cm 3 ), high specific surface area (623–741 m 2 /g), low thermal conductivity (0.0306~0.0347 W/m K at room temperature), relatively high compressive strength (1.03~3.82 MPa) and high thermal decomposition temperature (360 °C). This research provided a simple and efficient method that used the polyimide as a strengthening phase to improve the mechanical properties of TEOS-based silica aerogels.
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CHEMICAL ENGINEERING JOURNAL
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2024
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IF 13.3
Jiankun Cao,Yumo Chen,Hailiang Nie,Hongyuan Yan
Polyimide nanofiber aerogels loaded with thymol blue and hydroxylamine sulfate (TB-HAS@PI NFAs) were synthesized and employed as a novel sensor for colorimetric detection of breath acetone (BrAce). The enhancement of 3D multi-level pore structure of TB-HAS@PI NFAs for sensing performance was elucidated through systematical characterization results. Because the designed sensing system relied on the specific reaction of HAS with acetone, TB-HAS@PI NFAs exhibited a more sensitive response ability to acetone, ensuring that the colorimetric sensing detection will not be interfered by other coexisting gas in exhaled breath. Moreover, the sensor demonstrated a rapid response, with color changes quantitatively measured within 30 s of exposure to acetone gas. Importantly, the feasibility and accuracy of established method were confirmed through comparison with GC–MS. This research provided a promising strategy for daily health management of healthy people and diabetics.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2024
·
IF 8.1
Chen Yang,Dong Xie,Suzhe Li,Luyuan Song,Zixuan Yuan
Polyimide (PI) nanofiber materials have garnered attention in the field of high-temperature filtration due to their exceptional thermal stability. Enhancing their filtration efficiency for fine particulate matter (PM2.5–0.3) and exploring their performance limits under high-temperature conditions are crucial for high-temperature filtration applications. In this study, a metal wire-based needle-free electrospinning technique was employed to electrospin polyimide (PI) material, successfully fabricating nanofiber membranes with an average fiber diameter of 122 nm within just 10 min at an elevated electrospinning voltage of 80 kV (electric field:333.33 kV/m). The Fine-diameter PI nanofiber membrane achieved a filtration efficiency of 99.99 % for PM0.3 and operated at a low resistance of 189.18 Pa. After continuous treatment at a high temperature of 390 °C for one hour, the Fine-diameter PI nanofiber membrane still maintained a filtration efficiency of 99.96 % for PM0.3 and was capable of completely filtering PM2.5. This demonstrates the excellent stability and reliability of the Fine-diameter PI nanofiber membrane under extreme temperature conditions. Additionally, the membrane exhibited outstanding hydrophobic properties, with a static contact angle of 130 ± 3°, aiding in maintaining its filtration performance in humid environments. The Fine-diameter PI nanofiber membrane developed in this study offers a novel fabrication strategy for PM filtration in high-temperature environments and provides new insights into its limit performance.
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ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Long Ni,Xiaoting Liao,Ke Yang,Hang Ye,Hexing Sun,Yinfu Luo,Liwei Yan,Shuang Xia,Mei Liang,Shengtai Zhou,Huawei Zou
In this work, the fabrication of lightweight, hydrophobic, and high-temperature thermal insulative polyimide foam-derived carbon foams (PICFs) with an anisotropic pore structure was proposed. First, polyester ammonium salt (PEAS) precursor powders with different component moieties were synthesized by a copolymerization method. Then, the PEAS powders were subjected to microwave-assisted foaming, thermal imidization, and carbonization processes to prepare PICFs. The “bottom-up” directional foaming behavior and high carbon yield of polyimide foams (PIFs) constructed regular honeycomb-like pores in the vertical direction and aligned ellipsoidal strip-like pores in the horizontal direction of the PICFs. Results showed that the PICFs possessed low density (20–40 kg/m3), small pore size (128 μm), favorable mechanical properties (compressive strength of 86.01 kPa) and excellent thermal stability (T5% > 800 °C). By combining micro/nano porous structures with reduced pore diameters, the PICFs exhibited excellent hydrophobicity, with a water contact angle of up to 128.8° in the vertical direction and 121.2° in the horizontal direction. The PICFs demonstrated superior thermal insulation properties at both room temperature and high temperatures, with thermal conductivity values ranging from 0.0335 to 0.1887 W/(m·K) between 25 and 1000 °C. Thus, lightweight, hydrophobic, and high-temperature thermal insulative PICFs were successfully prepared using the proposed method, which has potential applications in high-end engineering fields such as aerospace, transportation, microelectronics, and nuclear energy sectors, among others.
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PubMed
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2025
·
IF 8.3
Yan He,Jinpeng Guo,Chuanchuan Bi,Zhifei Hao,Chunping Li,Qi Wang,Xiaogang Han
The safety and high mechanical strength of all-solid state lithium battery are the main challenges that limit their development and application. Although polypropylene (PP) separators have excellent mechanical properties, their poor thermal stability remains a problem that requires immediate attention. Herein, a sandwich-structured composite solid electrolyte consisting of polyimide-Celgard-polyimide/PEO-LiTFSI (PI-PP-PI/PEO-LiTFSI) is reported for use in lithium metal batteries. The presence of a carbonyl group in the PI enhances its overall electrochemical performance and thermal stability. The composite solid electrolyte exhibited an ionic conductivity of 1.32 mS/cm at 60 °C and a tensile strength of up to 21.1 Mpa. Particularly, we discovered that the film maintained its shape without deformation at 180 °C, thereby facilitating steady cycling of the lithium battery for 1600 h at 0.1 mA/cm 2 and demonstrating excellent resistance to lithium dendrite formation. After 120 and 150 cycles at 0.2 C and 1 C, respectively, the capacity was 104.8 and 79.60 mAhg −1 and the coulombic efficiency was close to 100%. This study provides a potential strategy for the development of solid-state lithium-metal batteries with excellent mechanical properties and high-temperature resistance.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Hongyu Chen,Wenjun Jiang,Keqi Shi,Chunlin He,Guoyuan Yuan,Bo Yu,Min Li,Jian Feng
The separation and upcycling of nickel from industrial wastewater is significant because it is harmful to the environment and human health. With the development of special engineering plastics industry, a substantial amount of polyimide (PI) scrap is generated. In this study, an amine and carboxyl functionalized PI (PI-AC) was prepared from waste-derived PI foam for the adsorption and separation of Ni(II). The adsorption performance of PI-AC can be modulated by adjusting the ratio of functional groups. PI-AC demonstrated rapid adsorption kinetics (<5 min) for Ni(II) and effectively adsorbed Ni(II) from real wastewater in column experiments. PI-AC shows a competitive dynamic adsorption capacity for Ni(II) (222.59 mg/g) as compared with most of the reported adsorbents. Furthermore, the successful removal of Ni from low-concentration simulated Ni-containing wastewater (7.18 mg/L) results in a residual Ni concentration (0.001 mg/L) that complies with the emission standard. The porous structure of the PI foam enables rapid adsorption of nickel and column adsorption was successfully achieved. The adsorption performance exhibited maintained stably even after five cycles, demonstrating excellent recoverability. The characterizations, comparison studies, and DFT calculations demonstrated that one nitrogen atom in the amine group and one oxygen atom in the carboxyl group act as a bidentate ligand to chelate with Ni(II). This study opens a new way for the treatment of wastewater using PI foam scrap, which coincides with the idea of “treating the waste with waste”.
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危险品化学品经营许可证（带存储）