Small
·
2023
·Vol. 20
·期 9
·2306758
·
IF 13.3
Chen Li,Ke Liu,Dequan Jiang,Huacai Yan,En Chen,Yingying Ma,Haoming Cheng,Ting Wen,Binbin Yue,Yonggang Wang
Polymorphic phase transition is an essential phenomenon in condensed matter that the physical properties of materials may undergo significant changes due to the structural transformation. Phase transition has thus become an important means and dimension for regulating material properties. Herein, this study demonstrates the pressure-induced multi-transition of both structure and physical properties in violet phosphorus, a novel phosphorus allotrope. Under compression, violet phosphorus undergoes sequential polymorphic phase transitions. Concomitant with the first phase transition, violet phosphorus exhibits emergent insulator–metal transition, superconductivity, and dramatic switching from positive to negative photoconductivity. Remarkably, the resistance of violet phosphorus shows a sudden drop of around 10 7 along with the phase transition. In addition, piezochromism from translucent red to opaque black and suppression of photoluminescence are observed upon compression. Of particular interest is that the sample irreversibly transforms into black phosphorus with a pronounced discrepancy in physical properties from the pristine violet phosphorus after decompression. The abundant polymorphic transitions and property changes in violet phosphorus have significant implications for designing novel pressure-responsive electronic/optoelectronic devices and exploring concealed polymorphic transition materials.
研究领域:
凝聚态物理
·
材料科学
·
高压物理
·
半导体物理
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光学材料
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相变动力学
✓ 已验证
DOI
高影响因子
COLLOID AND POLYMER SCIENCE
·
2014
·Vol. 292
·期 10
·2633-2645
·
IF 2.41
Cong Houluo,Zheng Sixun
In this contribution, we reported the synthesis of poly( N -isopropylacrylamide)- block -poly(acrylic acid) (PNIPAAm- b -PAA) copolymer networks via sequential reversible addition-fragmentation chain transfer (RAFT) polymerization. The PNIPAAm- b -PAA block copolymer networks were characterized by means of Fourier transform infrared spectroscopy (FTIR) and small angle X-ray scattering (SAXS). The volume phase transition (VPT) temperatures of the PNIPAAm- b -PAA hydrogels were measured by means of micro-differential scanning calorimetry (micro-DSC). It was found that the block copolymer hydrogels displayed the VPT temperatures lower than the control PNIPAAm hydrogel. Compared to the control PNIPAAm hydrogel, the deswelling and reswelling properties of the block copolymer hydrogels were significantly improved. The improved thermoresponsive properties of the PNIPAAm- b -PAA hydrogels have been interpreted on the basis of the formation of the architecture of the block copolymer networks.
研究领域:
高分子化学
·
生物材料
·
药物递送
·
组织工程
·
智能响应材料
✓ 已验证
DOI
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 82
·52024-52029
·
IF 3.108
Xiao-Fen Sun,Zhongxia Wang,Wei-Qiang Liao,Peng-Fei Li,Jixing Gao,Yi-Yang Huang,Hai-Peng Chen,Heng-Yun Ye,Yi Zhang
In this paper, three new hybrid phase transition compounds, [Hmpy]CdBr3 (1, Hmpy = N-methylpyrrolidinuium cation), [Hmpy]2CdBr4 (2) and [Hmpy]3CdBr3·CdBr4 (3), were synthetized by means of regulating the ratio of reactants. Systematic characterizations consisting of variable temperature X-ray single crystal diffraction, differential scanning calorimetry (DSC) and dielectric measurements reveal that 1 with infinite one-dimensional (1D) [CdBr3]n− chains undergoes a phase transition around 278 K; 2 with isolated [CdBr4]2− tetrahedrons exhibits a high-temperature phase transition close to 367 K, accompanied by prominent switchable dielectric behavior. Interestingly, 1D [CdBr3]n− chains and isolated [CdBr4]2− tetrahedrons both exist in 3, associated with a phase transition at 320 K. The phase transitions in the three compounds are originated from the order-disorder transitions of the Hmpy cation. It is expected that our finding would promote the development of hybrid dielectric transition materials with adjustable properties.
研究领域:
材料化学
·
凝聚态物理
·
晶体工程
·
功能材料
·
介电材料
✓ 已验证
DOI
高影响因子
MATERIALS LETTERS
·
2014
·
IF 2.269
Yaguang Yuan,Yanping Yuan,Nan Zhang,Yanxia Du,Xiaoling Cao
Capric–myristic–palmitic acid ternary eutectic mixture (CA–MA–PA) was prepared as phase change material (PCM). A novel composite PCM of CA–MA–PA/expanded graphite (EG) with an optimum mass ratio (CA–MA–PA:EG=13:1) was prepared by uniformly absorbing CA–MA–PA into the porous network structure of the EG. The melting and freezing temperatures of CA–MA–PA/EG composite PCM were measured by differential scanning calorimeter as 18.61 °C and 16.58 °C, respectively, while the melting and freezing latent heats were 128.2 J/g and 124.5 J/g, respectively. The thermal conductivity of the CA–MA–PA/EG composite PCM was measured as 3.67 W/m K and thus the thermal storage and release rates were significantly increased. The thermal cycling test results showed that CA–MA–PA/EG composite PCM has a good thermal reliability. All the above results show that the CA–MA–PA/EG composite PCM is a potential solution for latent heat storage system.
研究领域:
材料科学
·
能源化学
·
热物理
·
功能材料
·
储能技术
✓ 已验证
DOI
高影响因子
Journal of Energy Chemistry
·
2021
·
IF 9.676
Pengfei Zhou,Jing Zhang,Zhennan Che,Zuhao Quan,Ju Duan,Xiaozhong Wu,Junying Weng,Jinping Zhao,Jin Zhou
P2-Na 0.67 Ni 0.33 Mn 0.67 O 2 is considered as a promising cathode material for sodium-ion battery (SIBs) because of its high capacity and discharge potential. However, its practical use is limited by Na + /vacancy ordering and P2-O2 phase transition. Herein, a Ti 4+ /F − co-doping strategy is developed to address these issues. The optimal P2-Na 0.67 Ni 0.33 Mn 0.37 Ti 0.3 O 1.9 F 0.1 exhibits much enhanced sodium storage performance in the high voltage range of 2.0–4.4 V, including a cycling stability of 77.2% over 300 cycles at a rate of 2 C and a high-rate capability of 87.7 mAh g −1 at 6 C. Moreover, the P2-Na 0.67 Ni 0.33 Mn 0.37 Ti 0.3 O 1.9 F 0.1 delivers reversible capacities of 82.7 and 128.1 mAh g −1 at −10 and 50 °C at a rate of 2 C, respectively. The capacity retentions over 200 cycles at −10 °C is 94.2%, implying more opportunity for practical application. In-situ X-ray diffraction analysis reveals that both P2-O2 phase transitions and Na + /vacancy ordering is suppressed by Ti 4+ /F − co-doping, which resulting in fast Na + diffusion and stable phase structure. The hard carbon//P2-Na 0.67 Ni 0.33 Mn 0.37 Ti 0.3 O 1.9 F 0.1 full cell exhibits a high energy density of 310.2 Wh kg −1 and remarkable cyclability with 82.1% retention after 300 cycles at 1 C in the voltage range of 1.5–4.2 V. These results demonstrate that the co-doping Ti 4+ /F − is a promising strategy to improve the electrochemical properties of P2-Na 0.67 Ni 0.33 Mn 0.67 O 2 , providing a facile tactic to develop high performance cathode materials for SIBs.
研究领域:
材料科学
·
电化学
·
能源存储
·
无机化学
·
固态化学
·
电池技术
✓ 已验证
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2015
·Vol. 17
·期 38
·25525-25535
·
IF 4.493
Yuanyuan Zhou,Hui Tang,Peiyi Wu
Thermo-dynamic volume phase transition mechanisms of poly[oligo(ethylene glycol)methacrylate] (POEGMA) based microgels with poly(ionic liquid) (PIL) cross-linking moieties are investigated in detail on the basis of temperature-dependent Fourier transform infrared (FTIR) spectroscopy. The original FTIR data are further analysed by two-dimensional correlation spectroscopy (2Dcos) with the perturbation correlation moving window (PCMW) technique. It is observed that the content of hydrophilic PIL cross-linking structure strongly affects the temperature induced volume phase transition mechanism of microgels in which the less cross-linked microgel exhibits a sharp volume phase transition process while the highly cross-linked microgel presents a broad transition behavior. Peculiarly, the dehydration of C–H groups acts as the driving force for the whole phase transition process within the less cross-linked microgel network and cooperative response of chemical groups is identified. It is deduced that the hydrophilic PIL moieties develop polymer–water–polymer interactions with CO groups as CO⋯D2O–PIL hydrogen bonds emerge in the less cross-linked system. As regards the highly cross-linked microgel system, the phase transition process is driven by the disruption of hydrogen bonds between CO groups and water molecules while the response of C–H groups becomes insensitive. PIL moieties passively dehydrate following the dehydration of C–H groups on oligo(ethylene glycol) side chains and no hydrogen bond between CO group and IL–D2O association appears during the phase transition process.
研究领域:
高分子科学
·
软物质物理
·
生物材料
·
药物递送
·
智能响应材料
✓ 已验证
DOI
高影响因子
Advanced Energy Materials
·
2016
·Vol. 7
·期 8
·1602149
·
IF 15.23
Shanshan Yao,Jiang Cui,Ziheng Lu,Zheng-Long Xu,Lei Qin,Jiaqiang Huang,Zoya Sadighi,Francesco Ciucci,Jang-Kyo Kim
Carbon-coated van der Waals stacked Sb 2 S 3 nanorods (SSNR/C) are synthesized by facile hydrothermal growth as anodes for sodium ion batteries (SIBs). The sodiation kinetics and phase evolution behavior of the SSNR/C anode during the first and subsequent cycles are unraveled by coupling in situ transmission electron microscopy analysis with first-principles calculations. During the first sodiation process, Na + ions intercalate into the Sb 2 S 3 crystals with an ultrafast speed of 146 nm s −1 . The resulting amorphous Na x Sb 2 S 3 intermediate phases undergo sequential conversion and alloying reactions to form crystalline Na 2 S, Na 3 Sb, and minor metallic Sb. Upon desodiation, Na + ions extract from the nanocrystalline phases to leave behind the fully desodiated Sb 2 S 3 in an amorphous state. Such unique phase evolution behavior gives rise to superb electrochemical performance and leads to an unexpectedly small volume expansion of ≈54%. The first-principles calculations reveal distinctive phase evolution arising from the synergy between the extremely low Na + ion diffusion barrier of 190 meV and the sharply increased electronic conductivity upon the formation of amorphous Na x Sb 2 S 3 intermediate phases. These findings highlight an anomalous Na + ion storage mechanism and shed new light on the development of high performance SIB anodes based on van der Waals crystals.
研究领域:
材料科学
·
电化学
·
纳米科技
·
能源存储
·
固态物理
·
计算材料学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
·
2020
·
IF 3.407
Zhonghua Li,Faqiang Shi,Limeng Liu,Jozef Vleugels,Shuigen Huang
TaC x (x = 0.5, 0.55, 0.6, 0.7) ceramics with 20 mol% Fe, Co or Ni addition were prepared by hot pressing TaC and Ta powder mixtures at 1800 °C. X-ray diffraction, scanning electron microscopy, transmission electron microscopy , high resolution transmission electron microscopy , X-ray energy dispersive spectroscopy and selected area electron diffraction were used to investigate the constituent phases and microstructures of the composites. Vickers hardness , flexural strength and fracture toughness were measured. Intermetallic compounds Fe 7 Ta 3 , Co 2 Ta and Ni 3 Ta were formed due to reactions of Fe, Co and Ni with Ta. The remaining TaC and Ta reacted to form hexagonal Ta 2 C, rhombohedral ζ-Ta 4 C 3-z or cubic TaC y depending on the overall C:Ta ratios. The microstructure of the TaC 0.5 –20 mol% Fe, Co, Ni compositions (where C:Ta = 0.5) were composed of intermetallics and fine anisotropic Ta 2 C and ζ-Ta 4 C 3-z grains. As the C:Ta ratio increased to 0.55–0.7, the ζ-Ta 4 C 3-z and TaC y grains were enlarged in size and equiaxed in the TaC 0.55 -, TaC 0.6 -, and TaC 0.7 –20 mol% Fe, Co, Ni compositions. Addition of Ni instead of Fe and Co benefitted to refine microstructures of the composites. The TaC 0.5 –20 mol% Fe, Co, Ni compositions had good flexural strength (580-650 MPa) and fracture toughness (9.3–9.5 MPa·m 1/2 ) due to growth of fine lamellar grains, despite the high Ta 2 C content.
研究领域:
材料科学
·
陶瓷
·
显微结构
·
力学性能
·
相变
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）