ELECTROCHIMICA ACTA
·
2023
·
IF 6.6
Xiaocong Zhong,Yahui Ren,Kuifang Zhang,Huai Jiang,Ruixiang Wang,Zhifeng Xu
Incorporating oxygen evolution catalytic particles into the Pb matrix via a powder mixing-pressing-sintering process is an effective strategy to develop efficient lead-dispersed particle (Pb-DP) composite anodes for nonferrous metal electrowinning . Catalytic particles are demonstrated to significantly reduce the anodic potential of Pb-DP anodes. However, the intrinsic contribution of catalytic particles to the electrochemical performance of Pb-DP anodes remains obscure. Herein, Pb-DP anodes with different dispersed particles (chemically inert Si or C, catalytic Co 3 O 4 or MnCo 2 O 4 ) were prepared. The anodic potential, microstructure and phase composition of the oxide layer, and oxygen evolution behavior of these Pb-DP anodes were investigated and compared with those of the Pure-Pb anode (prepared without dispersed particles). The results showed that compared with the Pure-Pb anode, Pb-Si and Pb-C anodes present similar microstructures and phase compositions of the oxide layer. However, they exhibit a larger Tafel slope for the oxygen evolution reaction (OER). Although the incorporation of catalytic particles (Co 3 O 4 and MnCo 2 O 4 ) reduced the thickness and specific surface area of the oxide layer and inhibited PbO 2 growth, the presence of Co 3 O 4 and MnCo 2 O 4 significantly reduced the Tafel slope and charge transfer resistance ( R ct ) of the OER. Consequently, the anodic potentials of Pb-Co 3 O 4 and Pb-MnCo 2 O 4 are approximately 45 mV and 69 mV lower than that of Pure-Pb, respectively. It is demonstrated that the lower anodic potential of the Pb-Co 3 O 4 and Pb-MnCo 2 O 4 composite anodes originates from the catalytic activity of the dispersed particles rather than the physical effect of the dispersed particles.
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Polymers
·
2023
·Vol. 15
·期 22
·4429
·
IF 5
Baokai Wang,Shiqin Wan,Mengyang Niu,Mengyi Li,Chang Yu,Zheng Zhao,Weiwei Xuan,Ming Yue,Wenbin Cao,Qi Wang
With the miniaturization of current electronic products, ceramic/polymer composites with excellent thermal conductivity have become of increasing interest. Traditionally, higher filler fractions are required to obtain a high thermal conductivity, but this leads to a decrease in the mechanical properties of the composites and increases the cost. In this study, silicon nitride nanowires (Si3N4NWs) with high aspect ratios were successfully prepared by a modified carbothermal reduction method, which was further combined with AlN particles to prepare the epoxy-based composites. The results showed that the Si3N4NWs were beneficial for constructing a continuous thermal conductive pathway as a connecting bridge. On this basis, an aligned three-dimensional skeleton was constructed by the ice template method, which further favored improving the thermal conductivity of the composites. When the mass fraction of Si3N4NWs added was 1.5 wt% and the mass fraction of AlN was 65 wt%, the composites prepared by ice templates reached a thermal conductivity of 1.64 W·m−1·K−1, which was ~ 720% of the thermal conductivity of the pure EP (0.2 W·m−1·K−1). The enhancement effect of Si3N4NWs and directional filler skeletons on the composite thermal conductivity were further demonstrated through the actual heat transfer process and finite element simulations. Furthermore, the thermal stability and mechanical properties of the composites were also improved by the introduction of Si3N4NWs, suggesting that prepared composites exhibit broad prospects in the field of thermal management.Keywords:silicon nitride nanowires;thermal interface materials;ice template method;thermal conductivity
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Journal of Energy Storage
·
2023
·
IF 9.4
Yuan Qiao,Ali Reza Kamali
Thermally modified polyimide (PI) is investigated as an efficient binder to enhance the Li-ion storage performance of silicon nanoparticles . Heat-treatment of Si@PI electrodes results in an optimized charge transfer complex (CTC) structure, which improves the electrochemical performance of the electrode by forming a compact structure that reduces the charge transfer impedance, significantly enhancing the cycling performance of the silicon anode . Electrodes subjected to the heat-treatment at 350 °C (Si@PI-350) exhibit a charge transfer impedance of 37.67 Ω combined with a reversible Li + storage capacity of 2334 mAh g −1 recorded after 30 cycles at 200 mA g −1 , in comparison to the original Si@PI electrodes showing an enhanced impedance value of 130.4 Ω and reduced capacity of 737 mAh g −1 . At a high current density of 2000 mA g −1 , the capacity of Si@PI-350 (1001 mAh g −1 ) is significantly greater than Si@PI (455 mAh g −1 ) highlighting the efficiency of the CTC structures formed during the thermal treatment. We suggest that the thermal treatment of Si@PI electrodes at optimal conditions can significantly affect the Li-ion insertion/extraction cycling performance of silicon nanoparticles.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Chongyang Tao,Lanyun Li,Ni He,Guodong Sun,Chengze Liu,Junjie Xu,Mingyang Li,Longlong Dong,Yusheng Zhang,Lianwen Wang,Mingjia Li
In this study, low energy ball milling and spark plasma sintering techniques prepared the in-situ synthesized Ti 5 Si 3 reinforced Ti-6Al-4V (TC4) matrix composites and then rolled them at high temperatures. In the composites with high Si content, the Ti 5 Si 3 particles distributed at the interface of α-phase and β-phase agglomerated and then formed a quasi-continuous network structure, which will deteriorate the plasticity of the composites. After hot rolling, the grains of the composite were significantly refined, and more Ti 5 Si 3 particles were precipitated. With the increase in Si content, the tensile strength of sintered composites increased slightly, but the elongation decreased greatly. After hot rolling, the tensile strength of the composite increased significantly with an increment of 359.4 MPa, among which the composite with 0.6 wt% Si achieved a synchronous increase in strength and plasticity. The strengthening mechanism of sintered composites included dislocation strengthening, solution strengthening, and grain refinement, among which dislocation strengthening and grain refinement were the main strengthening mechanisms. The strengthening mechanism of rolled composites was mainly the dislocation strengthening caused by rolling, the grain refinement, and the mismatch of thermal expansion coefficient.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Min Liu,Zhendong Yao,Wenqing Li,Jing Zhang,Chao Li,Xu Huang,Jiaguang Zheng,Liuting Zhang,Meiqiang Fan
Silicon is considered as a promising portable hydrolytic hydrogen production material due to its abundant raw materials, high theoretical capacity (1600 mL/g) and facile storage. However, the low hydrolysis activity and slow hydrolysis rate of silicon hinder its practical application. To address this issue, we introduced CaH 2 to form Si-based composites via a flexible ball milling method. The above composites showed ideal yield (1216 mL/g in 10 min), reaction conversion (95.5%) and fast hydrolysis kinetics (225 mL/(s·g)) in deionized water, which is one of the best hydrolysis performances of Si-based composites so far. The hydrolytic process can be divided into two steps: the splitting hydrolysis of CaH 2 and the continuous hydrolysis of Si. Combining the dynamic in-situ structural analysis with the analogue simulation, it can be confirmed that the formation of local high concentration alkali field is the key to promote the complete hydrolysis and achieve high yield and fast kinetics of the composites. The existence of lattice defects was proved and the adsorption of Si to hydroxide ion was proved by theoretical calculation. Our work provided a novel idea for the theoretical design of hydrolytic hydrogen production compounds and promoted the practical application of low cost and portable hydrolytic hydrogen production materials.
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JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2023
·Vol. 332
·期 11
·4477-4488
·
IF 1.6
Zou Jin-Zhao,Xu Shi-Zhuan,Wang Peng,Cao Chang-Qing,Yan Chao,You Yan,Lu Jun-Qiang,Zhu Li-Bing,Zhu Zhi-Yong,Lin Jun
A solid-phase metallurgy combined with spark plasma sintering technology was used to prepare U 3 Si 2 pellets. The thermal conductivity and oxidation behavior of the pellets were studied. The pellets were highly dense (> 98% theoretical density) and had an ultra-high phase purity. The thermal conductivity of the U 3 Si 2 pellets increased linearly with temperature from 300 to 973 K. By further annealing the pellets at 300 °C in air for two hours, the oxidation onset temperature was increased from 490 to 520 °C. A mechanism of pore passivation was proposed to account for the enhanced oxidation resistance.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2021
·
IF 5.316
Mingwei Liang,Weijing Wang,Yi Jiang,Chenyang Liao,Qin Long,Xuefei Lai,Li Liao
The commercial application of silicon is still impeded by poor conductivity and significant volume change. In this work, a C@Si@G composite was synthesized by a facile chemical solution reaction and carbonization procedure with cocoon silk as a natural carbon source. This composite has a sandwich structure, where Si nanoparticles as a sandwich middle layer and graphene (G) as an out layer. And it possesses the advantages of flexible, nitrogen-doped and is environmentally friendly. The optimized C@Si@G-15 composite is used as a self-supporting anode without a current collector, and it shows a reversible discharge capacity of 972 mAh g −1 after 120 cycles at 1 A g −1 and a relatively high capacity of 1070 mAh g −1 after 300 cycles at 200 mA g −1 , demonstrating the effect of coating the N-doped carbonized silk and the graphene synergistically to improve electrical connectivity and to constrain the pulverization of Si nanoparticles. Hence, it delivers great potential for application on wearable devices .
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ACS Nano
·
2021
·
IF 15.881
Zehang Zhou,Quancheng Song,Bingxue Huang,Shiyi Feng,Canhui Lu
The development of modern electronics has raised great demand for multifunctional materials to protect electronic instruments against electromagnetic interference (EMI) radiation and ice accretion in cold weather. However, it is still a great challenge to prepare high-performance multifunctional films with excellent flexibilty, mechanical strength, and durability. Here, we propose a layer-by-layer assembly of cellulose nanofiber (CNF)/Ti3C2Tx nanocomposites (TM) on a bacterial cellulose (BC) substrate via repeated spray coating. CNFs are hybridized with Ti3C2Tx nanoflakes to improve the mechanical properties of the functional coating layer and its adhesion with the BC substrate. The densely packed hierarchical structure and strong interfacial interactions endows the TM/BC films with good flexibility, ultrahigh mechanical strength (>250 MPa), and desirable toughness (>20 MJ cm–3). Furthermore, benefiting from the densely packed hierarchical structure, the resultant TM/BC films present outstanding EMI shielding effictiveness of 60 dB and efficient electro-/photothermal heating performance. Silicone encapsulation further imparts high hydrophobicity and exceptional durability against solutions and deformations to the multifunctional films. Impressively, the silicone-coated TM/BC film (Si-TM/BC) exhibits desirable low voltage-driven Joule heating and excellent photoresponsive heating performance, which demonstrates great feasibility for efficient thermal deicing under actual conditions. Therefore, we believe that the Si-TM/BC film with excellent mechanical properties and durability holds great promise for the practical applications of EMI shielding and ice accretion elimination.
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CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Zhiwei Yang,Lang Qiu,Mengke Zhang,Yanjun Zhong,Benhe Zhong,Yang Song,Gongke Wang,Yuxia Liu,Zhenguo Wu,Xiaodong Guo
SiO 2 is one of the critical raw materials for preparing Si anode. The direct use of porous Si made from SiO 2 in LIBs is challenging. Although carbon cladding can improve the cycling performance of Si anode materials made from SiO 2 , the surface coating cannot address the comminution inside the material during repeated volume deformation. For the first time, we prepared an in-situ doped Si/carbon anode material that uses SiO 2 and CO 2 as Si and carbon sources and Mg as the reduction medium (Mg 2 Si + CO 2 → MgO + Si + C). The in situ embedded carbon completes the nanosizing of Si (less than50 nm) and forms a three-dimensional (3-D) carbon network that enhances electrical conductivity and acts as a buffer layer. After 500 cycles at 0.5 A g −1 , the discharge specific capacity is 912 mAh g −1 , and the capacity still has 1487 mAh g −1 even at 4 A g −1 . The simple method of preparing Si/carbon composite material in situ provides a new idea for modifying Si-based anode material and provides a valuable reference for carbon doping.
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INORGANIC CHEMISTRY
·
2021
·
IF 5.165
Peng Zhang,Shen-Jing Ji,Dong Zhang,Huai-Guo Xue,Nian-Tzu Suen
Recently, it has been reported that the enstatite chondrite (EC) meteorite may contain enough hydrogen to provide a plausible explanation for water’s initial existence on Earth. Perryite mineral is one of the key components of EC, but its detailed chemical composition and phase width remain elusive compared with other minerals found in EC. Therefore, we embark on a series of investigations of the synthesis, crystal structure, and electronic structure of the synthetic perryite mineral (NixFe1–x)8(TyP1–y)3 (T = Si and Ge; 1 ≥ x, y ≥ 0). Its crystal structures were established based on single-crystal and powder X-ray diffraction techniques. It is realized that its structural and phase stabilities are highly dependent on the nature of the doping element (i.e., Fe and Si). The inclusion of Si and Fe elements can greatly alter the bonding scheme near the Fermi level (Ef), which is vital to the phase stability and accounts for the chemical composition of the natural perryite mineral (quaternary compound) in EC meteorites. Furthermore, this phase exhibits good electrocatalytic activity toward the hydrogen evolution reaction (HER). The best and the worst HER performances are for the Ni8Ge2P and Ni8Si2P samples, respectively, which suggests that the long bond length and high polarity of the covalent bond are the preferred criteria to enhance the electrocatalytic HER in this series.
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CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Haitang Yang,Yanping Yang,Xueqiang Cao,Xiaozhong Huang,Yang Li
A Yb 2 SiO 5 /mullite/Si tri-layer environmental-barrier-coating (EBC) were coated on SiC f /SiC substrates via Air Plasma Spraying (APS). The thermal cycle tests (TCT) were conducted under thermal corrosive condition of vapor-oxygen (50 vol% H 2 O and 50 vol% O 2 ) with thermal shock from 1200 °C to 200 °C. Microstructures, weight loss and bonding strength of the samples were systemically investigated after 101, 396, 606 and 700 TCT cycles respectively. The results show that the corner of the tri-layer coating peel off from the sample with weight loss of 1.3% after 700 TCT cycles. The bonding strength between substrate and tri-layer coatings gradually decreases to 6.79 MPa (approximately 55.2% of virgin specimens) after 700 cycles due to thermal shock induced cracks distributed horizontally within Si layers and between Si layer and outer layers.
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JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2021
·
IF 8.067
Sainan Liu,Hongtai Shen,Jiawei Xu,Xiaojun Zhou,Jianfei Liu,Zhenyang Cai,Xiaojun Zhao,Lairong Xiao
To develop an ultra-high-temperature resistant coating for a reusable thermal protection system, the preparation of a tantalum-based MoSi 2 -Mo coating by a new two-step process of multi-arc ion plating and halide activated pack cementation is presented. The coating has a dense structure and is well compatible with the tantalum substrate, which can be thermally shocked from room temperature to 1750 °C for 360 cycles without failure. The mechanism of the coating’s excellent resistance to high-temperature thermal shocks is that a strong-binding gradient interface and a dense SiO 2 oxide scale with good oxygen resistance are formed by the high-temperature self-diffusion of Si.
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