JOURNAL OF ALLOYS AND COMPOUNDS
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2014
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IF 2.726
Zhixiao Zhang,Chongjun Xu,Xianwu Du,Zili Li,Jilin Wang,Weihong Xing,Yuan Sheng,Weimin Wang,Zhengyi Fu
High-performance TiB 2 –SiC composites were fabricated with a new reaction system of B 4 C–TiC–Si by reactive hot pressing. The reaction process was controlled by the diffusion of boron atoms and hindered by the accumulated product layer of TiB 2 and C. The melting Si can offer another diffusion path for boron atoms, thereby promoting the reaction process. The Vickers hardness , flexural strength , and fracture toughness of the fabricated TiB 2 –SiC composites respectively reached 28.6 ± 0.6 GPa, 654 ± 49 MPa, and 6.8 ± 0.5 MPa m 1/2 . Both the intergranular fracture resulting from mismatch in thermal expansion coefficient between TiB 2 and SiC and the transgranular fracture resulting from the network structure of TiB 2 can enhance the fracture toughness of the TiB 2 –SiC composite.
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Nanoscale
·
2015
·Vol. 7
·期 17
·8023-8034
·
IF 7.394
Jing Wang,Meijuan Zhou,Guoqiang Tan,Shi Chen,Feng Wu,Jun Lu,Khalil Amine
Silicon monoxide, a promising silicon-based anode candidate for lithium-ion batteries, has recently attracted much attention for its high theoretical capacity, good cycle stability, low cost, and environmental benignity. Currently, the most critical challenge is to improve its low initial coulombic efficiency and significant volume changes during the charge–discharge processes. Herein, we report a binder-free monolithic electrode structure based on directly encapsulating micro-nano Si/SiOx particles into conjugated nitrogen-doped carbon frameworks to form monolithic, multi-core, cross-linking composite matrices. We utilize micro-nano Si/SiOx reduced by high-energy ball-milling SiO as active materials, and conjugated nitrogen-doped carbon formed by the pyrolysis of polyacrylonitrile both as binders and conductive agents. Owing to the high electrochemical activity of Si/SiOx and the good mechanical resiliency of conjugated nitrogen-doped carbon backbones, this specific composite structure enhances the utilization efficiency of SiO and accommodates its large volume expansion, as well as its good ionic and electronic conductivity. The annealed Si/SiOx/polyacrylonitrile composite electrode exhibits excellent electrochemical properties, including a high initial reversible capacity (2734 mA h g−1 with 75% coulombic efficiency), stable cycle performance (988 mA h g−1 after 100 cycles), and good rate capability (800 mA h g−1 at 1 A g−1 rate). Because the composite is naturally abundant and shows such excellent electrochemical performance, it is a promising anode candidate material for lithium-ion batteries. The binder-free monolithic architectural design also provides an effective way to prepare other monolithic electrode materials for advanced lithium-ion batteries.
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SURFACE & COATINGS TECHNOLOGY
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2017
·
IF 2.589
K.Q. Song,Z.C. Lu,M. Zhu,R.Z. Hu,M.Q. Zeng
Nanocomposite Al–Sn-based bearing alloys produced by mechanical alloying (MA) exhibit high hardness; however, their poor sintering density and ductility limit their wide spread application. Here, we present a strategy to produce a dual-scale structure in an Al–Sn–Si alloy consisting of coarse and ultrafine grains through a combination of conventional powder sintering and thermomechanical treatment . We found that severe deformation and the presence of an Al–Si eutectic mixture for sample induced abnormal grain growth of Al to create the dual-scale Al–Sn–Si alloy through annealing treatment. An optimum matching of ductility and strength , and optimum wear performance were achieved at annealing temperatures of 500 and 550 °C. Detailed investigation of the wear mechanism revealed that the combination of high strength and high ductility provided by the dual-scale structure is a key factor for the improvement of the wear properties.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Fang Di,Xin Gu,Yang Chu,Lixiang Li,Xin Geng,Chengguo Sun,Weimin Zhou,Han Zhang,Hongwei Zhao,Lin Tao,Guangshen Jiang,Xueyuan Zhang,Baigang An
Owing to highly theoretical capacity of 3579 mAh/g for lithium-ion storage at ambient temperature, silicon (Si) becomes a promising anode material of high-performance lithium-ion batteries (LIBs). However, the large volume change (∼300 %) during lithiation/delithiation and low conductivity of Si are challenging the commercial developments of LIBs with Si anode . Herein, a sandwich structure anode that Si nanoparticles sandwiched between carbon nanotube (CNT) and silicon carbide (SiC) has been successfully constructed by acetylene chemical vapor deposition and magnesiothermic reduction reaction technology. The SiC acts as a stiff layer to inhibit the volumetric stress from Si and the inner graphited CNT plays as the matrix to cushion the volumetric stress and as the conductor to transfer electrons . Moreover, the combination of SiC and CNT can relax the surface stress of carbonaceous interface to synergistically prevent the integrated structure from the degradation to avoid the solid electrolyte interface (SEI) reorganization. In addition, the SiC (1 1 1) surface has a strong ability to adsorb fluoroethylene carbonate molecule to further stabilize the SEI. Consequently, the CNT/SiNPs/SiC anode can stably supply the capacity of 1127.2 mAh/g at 0.5 A/g with a 95.6 % capacity retention rate after 200 cycles and an excellent rate capability of 745.5 mAh/g at 4.0 A/g and 85.5 % capacity retention rate after 1000 cycles. The present study could give a guide to develop the functional Si anode through designing a multi-interface with heterostructures .
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GREEN CHEMISTRY
·
2024
·
IF 9.3
Yuan Qiao,Ali Reza Kamali
Porous structures, such as prous Si electrodes required for high-performance Li-ion batteries, are often produced through envirionmentally problematic processes. In this study, an innovative approach is employed for the green preparation of high-performance porous Si electrodes via thermal treatment of an electrode composed of Si nanoparticles, polyimide (PI), and nanostructured terephthalic acid (TPA). During the process, TPA sublimes at around 318 °C, resulting in a compact yet porous electrode, enhanced by cross-linked PI binder. Moreover, TPA can be regenerated through the condensation of vaporised monomers, supporting a circular economy for the clean preparation of the advanced electrode. Despite the simplicity of this method, the resulting electrode (Si@PI@nano-TPA@E-350) exhibits a remarkable Li-ion storage performance, demonstrating a reversible capacity of 2355 mAh g⁻¹ at 0.2 A g⁻¹ after 120 cycles, along with a reduced charge transfer resistance (Rct) of 99 Ω. This is in contrast to the electrode prepared without TPA (Si@PI@E-350), which only achieves a capacity of 1268 mAh g⁻¹. The morphological features of the TPA used significantly impact the electrode's performance. A full cell composed of Si@PI@nano-TPA@E-350 as the anode and LiFePO₄ as the cathode exhibits a reversible capacity of 151 mAh g⁻¹ relative to the total mass of the anode and cathode at 0.2 A g⁻¹ after 50 cycles, with a capacity retention of 97.8%, demonstrating an enhanced energy density of 455 Wh kg⁻¹. The article presents a green method for sustainably fabricating porous structures for efficient energy storage and a wide range of other applications.
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Journal of Energy Storage
·
2024
·
IF 8.9
Zhilong Wang,Zhongcheng Li,Yu Wang,Changjun Zhu,Kanghua Chen
Lithium metal anodes are an ideal candidate material for high energy density lithium-ion batteries. However, the uncontrollable growth of lithium dendrites and infinite volume expansion are a big challenge for the commercialization of lithium metal anodes. In order to realize dendrite-free lithium metal anodes, we prepared N-doped carbon/Si nanoparticles composite film modified Ni foam (NFSC) via a simple impregnation-calcination method as a three-dimensional (3D) lithiophilic skeleton for lithium metal anodes. NFSC has several advantages, including a 3D porous conductive structure, a large specific surface area, uniformly distributed abundant lithiophilic nitrogen-containing functional groups and Si nanoparticles providing abundant lithium nucleation sites. This reduces nucleation overpotential, facilitates uniform lithium deposition, suppresses the growth of lithium dendrites, and significantly improves the cycling stability of lithium metal anodes. As a result, NFSC exhibits low nucleation overpotential and the Li||NFSC half-cell maintains a high Coulombic efficiency (CE) of 99.15 % after 1000 cycles at 1 mA cm −2 and 1 mAh cm −2 . Moreover, the NFSC in a symmetric cell exhibits low polarization voltage of 18 mV together with an ultra-long cycling life of over 2000 h at 1 mA cm −2 and 1 mAh cm −2 . Furthermore, the full cell assembled with LiFePO 4 and NFSC@Li demonstrates superior rate performance and excellent long-term cycling stability. The long-term cycling stability exceeds 2500 cycles at 0.5C, far surpassing that of LiFePO 4 ||Li full cell (600 cycles). This work provides a simple and effective approach to achieve dendrite-free lithium metal anodes.
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ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Yupeng Xiao,Xiaoqian Hao,Tianle Li,Yangyang Mao,Tianjiao Zhu,Jinqi Zang,Yuqian Li,Wenju Wang
The intrinsic volumetric stress during cycling is the main obstacle for developing Si-based materials as high-energy-density lithium-ion battery anodes. Elastic binders have been demonstrated as an efficient approach to alleviate the stress of Si. Herein, we design a tough 3D hard/soft polymeric network (LPTS) using lithiated poly(acrylic acid), silk sericin, and highly branched tannic acid. Covalent cross-linking provides a robust mechanical strength to endure the large stress. The formed multiple hydrogen bonds with bonding energies between 3.46 and 25 kcal mol–1 can effectively dissipate the stress through sequential hydrogen bond disassociation. The multifunctional LPTS binder maintains the integrity of the Si-based electrodes during repeated discharging/charging. Additionally, Li+ can be transferred via a Li-conducting group (−COOLi), thereby enhancing the ionic conductivity of electrodes. Consequently, the Si/LPTS electrode exhibits an improved initial Coulombic efficiency and excellent durability over 400 cycles. Meanwhile, this binder is also suitable for Si–C anodes, enabling stable cycling at a high areal capacity >3.6 mAh cm–2 and delivering 72.2% capacity retention for the LFP||Si–C/LPTS full cell after 200 cycles. This study provides insight into developing efficient Si-based binders that are facile and low-cost for next-generation high-energy-density systems.
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ACS Catalysis
·
2017
·
IF 10.614
Meng Liu,Song Shi,Li Zhao,Min Wang,Guozhi Zhu,Xi Zheng,Jin Gao,Jie Xu
A core–shell catalyst (Co–SiO2@Ti–Si) with cobalt-based SiO2 nanocomposite (Co–SiO2) as the core and Ti-doped mesoporous silica as the shell was designed to catalyze a one-pot reaction of sulfide oxidation with in situ generated hydroperoxide. The catalyst was characterized by SEM, TEM, UV–vis spectroscopy, and XPS, among other methods. Compared to Co–SiO2 and the physical mixture of the two components (Co–SiO2 + Ti–Si), the core–shell catalyst significantly enhanced the reaction rate of the sulfide oxidation. The utilization efficiency of the hydroperoxide was an important factor responsible for the differences in the reaction rates. A further mechanism study showed that the improvement of the efficiency was due to the existence of a coordination pathway. The core–shell structure of a bifunctional catalyst represents a strategy for improving the utilization efficiency of hydroperoxide.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2024
·
IF 5.8
Yutai Wang,Qunyi Wang,Xiaoyan Zhou,Puguang Ji,Gongkai Wang,Chengwei Zhang,Mengxiao Sun,Mirtemir Shodievich
Because of the unique ability to combine high energy density with high power density, lithium-ion hybrid capacitors (LICs) have generated significant interest. Among the various anodes being explored for LICs, silicon (Si) stands out as a particularly promising anode material due to its high theoretical capacity. Nevertheless, the formidable challenge lies in the rapid capacity fade resulting from substantial volume expansion. Herein, a simple and efficient spray drying technique was used to fabricate a Si@rGO@NC composite with micro-nano structure. In this composite, Si nanoparticles are encapsulated between reduced graphene oxides (rGO) hollow spheres and a layer of carbon is coated on the surface of both the Si and the micron-sized composite particles, forming a rigid and mechanically stable structure. The composite combines the high activity of nano-Si with the industrially easy handling of micron-scale particles. Moreover, the rGO hollow spheres not only enhance the electrical conductivity but also buffer the volume expansion of the electrode and provide channels for the rapid transport of electrolyte/ions. Thanks to its advantageous structural features, the constructed LICs with activated carbon as cathode can achieve a Max. energy/power density of 253.1 Wh kg −1 /10,824.1 W kg −1 and maintain 84.3 % of its initial capacitance after 8000 cycles. The micro-nano structured design concept of Si-based materials developed in our work could offer new insights and directions for the future development of Si-based energy storage devices.
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RSC Advances
·
2024
·Vol. 14
·期 12
·8204-8213
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IF 3.9
Fangli Li,Ziqin Huang,Changjiang Liu,Meini Yang,Jixiang Wu,Wenhui Rao,Chuanbai Yu
Currently, additively efficient flame retardants are being developed to enhance the smoke suppression, flame retardancy, and thermal properties of composite materials. To this end, the current study designed and prepared a novel P/N/Si/Zn-containing organic–inorganic hybrid denoted as APHZ. Its inorganic part was 2-methylimidazole zinc salt (ZIF-8), which improved its smoke suppression and catalytic carbonization. The organic part (P/N/Si-containing compound) promoted its flame retardancy and interfacial compatibility between APHZ and epoxy resin (EP). The test results revealed that EP/APHZ-3 composites achieved a V-0 rating and a notable LOI value of 30.7% when introducing 3 wt% APHZ into the EP matrix. Cone calorimetry tests (CCT) further demonstrated that the average heat release rate (av-HRR), total smoke production (TSP), and CO production (COP) of EP/APHZ-3 were reduced by 23.3%, 14.0%, and 21.1%, respectively. Meanwhile, the char residual was increased by 60.6%, as compared to pure EP. Furthermore, the flame-retardant mechanism of EP/APHZ composites was investigated by the XPS, TG-FTIR, and Raman spectroscopy techniques. The observed synergistic effect of the imidazole skeleton ZIF-8 and P/N/Si-containing compound in APHZ facilitated the generation of a dense multi-element char layer, with the condensed phase flame-retardant mechanism playing a dominant role. These findings contribute to developing and designing high-performance flame-retardant EP.
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CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Yong Tang,Xiyu Zhang,Zheng Liu,Xiaoya Liu,Xiaojie Li
Epoxy resin is renowned for its admirable comprehensive properties, but its inherent brittleness and poor fire safety severely limit its practical application in high-tech fields. Therefore, improving the fire safety and toughness of epoxy thermosets while maintaining their strength and thermal stability is both urgent and challenging. In this study, a novel hyperbranched polymer (HBPDR-DPP) has been synthesized via a one-pot, two-step process using dichlorodiphenylsilane, resveratrol, and diphenylphosphinic chloride. This polymer was then incorporated into high-performance epoxy thermosets. The resulting thermoset, containing 4 wt% HBPDR-DPP, exhibited an impressive limiting oxygen index (LOI) of 30.2 %, along with a 26.0 % decrease in peak heat release rate (PHRR) and a 10.9 % reduction in total smoke production (TSP) compared to the unmodified epoxy thermoset. These notable improvements can be primarily attributed to the synergistic carbonization effects of the silicon- and phosphorus-containing segments in HBPDR-DPP. Meanwhile, the 4 wt% HBPDR-DPP-modified epoxy thermoset exhibited significant improvements in mechanical properties, with tensile strength, flexural strength, and impact strength increasing by 37.8 %, 54.6 %, and 83.4 %, respectively. These enhancements can be attributed to the hyperbranched structure and the combination of rigid aromatic units with flexible Si-O chains in HBPDR-DPP. Moreover, the EP/HBPDR-DPP thermoset demonstrated excellent thermal stability. This study presents a simple and effective strategy for enhancing both the fire safety and mechanical properties of epoxy thermosets, offering valuable insights for the development of high-performance thermosetting materials.
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Coatings
·
2024
·Vol. 14
·期 9
·1210
·
IF 2.9
Songjia Kong,Chenguang Liu,Jiawei Ren,Tianchang Wang,Xianwei Geng,Yudan Yuan,Chun Zhao,Cezhou Zhao,Li Yang
Silicon is a promising anode material for high-performance lithium-ion batteries (LIBs), but its rapid capacity degradation has significantly hindered its large-scale application. In this study, we propose an in situ self-assembly polymerization method to fabricate a stable silicon-based anode by leveraging electrostatic self-assembly technology, in situ esterification, and amidation reactions. The incorporation of a cross-linked polymer, combined with the synergistic effects of electrostatic interactions between negatively charged MXene and positively charged silane-coupling-agent-modified silicon, offers a novel strategy for enhancing the electrochemical performance of LIBs. Notably, annealed electrodes with a 65 wt% nmSi-NH2/MXene ratio demonstrate outstanding electrochemical performance, achieving a capacity of 929.5 mAh g⁻¹ at a current density of 1 A g⁻¹ after 100 charge/discharge cycles. These findings suggest that the integration of cross-linked polymers and electrostatic self-assembly can significantly improve the intercalation and overall electrochemical performance of silicon anodes in lithium-ion batteries.
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