Nanoscale
·
2014
·Vol. 6
·期 21
·12532-12539
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IF 6.739
Xuejiao Feng,Jun Yang,Yitian Bie,Jiulin Wang,Yanna Nuli,Wei Lu
Nano/micro-structured pSi and pSi/CNT particles were synthesized from nano-SiO2 as both a template and silicon precursor via a combination of spray drying and magnesiothermic reduction, followed by a nano-layer carbon coating by chemical vapor deposition to obtain a nano/micro-structured pSi/C and pSi/CNT/C composite. In the hierarchical microstructure of the pSi/CNT/C composite, Si nanoparticles less than 20 nm in size were homogenously dispersed in an electronically conductive and porous network of multiwall carbon nanotubes, which can accommodate the volume changes in Si and improve the structural and conductive stability during repeated cycles leading to excellent electrochemical performance. The pSi/CNT/C presented reversible capacities of ca. 2100 mA h g−1 at 1 A g−1 and ca. 1370 mA h g−1 at a high current rate of 5 A g−1. Its capacity retention after 100 cycles was 95.5% at 1 A g−1.
研究领域:
材料科学
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能源科学
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2021
·
IF 7.312
Yun Guo,Hong-Yi Li,Jie Cheng,Shuo Shen,Jiang Diao,Bing Xie
The V-Cr-bearing reducing slag (VCBRS) is solid waste, which cannot be treated at present. This work proposes an effective approach to separately recover its major elements of V, Cr and Si and fully utilize the VCBRS with added-values. Flocculation desiliconization is used to extract Si from the acid solving liquid of VCBRS and Si is recovered as white carbon black with purity of 94.60% and recovery of 93.04%. After desiliconization, V in the solving liquid is selectively oxidized by H 2 O 2 and extracted by microemulsion extraction, which is recovered as V 2 O 5 whose purity is 99.60% with recovery at 96.32% from the stripping liquor of loaded microemulsion . Cr in the raffinate is recovered by alkaline precipitation as final product of Cr 2 O 3 with purity of 98.83% and recovery of 92.68%. The principles are discussed in detail and the operation conditions are optimized systematically. The microemulsion and wastewater are both cyclically utilized, which eliminates the secondary wastes. This work efficiently recovers all valuable elements with increased values from the solid waste, which can not only solve the environmental pollution problem, but also realize the efficient recovery of valuable elements to achieve comprehensive utilization.
研究领域:
冶金工程
·
环境科学
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Journal of Energy Storage
·
2025
·
IF 9.8
Changxu Yang,Jiahe Zhang,Shuo Zhang,Zhenyang Song,Duanyi Li,Chuqin Wang,Ke Wang,Jingang Liu
Si/C anode is regarded as a competitive candidate for next generation lithium-ion batteries due to its outstanding specific capacity. However, the practical application of Si/C anode is still obstructed by its significant volumetric variation during charging and discharging. Numerous studies have demonstrated that polyimide (PI) can effectively mitigate volumetric deformation. However, the majority of these investigations have predominantly utilized insoluble PI, whose high-temperature imidisation process would produce large internal stresses and holes that are detrimental to the performance of the battery. In this study, two types of soluble polyimides were synthesized and applied to Si/C anode: a fluorine- and silicon-containing variant and a fluorine- and amino-group-containing variant. Both PI-FS and PI-FN have relatively well bonding properties. Meanwhile, PI-FN, which introduces amino groups, has lower energy gap and better conductive ability. Compared with PVDF, the PI-based binder changes the component distribution of the solid electrolyte interface and significantly improves the cycling stability of the Si/C anode.
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RSC Advances
·
2015
·Vol. 5
·期 102
·83581-83587
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IF 3.84
Jinzhu Wu,Jun Dai,Yanbin Shao,Yanchun Sun
Novel fluorescent silicon quantum dots (Si-QDs) were synthesized by a one-step hydrothermal procedure using (3-aminopropyl)trimethoxysilane (APTES) as a silicon source and sodium ascorbate (SA) as a reducing agent. This synthetic strategy is straightforward, efficacious and low-cost. The as-synthesized Si-QDs featured narrow size distribution, intense purple-blue fluorescence with a photoluminescence quantum yield (PL QY) of 21%, complete water solubility, and favorable biocompatibility. Moreover, the resultant Si-QDs present robust stability in different circumstances, such as for long-term storage in air, in a wide pH range of 2–12 and under continuous UV irradiation, and they also do not respond to some metal ions. Their superior stability and safety render Si-QDs applicable as fluorescent probes in biomedical applications. The use of Si-QDs as an optical probe is illustrated by fluorescent imaging of IE8 cells.
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METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
·
2024
·Vol. 55
·期 3
·1385-1394
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IF 2.4
Zhang Liqi,Zhang Xu,Huang Bowen,Yang Yusheng,Zhao Zengwu
Silicon has been applied in many fields, such as high-purity semiconductors, high-temperature resistant materials, optical fiber connection materials, organosilicon compounds, and alloys. In this work, silicon was extracted from the Bayan Obo tailing by high-temperature electrolysis. The reduction process of Si(IV) and the effect of CaF 2 content on the reduction process were studied in the SiO 2 –CaO–CaF 2 melt. The Si(IV) ions in the SiO 2 –CaO system with 10 wt pct CaF 2 were reduced by a one-step four-electrons transfer process. In the SiO 2 –CaO melt with 15, 20, and 30 wt pct CaF 2 , the reduction process of Si(IV) was a two-step two-electrons transfer process: Si(IV) + 2e → Si(II) and Si(II) + 2e → Si(0). The reduction process of Si(IV) to Si(II) was reversible and was controlled by diffusion. The diffusion coefficient was 1.52 × 10 −8 cm 2 s −1 . Si and WSi 2 were prepared under a current density of − 0.55 A cm −2 at 1738 K. It was found that the WSi 2 alloys were formed because of the alloying of Si(IV) and W. Graphical
研究领域:
冶金学
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材料科学
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电化学
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无机化学
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高影响因子
Sustainable Energy & Fuels
·
2021
·Vol. 5
·期 23
·6170-6180
·
IF 6.367
Jijun Lu,Junhao Liu,Xuzhong Gong,Zhi Wang
Silicon is considered to be the most promising candidate for the anode of high energy density lithium-ion batteries. Nanometerization has been proven to be an effective method for improving the stress accumulation caused by the volume expansion of silicon. However, new issues such as poor initial coulombic efficiency (ICE) need to be solved because nanostructure silicon has an increased specific surface area. Here, a doping modification strategy is developed by a solvothermal combined with low-pressure gas–solid conversion reaction, and innovatively formed an Fe3C/N co-doped carbon coating on the nano-silicon surface. The doping of Fe3C in the composite material can catalyze the formation of a thin and stable solid electrolyte interphase (SEI) on the electrode surface and serve as a framework to stabilize the electrode structure during charge and discharge. As a result, Fe3C doping can significantly increase the ICE of the electrode from 66.4% to 87.1%, and the stable efficiency exhibited a rapid increase upwards of 99.5% after only 6 cycles including the first formation cycle, compared to the non-doped structure. The modified nano-silicon with Fe3C doping can provide high reversible capacity (1443.3 mA h g−1 after 200 cycles at 0.2 A g−1) and long cycle life (74% capacity retention after 1000 cycles at 0.5 A g−1).
研究领域:
材料科学
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能源存储
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JOURNAL OF SOLID STATE ELECTROCHEMISTRY
·
2017
·Vol. 21
·期 8
·2259-2267
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IF 2.316
Zhang Ju,Gu Jingwei,He Hongyan,Li Mingqi
To suppress the volume change of silicon and enhance the conductivity of the electrodes, nano-Si@SiO x @C composites with different carbon content are synthesized, in which nano-Si is embedded in SiO x matrix and coated by pyrolyzed C. Among the as-prepared composites, nano-Si@SiO x @22.45 wt%C exhibits the best comprehensive electrochemical performance, which delivers a first reversible capacity of 1184 mAh g −1 with capacity retention of 93% after 150 cycles at 100 mA g −1 . Moreover, it also shows good rate capability. The excellent electrochemical performance is attributed to the special structure and rational composition of the composite, in which the combination of a modest amount of coating carbon and SiO x matrix not only effectively mitigates the volume effect of nano-Si particles but also guarantees a high reversible capacity.
研究领域:
材料科学
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能源化学
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电化学
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纳米技术
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储能材料
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DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Junkai Zhao,Kaimeng Yang,Jianjun Wang,Daina Wei,Zhaoen Liu,Shiguo Zhang,Wen Ye,Ce Zhang,Zhaolong Wang,Xiaojing Yang
Anodes based on silicon/carbon composites promise their commercial prospects for next-generation lithium ion batteries owing to their merits of high specific capacity, enhanced ionic and electronic conductivity, and excellent compatibility. Herein, a series of carbonaceous framework/Si composites are designed and prepared by rational waste utilization. N, P codoped foam-like porous carbon/Si composites (FPC@Si) and N, P codoped carbon coated Si composites (NPC@Si) are fabricated by utilizing expired milk powder as a carbon source with facile treatment methods. The results indicate that the porous carbon skeleton and carbon shell can improve the conductivity of Si and stabilize the solid electrolyte interfaces to avoid direct contact between active material and electrolyte. Moreover, the influence of drastic volume expansion of Si on the anode can be efficiently alleviated during charge/discharge processes. Therefore, the Si/C composite electrodes present excellent long-term cycling stability and rate capability. The electrochemical performance shows that the reversible capacity of FPC@Si and NPC@Si can be respectively maintained at 587.3 and 731.2 mAh g −1 after 1000 charge/discharge cycles under 400 mA g −1 . Most significantly, the optimized Si/C composite electrodes exhibit outstanding performance in the full cell tests, promising them great potential for practical applications. This study not only provides a valuable guidance for recycling of waste resources, but also supports a rational design strategy of advanced composite materials for high-performance energy storage devices.
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Materials Today Sustainability
·
2022
·
IF 7.244
S. Zhang,X. Xu,J. Tu,F. Chen,J. Xie,T. Zhu,X. Zhao
Although silicon is regarded as the appealing anode for next-generation lithium-ion batteries (LIBs) due to its high specific capacity, its practical application is still hindered by large volume expansion upon lithiation. To tackle the issue, novel binders have been developed in recent years. Herein, we construct a three-dimensional cross-linked binder by forming hydrogen bonds between carboxymethyl cellulose (CMC) and ethylenediaminetetraacetic acid disodium (EDTA-2Na) with EDTA-2Na further coordinated to calcium ions (Ca 2+ ). Compared with the bare CMC binder, the cross-linked CMC/EDTA-Ca 2+ binder exhibits a better mechanical property and higher adhesion strength , which enables reversible volume change and improves the cycling performance of Si/C anode (80.7% retention after 380 cycles at 1 A g −1 ). Meanwhile, low-cost and abundant photovoltaic waste silicon was recycled as Si source to fabricate Si/C anode. This work provides a sustainable route to fabricate Si anode by recycling photovoltaic Si and a practical method to stabilize Si anode by constructing a cross-linked binder.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Haodong Li,Haoyu Li,Zhiwei Yang,Yizhu Lai,Qing Yang,Pengxin Duan,Zhuo Zheng,Yang Liu,Yan Sun,Benhe Zhong,Zhenguo Wu,Xiaodong Guo
The application value of silicon-based anodes has not been fully realized due to the ∼ 300% volume expansion and poor electronic conductivity. In present study, mesoporous Si/C (MP-Si/C) composite with nanosized primary particles of 30–50 nm and pore diameter of 20–40 nm was proposed, which displays superior Li storage properties. Firstly, Polyacrylic acid (PAA) was applied to fulfill in-situ carbon coating and inhibit the particle growth of SiO 2 generated from tetraethyl orthosilicate (TEOS) in stöber reaction. Secondly, Mg gas was introduced to create nano-sized Si with meso -pores and three-dimensional carbon network via the gas-cutting effect. The cycling stability and rate capability were both significantly enhanced with capacity of 671 mAh/g after 400 cycles and 593 mAh/g after 500 cycles at 2 A/g and 4 A/g, respectively, which was highly relevant to the selection of carbon source PAA and its corresponding carbon coating and Mg reduction effect. Moreover, this method bypasses the use of costly nano-silicon, which provides inspiration for the commercialization of silicon-based anodes.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Jiafeng Gao,Songlin Zuo,He Liu,Qiwen Jiang,Chenhao Wang,Huanhuan Yin,Ziqi Wang,Jie Wang
Silicon (Si) anode is the most promising alternative for next generation lithium-ion batteries (LIBs) owing to large theoretical capacity, low working voltage and abundant natural resources. However, tremendous volume change of Si during the (de)lithiation processes causes repetitive formation of solid electrolyte interphase (SEI) layers, loss of electrical contact and electrodes pulverization , limiting its commercial application. Herein, we fabricate an interconnected hollow Si-C nanospheres/graphite composite via a facile and scalable approach. Notably, hollow Si-C nanospheres and graphite are homogeneously combined by using the surfactants as surface modifiers of graphite and introducing carbon dioxide (CO 2 ) into magnesiothermic reduction reaction, resulting in the enhanced compatibility between hollow Si-C nanospheres and graphite, and the well-established electrical conductive network. The resultant Si-C nanospheres/graphite composite anode with carbon content of 59 wt% delivers a large reversible specific capacity of 662 mAh g −1 and a high capacity retention of 65.7% at 0.5 A g −1 after 200 cycles. Such excellent rate performance and superior cycling performance are attributed to high electrical conductivity and buffering effect of graphite, superior compatibility between hollow Si-C spheres and graphite, uniform distribution of both Si-C nanospheres with a unique hollow architecture and graphite flakes inside the composites and well-established interconnected electrical conductive carbon networks, which can effectively alleviate Si volume expansion and maintain good electrical contact during cycling. This strategy provides insights into designing Si-based anodes for practical LIBs.
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RSC Advances
·
2022
·Vol. 12
·期 22
·13756-13764
·
IF 4.036
Wang-Xi Fan,Zefang Li,Zhou Yang,Jun-Fei Ou,Meng Xiang,Zhong-Li Qin
Novel star-like molecules containing P, N and Si with dual functions of flame retardance and curing promotion (abridged as HCCP–KH540) were successfully synthesized through the nucleophilic substitution reaction of hexachlorocyclotriphosphazene (HCCP) and 3-aminopropyltrimethoxysilane (KH540). HCCP–KH540 was incorporated with the matrix of epoxy resin (EP) to form a flame retardant composite abridged as E-HK. The activation energy of the curing reaction of the E-HK composite was reduced but the curing reaction rate was accelerated by HCCP–KH540. The E-HK composite with 30 phr content of HCCP–KH540 exhibited excellent flame retardancy with limiting oxygen index of 29.6% and V-1 rating in the vertical burning test as well as excellent thermal stability with a char yield of 23.77% at 700 °C, compared with only 8.64% for pure EP.
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