In-situ PECVD-enabled graphene-V₂O₃ hybrid host for lithium–sulfur batteries

Song, Yingze,Zhao, Wen,Wei, Nan,Zhang, Li,Ding, Feng,Liu, Zhongfan,Sun, Jingyu Elsevier 2018 Nano energy Vol.53 No.-

<P><B>Abstract</B></P> <P>Lithium–sulfur (Li–S) batteries have been regarded as promising candidates for current energy-storage technologies due to their remarkable advantages in energy density and theoretical capacity. However, one of the daunting challenges remained for advanced Li–S systems thus far deals with the synchronous suppression of polysulfide (LiPS) shuttle and acceleration of redox kinetics. Herein, a cooperative interface bridging adsorptive V<SUB>2</SUB>O<SUB>3</SUB> and conductive graphene is constructed <I>in-situ</I> by virtue of direct plasma-enhanced chemical vapor deposition (PECVD), resulting in the design of a novel V<SUB>2</SUB>O<SUB>3</SUB>-graphene hybrid host to synergize the LiPS entrapment and conversion. The redox kinetics and electrochemical performances of thus-derived cathodes were accordingly enhanced owing to the smooth adsorption-diffusion-conversion of LiPSs even at a sulfur mass loading of 3.7 mg cm<SUP>–2</SUP>. Such interfacial engineering offers us a valuable opportunity to gain insight into the comprehensive regulation of LiPS anchoring ability, electrical conductivity and ion diffusive capability in hybrid hosts on suppressing the LiPS shuttle and propelling the redox kinetics. Our devised PECVD route might pave a new route toward the facial and economic design of hetero-phased multi-functional hosts for high-performance Li–S systems.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Graphene-V<SUB>2</SUB>O<SUB>3</SUB> hybrid host was designed <I>in-situ</I> based on PECVD route. </LI> <LI> Thus-derived cathode showed a low capacity decay of merely 0.046% per cycle at 2 C after 1000 cycles. </LI> <LI> Cathodes with a relatively high sulfur mass loading (3.7 mg cm<SUP>–2</SUP>) were fabricated. </LI> <LI> The smooth adsorption-diffusion-conversion of polysulfides was thoroughly probed <I>via</I> experimental studies and DFT simulations. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Improved lithium storage performance of CeO2-decorated SrLi2Ti6O14 material as an anode for Li-ion battery

Ying Li,Hong-Yan Liu,Ling-Na Shi,Yan-Rong Zhu,Ting-Feng Yi 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.101 No.-

In this work, the CeO2-decorated SrLi2Ti6O14 anode was successfully prepared through a solid-state process. The space-charge effect induced by the internal adsorption of ions on the CeO2 surface can easilyresult in a formation of an excellent conductive interfacial layer between CeO2 and SrLi2Ti6O14. The goodelectrical contact between CeO2 and SrLi2Ti6O14 offers more active sites for the electrolyte storage andredox reaction, and promotes the intercalation/deintercalation of lithium ions, and thus improves therate performance and cycle stability. Due to its unique structure and composition, the CeO2-decoratedSrLi2Ti6O14 composites exhibit high reversible capacities, good cycle performance and outstanding rateperformance. Especially, the CeO2 (5 wt%)-decorated SrLi2Ti6O14 anode shows the most excellent electrochemicalperformance, which delivers a large charge capacity of 121.3 mAh g 1 and a capacity retentionof 94.48% after 100 cycles at 0.5 A g 1. However, the corresponding charge capacity and capacity retentionof pristine SrLi2Ti6O14 are 100.5 mAh g 1 and 86.77%, respectively. The CeO2(5 wt%)-decoratedSrLi2Ti6O14 with enhanced rate capacity, cycle stability and structural stability is a potential electrodematerial candidate for Li-ion battery.

Synchronous immobilization and conversion of polysulfides on a VO₂-VN binary host targeting high sulfur load Li-S batteries

Song, Yingze,Zhao, Wen,Kong, Long,Zhang, Li,Zhu, Xingyu,Shao, Yuanlong,Ding, Feng,Zhang, Qiang,Sun, Jingyu,Liu, Zhongfan The Royal Society of Chemistry 2018 ENERGY AND ENVIRONMENTAL SCIENCE Vol.11 No.9

<P>Lithium-sulfur (Li-S) batteries are deemed as one of the most promising next-generation energy storage systems. However, their practical application is hindered by existing drawbacks such as poor cycling life and low Coulombic efficiency due to the shuttle effect of lithium polysulfides (LiPSs). We herein present an <I>in situ</I> constructed VO2-VN binary host which combines the merits of ultrafast anchoring (VO2) with electronic conducting (VN) to accomplish smooth immobilization-diffusion-conversion of LiPSs. Such synchronous advantages have effectively alleviated the polysulfide shuttling, promoted the redox kinetics, and hence improved the electrochemical performance of Li-S batteries. As a result, the sulfur cathode based on the VO2-VN/graphene host exhibited an impressive rate capability with ∼1105 and 935 mA h g<SUP>−1</SUP> at 1C and 2C, respectively, and maintained long-term cyclability with a low capacity decay of 0.06% per cycle within 800 cycles at 2C. More remarkably, favorable cyclic stability can be attained with a high sulfur loading (13.2 mg cm<SUP>−2</SUP>). Even at an elevated temperature (50 °C), the cathodes still delivered superior rate capacity. Our work emphasizes the importance of immobilization-diffusion-conversion of LiPSs toward the rational design of high-load and long-life Li-S batteries.</P>

Synthesis and Characterization of Cobalt-Doped WS ₂ Nanorods for Lithium Battery Applications

Wang, Shiquan,Li, Guohua,Du, Guodong,Li, Li,Jiang, Xueya,Feng, Chuanqi,Guo, Zaiping,Kim, Seungjoo Springer 2010 NANOSCALE RESEARCH LETTERS Vol.5 No.8

<P>Cobalt-doped tungsten disulfide nanorods were synthesized by an approach involving exfoliation, intercalation, and the hydrothermal process, using commercial WS<SUB>2</SUB> powder as the precursor and <I>n</I>-butyllithium as the exfoliating reagent. XRD results indicate that the crystal phase of the sample is 2H-WS<SUB>2</SUB>. TEM images show that the sample consists of bamboo-like nanorods with a diameter of around 20 nm and a length of about 200 nm. The Co-doped WS<SUB>2</SUB> nanorods exhibit the reversible capacity of 568 mAh g<SUP>−1</SUP> in a voltage range of 0.01–3.0 V versus Li/Li<SUP>+</SUP>. As an electrode material for the lithium battery, the Co-doped WS<SUB>2</SUB> nanorods show enhanced charge capacity and cycling stability compared with the raw WS<SUB>2</SUB> powder.</P>

Vanadium Dioxide-Graphene Composite with Ultrafast Anchoring Behavior of Polysulfides for Lithium-Sulfur Batteries

Song, Yingze,Zhao, Wen,Zhu, Xingyu,Zhang, Li,Li, Qiucheng,Ding, Feng,Liu, Zhongfan,Sun, Jingyu American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.18

<P>The lithium-sulfur (Li-S) battery has been deemed as one of the most promising energy-storage systems owing to its high energy density, low cost, and environmental benignancy. However, the capacity decay and kinetic sluggishness stemming from polysulfide shuttle effects have by far posed a great challenge to practical performance. We herein demonstrate the employment of low-cost, wet-chemistry-derived VO<SUB>2</SUB> nanobelts as the effective host additives for the graphene-based sulfur cathode. The VO<SUB>2</SUB> nanobelts displayed an ultrafast anchoring behavior of polysulfides, managing to completely decolor the polysulfide solution in 50 s. Such a fast and strong anchoring ability of VO<SUB>2</SUB> was further investigated and verified by experimental and theoretical investigations. Benefitting from the synergistic effect exerted by VO<SUB>2</SUB> in terms of chemical confinement and catalytic conversion of polysulfides, the Li-S batteries incorporating VO<SUB>2</SUB> and graphene manifested excellent cycling and rate performances. Notably, the batteries delivered an initial discharge capacity of 1405 mAh g<SUP>-1</SUP> when cycling at 0.2 C, showed an advanced rate performance of ∼830 mAh g<SUP>-1</SUP> at 2 C, and maintained a stable cycling performance at high current densities of 1, 2, and 5 C over 200 cycles, paving a practical route toward cost-effective and environmentally benign cathode design for high-energy Li-S batteries.</P> [FIG OMISSION]</BR>

Carbon-coated SnO₂@C with hierarchically porous structures and graphite layers inside for a high-performance lithium-ion battery

Li, Yao,Zhu, Shenmin,Liu, Qinglei,Gu, Jiajun,Guo, Zaiping,Chen, Zhixin,Feng, Chuanliang,Zhang, Di,Moon, Won-Jin The Royal Society of Chemistry 2012 Journal of materials chemistry Vol.22 No.6

<P>A high-performance anode material was prepared from a hierarchically structured activated carbon which contains <I>in situ</I> graphene and nano-graphite. The activated carbon was immersed in a solution of SnCl<SUB>2</SUB>·2H<SUB>2</SUB>O and subjected to ultrasound. As a result, nanoparticles of SnO<SUB>2</SUB> were uniformly deposited on the surface of the activated carbon. The composite material was then coated with a thin layer of carbon by soaking it in a sucrose solution, followed by carbonization of the adsorbed sucrose at 500 °C. The resulting composite showed an outstanding high-rate cycling performance that can deliver an initial discharge capacity of 1417 mAh g<SUP>−1</SUP> and maintain a discharge capacity of more than 400 mAh g<SUP>−1</SUP> after 100 cycles at a high current density of 1000 mA g<SUP>−1</SUP>. This outstanding electrochemical performance is likely to be related to a unique combination of the excellent electrical conductivity of the activated carbon with graphite layers formed inside, its hierarchical pore structure which enhances lithium-ion transportation, and the carbon coating which alleviates the effects of volume changes, shortens the distance for Li<SUP>+</SUP> diffusion, facilitates the transmission of electrons, and keeps the structure stable.</P> <P>Graphic Abstract</P><P>Carbon-coated SnO<SUB>2</SUB>@C nanocomposite with hierarchically porous structures and graphite layers inside was prepared by ultrasound and hydrothermal treatment, which showed an outstanding high-rate cycling performance for lithium-ion battery. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c1jm14290a'> </P>

Optimization model and algorithm of thetrajectory of horizontal well with perturbation

An Li,Enmin Feng 한국전산응용수학회 2006 Journal of applied mathematics & informatics Vol.20 No.1-2

Identification and characterization of heat shock proteins in a parasitic wasp Chouioia cuneae (Hymenoptera: Eulophidae)

Li‐Na Pan,Feng-ZhuWANG,Xin-Yue ZHANG,Yan-Ni ZHAO,Geng-Ping ZHU,Min LI 한국곤충학회 2018 Entomological Research Vol.48 No.3

Heat shock proteins (HSPs) are known to be induced in response to various stress factors. Although HSPs have been studied in a number of insects, not much is known about HSPs in the natural enemies of insects, especially parasitoids. In this study, we identified and characterized five full‐length HSP genes (Cchsp40, Cchsp60, Cchsp70, Cchsp83, and Cchsp90) from an endoparasitic chalcid wasp, Chouioia cunea, which parasitizes the fall webworm, Hyphantria cunea pupae, a worldwide pest. The expression of Cchsps in response to temperature, pesticide stresses and UV radiation were also investigated by quantitative real‐time polymerase chain reaction (RT‐qPCR). The results showed that all five Cchsps were induced in response to hot and cold temperatures. Four pesticides induced the abundant expression of Cchsp70, Cchsp83 and Cchsp90 while ultraviolet radiation up‐regulated Cchsp40, Cchsp70, Cchsp83 and Cchsp90. These results indicate the different transcriptional profiles of the five different Cchsps in response to various abiotic stresses. The findings of this study provide insights into the response of C. cunea to abiotic stresses and insight into the use of this parasitoid in biological control strategies.

Intragranular and Intergranular Crack Propagation in Nanocrystalline Ni Under Single-Cycle Mode I Loading

Yan Feng,Jie Li,Xinhua Yang 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

As the first step to study the fatigue crack propagation, the molecular simulations were performed to investigate theopening, propagation and closure behaviors of intragranular and intergranular cracks in nanocrystalline Ni under single-cyclemode I loading. The atomic crack angle was proposed to characterize the crack-tip blunting and sharpening quantitatively. There are obvious different mechanisms between intragranular and intergranular crack propagation. Intragranular crack propagationcould be induced by stacking faults and can change its direction very easily, but the intergranular crack perpendicularto the loading direction would propagate along the grain boundary and encounter strong resistance at the triple junction. New cracks could form in the grain boundaries ahead of the original crack. Different from the traditional understanding forintragranular and intergranular cracks, however, the dislocation density increases even in the unloading process and the cracktip is possibly sharpened temporarily during loading.

Wrinkled rGO Sheets-Wrapped Carbon Fibers with High Tensile Strength and Excellent Electrochemical Stability as Anodes for Structural Li-Ion Battery

Huagen Li,Shubin Wang,Mengjie Feng,Jiping Yang,Boming Zhang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.08

Herein, we report a hierarchical structure formed by wrinkled reduced graphene oxide (rGO) sheets-wrapped carbon fiber via a facile and efficient electrostatic self-assembly method and subsequent annealing treatment. For this material, the Weibull scale parameter is 4.77 GPa. After 100 cycles, the rGO@CF retains 91% of its second charge capacity at 50mA· g -1, corresponding to a capacity fading of only 0.09% per cycle. Thus, this structural anode material exhibits enhanced capacity, high initial Coulombic efficiency and high tensile strength. Meanwhile, the carbon fiber and interweaved rGO sheets together form the whole conductive networks to provide multichannel highways for charge transfer (lithium-ion diffusion and electron transport) during discharge–charge processes, promising excellent electrochemical performance of this structural anode material.