A polymeric composite protective layer for stable Li metal anodes

Guo Suogang,Wang Li,Jin Yuhong,Piao Nan,Chen Zonghai,Tian Guangyu,Li Jiangang,Zhao Chenchen,He Xiangming 나노기술연구협의회 2020 Nano Convergence Vol.7 No.21

Lithium (Li) metal is a promising anode for high-performance secondary lithium batteries with high energy density due to its highest theoretical specific capacity and lowest electrochemical potential among anode materials. However, the dendritic growth and detrimental reactions with electrolyte during Li plating raise safety concerns and lead to premature failure. Herein, we report that a homogeneous nanocomposite protective layer, prepared by uniformly dispersing ­AlPO 4 nanoparticles into the vinylidene fluoride-co-hexafluoropropylene matrix, can effectively prevent dendrite growth and lead to superior cycling performance due to synergistic influence of homogeneous Li plating and electronic insulation of polymeric layer. The results reveal that the protected Li anode is able to sustain repeated Li plating/stripping for > 750 cycles under a high current density of 3 mA cm −2 and a renders a practical specific capacity of 2 mAh cm −2 . Moreover, full-cell Li-ion battery is constructed by using ­LiFePO 4 and protected Li as a cathode and anode, respectively, rendering a stable capacity after 400 charge/discharge cycles. The current work presents a promising approach to stabilize Li metal anodes for next-generation Li secondary batteries.

Effect of Heat Treatment on Microstructure and Mechanical Properties of Mg-10Li-3Al-3Zn-0.22Si Alloy

Yazhao Shen,Defu Li,Shengli Guo,Jiangtao Guo 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.10

The microstructure evolution and mechanical properties of as-extruded Mg-10Li-3Al-3Zn-0.22Si during heat treatment from473 to 673 K were investigated in this paper, and then the strengthening mechanism and fracture behavior of the studied alloywas also analyzed. Experimental results show that the matrix of as-extruded Mg-10Li-3Al-3Zn-0.22Si alloy mainly consistsof α-Mg and β-Li, and dispersive granular phases are AlLi and Li2MgAl. Mg2Siphase shows banded distribution alongextrusion direction. The morphology of α-Mg is from long strip to nearly spherical block at 573 K. The α-Mg reprecipitatesfrom β-Li matrix in the orientation relationship: (0001) α-Mg // (110) β-Li, [11 −2 0] α-Mg // [1 −1 0] β-Li at 623 K. While theAl-rich granular phase is decomposed and dissolve into the gradually, and then AlLi increase again at 673 K, which may becaused by the dissolution at high temperature and precipitation during air cooling in heat treatment. Besides, the solid solutionand dispersion strengthening enhances the strength of alloy after heat treatment. After heat-treated at 573 K for 1 h and thenair cooling, alloy presents excellent mechanical properties with the ultimate tensile strength of 253 ± 3 MPa and elongationof 27 ± 3%, respectively. Compared with the extruded state, ultimate tensile strength of alloy can be increased by about 49%.

The effect of S-functionalized and vacancies on V2C MXenes as anode materials for Na-ion and Li-ion batteries

Ya-Meng Li,Yong-Liang Guo,Zhao-Yong Jiao 한국물리학회 2020 Current Applied Physics Vol.20 No.2

The electrochemical properties of V2C and V2CT2 (T = O, S) MXenes with and without vacancy as anode materials for Na-ion and Li-ion batteries, have been studied using first-principles calculation. The present results indicate that the adsorption strength of Li-ion and Na-ion on V2CS2 are less than that of O-functionalized, together with a lower diffusion barrier. Simultaneously, V2CS2 monolayer exhibits lower open-circuit voltage (OCV) values of 0.72 and 0.49 V for Li- and Na-ion, respectively. Interestingly, the presence of atomic vanadium vacancy on V2CS2 monolayer exerts more prominent effects on enhancing adsorption strength than that of carbon vacancy for Li-ion and Na-ion, but with an exception for the diffusion of Li-ion and Na-ion on V2CS2 monolayer. The finding suggests that the V2CS2 monolayer is expected to be a potential candidate as anode material for Li-ion and Na-ion battery due to its lower open-circuit voltages and diffusion barriers.

Microstructure Evolution and Mechanical Properties of AA2099 Al–Li Alloy with Tailored Li‐Containing Precipitates in Uniaxial Compression at Medium Temperature

Li Hu,Mengdi Li,Weijiu Huang,Xusheng Yang,Fei Guo,Haipeng Dong 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.5

Microstructure characteristics and mechanical behavior of AA2099 Al–Li alloy with no pre-existing Li-containing precipitates(AA2099-1 sample), pre-existing δ′ precipitates (AA2099-2 sample), pre-existing T1phase (AA2099-3 sample) andpre-existing T2phase (AA2099-4 sample) are systematically investigated via isothermal uniaxial compression at 250 °C inthe present study. Experimental results demonstrate that at the onset of plastic deformation, dynamic precipitation of smallsizedT1phase occurs rapidly within AA2099-1 sample, while it will be hindered within AA2099-2 sample. The increasingplastic strain benefits to dynamic precipitation of small-sized T1phase in AA2099-2 sample. Consequently, AA2099-1 andAA2099-2 samples possess similar and intermediate mechanical behaviors. In terms of AA2099-3 sample, the existence oflarge-sized T1phase results in the maximum yielding stress. However, some regions within these large-sized T1precipitatesare suspected to be sheared by cross-slip, leading to the destruction of crystallographic structure and the formation of Almatrix intervals. This aspect is responsible for the gradual degradation in true stress-strain curve after peak stress. As forAA2099-4 sample, dynamic precipitation rarely happens during plastic deformation and the interaction between dislocationand the pre-existing T2phase belongs to Orowan looping, resulting in the minimal mechanical response. Besides,AA2099-1 sample possesses the average minimum deviation angle (MDA) of ~ 16.5° between the loading direction and the<110> crystal direction, whereas AA2099-4 sample owns the average MDA of ~ 7.5°. The difference in MDA is mainlyattributed to δ′ phase and T1phase, which will separately accelerate and postpone the rotation of orientation towards the<110> crystal direction.

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>

Antimony Selenide Nanorods Decorated on Reduced Graphene Oxide with Excellent Electrochemical Properties for Li-Ion Batteries

Wang, Xia,Wang, Hong,Li, Qiang,Li, Hongsen,Xu, Jie,Zhao, Guoxia,Li, Hongliang,Guo, Peizhi,Li, Shandong,Sun, Yang-kook The Electrochemical Society 2017 Journal of the Electrochemical Society Vol.164 No.13

<P>A promising anode material for lithium-ion batteries (LIBs) consisting of Sb2Se3 nanorods and reduced graphene oxide (rGO) sheets has been prepared by an effective solvothermal approach. The synergetic effect between Sb2Se3 nanorods and rGO matrix provides not only high conductivity paths and strong electron contact interface, but also alleviates the volume change of Sb2Se3 nanorods, resulting in excellent lithium-storage performance. When tested as an anode material for LIBs, a high capacity of 868.30 mAh g(-1) can be retained after 100 cycles at 200 mA g(-1). Even at 2000 mA g(-1), a satisfactory capacity of 430.40 mAh g(-1) after long 550 cycles can be delivered. Ex situ X-ray diffraction study suggests that the Sb2Se3/rGO composite follows the combined Li+ intercalation, conversion reaction and alloying reaction mechanism. These features suggest the Sb2Se3/rGO composite a viable choice for application as an anode material in high-performance LIBs. (C) 2017 The Electrochemical Society. All rights reserved.</P>

Characteristics of isolated lactic acid bacteria and their effects on the silage quality

Siran Wang,Xianjun Yuan,Zhihao Dong,Junfeng Li,Gang Guo,Yunfeng Bai,Junyu Zhang,Tao Shao 아세아·태평양축산학회 2017 Animal Bioscience Vol.30 No.6

Objective: Four lactic acid bacteria (LAB) strains isolated from common vetch, tall fescue and perennial ryegrass on the Tibetan Plateau were characterized, and their effects on the fermentation quality of Italian ryegrass (Lolium multiflorum Lam.) silage were studied. Methods: The four isolated strains and one commercial inoculant (G, Lactobacillus plantarum MTD-1) were evaluated using the acid production ability test, morphological observation, Gram staining, physiological, biochemical and acid tolerance tests. The five LAB strains were added to Italian ryegrass for ensiling at three different temperatures (10°C, 15°C, and 25°C). Results: All isolated strains (LCG3, LTG7, I5, and LI3) could grow at 5°C to 20°C, pH 3.0 to 8.0 and NaCl (3.0%, 6.5%). Strains LCG3, LTG7, I5, and LI3 were identified as Lactobacillus plantarum, Pediococcus acidilactici, Lactobacillus paraplantarum, and Lactobacillus casei by sequencing 16S rDNA, respectively. All LAB inoculants significantly (p<0.05) increased lactic acid (LA) contents and ratios of lactic acid to acetic acid, and reduced pH and ammonia nitrogen/ total nitrogen (AN/TN) compared with uninoculated silages at various temperatures (10°C, 15°C, and 25°C). Compared to the commercial inoculant G, I5, and LI3 showed similar effects on improving the silage quality of Italian ryegrass at 10°C and 15°C, indicated by similar pH, LA content and AN/TN. Conclusion: All inoculants could improve the silage fermentation quality at various temperatures (10°C, 15°C, and 25°C). At the temperature of 10°C and 15°C, strain I5 and LI3 had similar effects with the commercial inoculant G on improving the silage quality of Italian ryegrass.

One new species and one new record species of Cerapteroceroides Ashmead (Hymenoptera: Encyrtidae) from China

Guo‐Hao Zu,Cheng-De LI 한국곤충학회 2017 Entomological Research Vol.47 No.5

Cerapteroceroides acutiscapus sp. nov. is described as new and Cerapteroceroides manaliensis Hayat and Khan, 2015 is first recorded from China.

AI 기술을 적용하여 동물 입양을 위한 새로운 서비스 디자인 생성

Guo,Haoyue,Zhang Muxin,Chen Xie,Li Yueyi,Liang Lan,Pan Young Hwan 한국서비스디자인학회 2020 한국서비스디자인학회 학술대회자료집 Vol.2020 No.-

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>