Effect of Zn2+ and F- Co-Modification on the Structure and Electrochemical Performance of Li4Ti5O12 Anode Material

Aijia Wei,Wen Li,Lihui Zhang,Xiaohui Li,Xue Bai,Zhenfa Liu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.5

Zn2+ and F- ions are successfully used to modify pure Li4Ti5O12 via a co-precipitation method followed by calcination at 400℃ for 5 h in an Ar atmosphere in order to further investigate the reaction mechanism of the fluoride modification process. Zn2+ and F- co-modified Li4Ti5O12 samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and electrochemical measurements. After the modification process, no ZnF2 coating layer is formed on the surface of Li4Ti5O12, instead, F- ions react with Li4Ti5O12 to generate a new phase, composed of a small amount of anatase TiO2, rutile TiO2, LiF, and Zn2+ ions are suspected to form a ZnO coating layer on Li4Ti5O12 particles. The electrolyte reduction decomposition is suppressed in Zn2+ and F- co-modified Li4Ti5O12 due to the ZnO coating layer. 1 wt.% Zn2+ and F- co-modified Li4Ti5O12 exhibits the best rate capability, which leads to a charge capacity of 236.7, 227.8, 222.1, 202.7, 188.9 and 150.7 mAh g -1 at 0.2C, 0.5C, 1C, 3C, 5C and 10C, respectively, between 0 V and 3 V. Furthermore, 1 wt.% Zn2+ and F- comodified Li4Ti5O12 exhibits 96.0% charge capacity retention at 3C rate after 200 cycles, which is significantly higher than that of pure Li4Ti5O12 (78.4%).

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>

Membrane technologies for Li+/Mg2+ separation from salt-lake brines and seawater: A comprehensive review

Ye Zhang,Li Wang,Wei Sun,Yue-hua Hu,Honghu Tang 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.81 No.-

Recent years have seen rapid improvement of technology and large-scale applications of lithium-ionbatteries, which leads to an increasing market demand for lithium. Since the land lithium resources arediminishing drastically, the sources of lithium extraction have shifted to the large amount of waterresources containing salt-lake brines and seawater. Among the varieties of aqueous recovery approaches,membrane technology seems to have huge development potential and good application prospect. This isbecause the membrane technologies exhibit excellent Li/Mg separation selectivity, with low energyconsumption and green process owing to no addition of chemicals. The present work reviews the latestadvances in various membrane technologies, including nanofiltration membrane, electrodialysis,membrane capacitive deionization approaches, solid electrolyte electrolysis-based technology, etc. Therecent developments in positively charged nanofiltration membrane are discussed in terms of thepreparation methods, membrane properties, and Li/Mg separation coefficient. In addition, the effects ofseveral factors on electrodialysis for lithium extraction and relevant mechanisms in both simple andactual saline systems are discussed, including applied voltage, VC/VD, and coexisting ions. Theapplications of electrodialysis with novel selective membrane involving nanofiltration membrane as wellas solid electrolyte membrane and perspectives for further investigation are proposed.

Review on State of Charge Estimation Methods for Li-Ion Batteries

Xiaoqiang Zhang,Wei-ping Zhang,Hongyu Li,Mao Zhang 한국전기전자재료학회 2017 Transactions on Electrical and Electronic Material Vol.18 No.3

The state of charge (SOC) is an important parameter in a battery-management system (BMS), and is very significantfor accurately estimating the SOC of a battery. Li-ion batteries boast of excellent performance, and can only remainat their best working state by means of accurate SOC estimation that gives full play to their performances and raisestheir economic benefits. This paper summarizes some measures taken in SOC estimation, including the dischargeexperiment method, the ampere-hour integral method, the open circuit voltage method, the Kalman filter method,the neural network method, and electrochemical impedance spectroscopy (EIS. The principles of the various SOCestimation methods are introduced, and their advantages and disadvantages, as well as the working conditionsadopted during these methods, are discussed and analyzed.

Effect of Cooling Rate on Solidification and Segregation Characteristics of 904L Super Austenitic Stainless Steel

Yunong Li,Dening Zou,Wanwan Chen,Yingbo Zhang,Wei Zhang,Fanghong Xu 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8

To study and understand the solidification behavior of super austenitic stainless steel under different cooling rates and segregationlaws of alloying elements is of great significance to optimize the subsequent diffusion annealing homogenizationtreatment process and improve product quality. According to Thermo-Calc thermodynamic simulation results and combinedwith high temperature laser confocal scanning electron microscope (HT-CSLM), the tissue morphology of 904L superaustenitic stainless steel was observed in-situ during solidification. The solidification path of the test steel was determinedvia calculation with the Scheil-Gulliver model. Microscopy techniques, including true color microscopy, scanning electronmicroscopy (SEM), energy dispersive spectrometer (EDS), and electron probe microanalyzer (EPMA) were used to analyzethe influence of different cooling rates (6 ℃/min, 50 ℃/min, and 100 ℃/min) on the solidification structure and determine themain distribution law of alloying elements. This analysis determined that the solute distribution coefficient (K) of Cr, Mn,Mo, Cu, and Si elements is less than 1 during the solidification process, which means that they will accumulate in the liquidphase. Among them, elemental Mo segregation is the most severe, while elemental Ni hardly segregates. As the cooling rateincreases, the crystallization temperature of the test steel decreases, and the secondary dendrite arm spacing λ2 decreases,the concentration of Mo in the residual liquid phase increases.

Evolution of the effect of sulfur confinement in graphene-based porous carbons for use in Li-S batteries

Jia, Xiangling,Zhang, Chen,Liu, Juanjuan,Lv, Wei,Wang, Da-Wei,Tao, Ying,Li, Zhengjie,Zheng, Xiaoyu,Yu, Jong-Sung,Yang, Quan-Hong The Royal Society of Chemistry 2016 Nanoscale Vol.8 No.8

<P>A controllable drying strategy is proposed for the precise and non-destructive control over the structure of a 3D graphene assembly. Such an assembly is used as a model carbon material to investigate the pore structure-dependent shuttle effect and cycling performance of the cathode of a Li-S battery.</P>

Structure and Performances of xLiFePO4/C·(1 − x)Li3V2(PO4)3/C Cathode for Lithium-Ion Batteries by Using Poly(vinyl alcohol) as Carbon Source

Chang-ling Fan,Wei-hua Zhang,Tao-tao Zeng,Ling-fang Li,Xiang Zhang,Shao-chang Han 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.11

Poly(vinyl alcohol), whose pyrolysis carbon possesses high conductivity of 8.88 × 10−1 S/cm, was used to synthesize xLiFePO4/C·(1 − x)Li3V2(PO4)3/C cathode. It was characterized by X-ray diffraction, scanning electron microscopy, conductivity, cyclic voltammetry, and galvanostatic charge and discharge experiments. Results show that LiFePO4/C and Li3V2(PO4)3/C coexists in the cathode. The particles sizes of 0.75LiFePO4/C·0.25Li3V2(PO4)3/C (x = 0.75) are much smaller than 100 nm due to the role of poly(vinyl alcohol). Its conductivity is 8.79 × 10−2 S/cm. The oxidative and reductive peaks in cyclic voltammetry are sharp and symmetrical. Their low potential gaps indicate that the extractions and insertions of lithium ion possess excellent reversibility. Its discharge capacities at 1 and 5 C are 141.1 and 100.1 mAh/g. The more Li3V2(PO4)3/C in cathode results in the deterioration of electrochemical performances due to its low theoretical capacity. It is concluded that poly(vinyl alcohol) is an effective carbon source in the preparation of xLiFePO4/C·(1 − x)Li3V2(PO4)3/C composite cathode with excellent performances.

Investigation of the Phenomenon of Propagated Sensation along the Channels in the Upper Limb Following Administration of Acupuncture and Mock Laser

Shohreh Razavy,Marcus Gadau,Shi Ping Zhang,Fu Chun Wang,Sergio Bangrazi,Christine Berle,Mahrita Harahap,Tie Li,Wei Hong Li,Christopher Zaslawski 사단법인약침학회 2017 Journal of Acupuncture & Meridian Studies Vol.10 No.5

Background: Similar to De Qi psychophysical responses, propagated sensation along the channels (PSC) is considered an important phenomenon in traditional Chinese acupuncture. In acupuncture clinical trials, different acupuncture manipulation techniques are used to enhance the propagation of sensation along the channels to facilitate an optimum therapeutic result. Aim: To examine and compare the PSC reported by participants in a clinical trial following the administration of acupuncture and inactive mock laser. Methods: The study was embedded in a two-arm parallel design multicenter, randomized clinical trial, the Tennis Elbow AcupuncturedInternational StudydChina, Hong Kong, Australia, Italy (TEA IS CHAI). Needle sensations were measured using a validated instrument, the Massachusetts General Hospital Acupuncture Sensation Spreading Scale. Ninety-six participants with lateral elbow pain were randomly allocated into two groups in a 1:1 ratio; the acupuncture treatment group (n Z 47) and the mock laser control group (n Z 49). Participants in both groups received the intervention at two acupoints, LI10 and LI11, consisting of 2 minutes of either standardized needle manipulation or mock laser at each acupoint with a rest period between each intervention period. Data were collected immediately following the interventions at the first and the ninth session within the clinical trial. Results: Although participants in both groups perceived PSC radiating to similar sites along the upper limb, the frequency of the reported radiation sites among the two intervention groups for both radiation up the limb (p < 0.05) and radiation down the limb (p < 0.001) were statistically significantly different. Among the radiating sensation sites recorded within the two study groups, the sensations were reported as radiating a greater distance down the forearm to the wrist compared to up the arm. Evaluation of PSC across the four study sites revealed a statistically significant difference in frequency of the reported radiation down the limb sites in each study group and radiation up the limb sites only in control group only (p < 0.001). Conclusion: The findings of the study demonstrated that the PSC phenomenon is not just associated with needling but can be perceived when using a mock laser. Trial registration: Australian and New Zealand Clinical Trial Registry reference: ACTRN12613001138774 on 11th of October 2013.

Current state of research about acupuncture for the treatment of COVID-19: A scoping review

Chen Chen,Jie Zhan,Hao Wen,Xiaojing Wei,Lu Ding,Chenyang Tao,Cui Li,Peiming Zhang,Yuyuan Tang,Jing-chun Zeng,Li-ming Lu 한국한의학연구원 2021 Integrative Medicine Research Vol.10 No.-

Background Since the outbreak of coronavirus disease (COVID-19), acupuncture has been widely used in the treatment of COVID-19. The research community has responded rapidly and has already published many research articles about this topic. Methods We searched PubMed, Embase, Cochrane Library as well as CNKI, Wanfang and VIP from January 1, 2020 to July 31, 2021. The dates of publication, language of publication, methodological characteristics and the key findings were analyzed separately. The data are presented as bar graphs, structured tables and figures. Results In this scoping review, 16 research articles were included: 7 case reports, 6 observational studies, 1 review, 1 RCT and 1 nonrandomized clinical trial. The majority of the articles (81.3%) were published by Chinese scholars, 12.5% articles were by scholars in the United States, and 6.3% articles were by scholars in Iran. The included studies reported that acupuncture could alleviate the symptoms of COVID-19 patients, shorten their hospitalization days, and is effective for the elderly. There were no side effects reported. The most frequent acupoints used were LI4, PC6, ST36 and KI3. They reported many obstacles in implementing acupuncture therapy for treating COVID-19 patients. Conclusion Acupuncture has a good effect for the treatment of COVID-19, but high-quality evidence support is still lacking. Coupled with the difficulties that acupuncturists experienced during the process of treatment, the promotion of acupuncture treatment for COVID-19 faces many obstacles. Background Since the outbreak of coronavirus disease (COVID-19), acupuncture has been widely used in the treatment of COVID-19. The research community has responded rapidly and has already published many research articles about this topic. Methods We searched PubMed, Embase, Cochrane Library as well as CNKI, Wanfang and VIP from January 1, 2020 to July 31, 2021. The dates of publication, language of publication, methodological characteristics and the key findings were analyzed separately. The data are presented as bar graphs, structured tables and figures. Results In this scoping review, 16 research articles were included: 7 case reports, 6 observational studies, 1 review, 1 RCT and 1 nonrandomized clinical trial. The majority of the articles (81.3%) were published by Chinese scholars, 12.5% articles were by scholars in the United States, and 6.3% articles were by scholars in Iran. The included studies reported that acupuncture could alleviate the symptoms of COVID-19 patients, shorten their hospitalization days, and is effective for the elderly. There were no side effects reported. The most frequent acupoints used were LI4, PC6, ST36 and KI3. They reported many obstacles in implementing acupuncture therapy for treating COVID-19 patients. Conclusion Acupuncture has a good effect for the treatment of COVID-19, but high-quality evidence support is still lacking. Coupled with the difficulties that acupuncturists experienced during the process of treatment, the promotion of acupuncture treatment for COVID-19 faces many obstacles.

Catalytic synthesis and enhanced Curie temperature of ε-Fe₃N@C nanostructure synthesized in a tetraethylenepentamine solution

Li, Yong,Pan, Desheng,Li, Da,Feng, Yang,Choi, C.J.,Liu, Wei,Zhang, Zhidong Elsevier 2018 Journal of magnetism and magnetic materials Vol.465 No.-

<P><B>Abstract</B></P> <P>ε-Fe<SUB>3</SUB>N@C nanocrystals without oxidation are one-pot synthesized by using the iron(II) acetylacetonate and tetraethylenepentamine (TEPA) as Fe and N precursors under a low temperature (533 K) in the presence of a small quantity of Pt atoms as the co-catalyst. The ε-Fe<SUB>3</SUB>N@C nanoparticles with a core-shell structure are nearly spherical and have a wide particle size distribution of 100–500 nm in diameter. Fe nanoparticles obtained by reduction of Fe<SUP>2+</SUP> with TEPA are an effective catalyzer for decomposing TEPA to produce N and C atoms at a temperature much lower than the boiling point of TEPA. The diffusion of N atoms into Fe nanoparticles for the formation of ε-Fe<SUB>3</SUB>N@C is proposed, based on the results obtained by kinetically controlling the synthetic temperature and surfactants. The ε-Fe<SUB>3</SUB>N@C nanoparticles have an excellent saturation magnetization of 135.5 emu/g at room temperature. A significantly enhanced Curie temperature (T<SUB>C</SUB>) of 614 K is reached in the present ε-Fe<SUB>3</SUB>N@C nanoparticles, which is much higher than the T<SUB>C</SUB> values in the previously reported ε-Fe<SUB>3</SUB>N<SUB>x</SUB>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Tetraethylenepentamine is proposed as a new N source to synthesize Fe nitride. </LI> <LI> Core-shelled ε-Fe<SUB>3</SUB>N@C nanoparticles are one-pot synthesized at 260 °C. </LI> <LI> Curie temperature of ε-Fe<SUB>3</SUB>N is significantly enhanced to 614 K. </LI> <LI> ε-Fe<SUB>3</SUB>N@C shows a high saturation magnetization of 135.5 emu/g at 300 K. </LI> </UL> </P>