Synthesis of full concentration gradient cathode studied by high energy X-ray diffraction

Li, Yan,Xu, Rui,Ren, Yang,Lu, Jun,Wu, Huiming,Wang, Lifen,Miller, Dean J.,Sun, Yang-Kook,Amine, Khalil,Chen, Zonghai Elsevier 2016 Nano energy Vol.19 No.-

<P><B>Abstract</B></P> <P>Nickel-rich metal oxides have been widely pursued as promising cathode materials for high energy-density lithium-ion batteries. Nickel-rich lithium transition metal oxides can deliver a high specific capacity during cycling, but can react with non-aqueous electrolytes. In this work, we have employed a full concentration gradient (FCG) design to provide a nickel-rich core to deliver high capacity and a manganese-rich outer layer to provide enhanced stability and cycle life. <I>In situ</I> high-energy X-ray diffraction was utilized to study the structural evolution of oxides during the solid-state synthesis of FCG lithium transition metal oxide with a nominal composition of LiNi<SUB>0.6</SUB>Mn<SUB>0.2</SUB>Co<SUB>0.2</SUB>O<SUB>2</SUB>. We found that both the pre-heating step and the sintering temperature were critical in controlling phase separation of the transition metal oxides and minimizing the content of Li<SUB>2</SUB>CO<SUB>3</SUB> and NiO, both of which deteriorate the electrochemical performance of the final material. The insights revealed in this work can also be utilized for the design of other nickel-rich high energy-density cathode materials.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Solid-state synthesis of FCG cathode is investigated by <I>in situ</I> XRD. </LI> <LI> Covariance analysis and Rietveld refinement are used to analyze the HEXRD data. </LI> <LI> Synthetic optimization of FCG cathode with excellent electrochemical performance. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Benefit from the covariance analysis and Rietveld refinement of <I>in situ</I> HEXRD data during the solid state synthesis, we can optimized the solid state synthesis conditions in a short time. And the full concentration gradient cathode composites (nickel-rich core and manganese-rich outer layer) with excellent electrochemical performance are obtained.</P> <P>[DISPLAY OMISSION]</P>

A Novel Molecular Grading Model: Combination of Ki67 and VEGF in Predicting Tumor Recurrence and Progression in Non-invasive Urothelial Bladder Cancer

Chen, Jun-Xing,Deng, Nan,Chen, Xu,Chen, Ling-Wu,Qiu, Shao-Peng,Li, Xiao-Fei,Li, Jia-Ping Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.5

Purpose: To assess efficacy of Ki67 combined with VEGF as a molecular grading model to predict outcomes with non-muscle invasive bladder cancer (NMIBC). Materials: 72 NMIBC patients who underwent transurethral resection (TUR) followed by routine intravesical instillations were retrospectively analyzed in this study. Univariate and multivariate analyses were performed to confirm the prognostic values of the Ki67 labeling index (LI) and VEGF scoring for tumor recurrence and progression. Results: The novel molecular grading model for NMIBC contained three molecular grades including mG1 (Ki67 $LI{\leq}25%$, VEGF $scoring{\leq}8$), mG2 (Ki67 LI>25%, VEGF $scoring{\leq}8$; or Ki67 $LI{\leq}25%$, VEGF scoring > 8), and mG3 (Ki67 LI > 25%, VEGF scoring > 8), which can indicate favorable, intermediate and poor prognosis, respectively. Conclusions: The described novel molecular grading model utilizing Ki67 LI and VEGF scoring is helpful to effectively and accurately predict outcomes and optimize personal therapy.

Mechanism and process for the extraction of lithium from the high magnesium brine with N,N-bis(2-ethylhexyl)-2-methoxyacetamide in kerosene and FeCl3

Lianmin Ji,Licheng Zhang,Dong Shi,Xiaowu Peng,Jinfeng Li,Yuze zhang,Taoshan Xu,Lijuan Liao 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.113 No.-

The degradation of TBP has become a stumbling block to the industrial continuous production of lithiumchloride extraction from brines with high Mg/Li ratio by solvent extraction. To develop a more stable andmore efficient extraction system, a novel amide system, containing newly synthesized extractant N,N-bis(2-ethylhexyl)-2-methoxyacetamide (NBEHMOA), FeCl3 6H2O and sulfonated kerosene, was proposed inthis work. Compared with TBP and N523, NBEHMOA extracted Li+ and H+ in the sequence of TBP ˃NBEHMOA ˃ N523 and N523 ˃ TBP ˃ NBEHMOA respectively. The solution containing 5.5 mol/L LiCland 0.5 mol/L HCl was used as the eluent in the scrubbing process. A Li+ extraction efficiency of 96.7%and 22.31 g/L Li+ in the stripping solution were achieved by the whole process with counter-currenttwelve stages. The extraction mechanism investigated via FT-IR spectroscopy illustrated that the metalions Fe3+ and Li+ were mainly coordinated by the carbonyl C = O in NBEHMOA. This novel amide systemcan successfully achieve the cascade extraction effect for lithium, Li/Mg separation and avoid the generationof phase interface objects through counter-current extraction of lithium from brine at a lower acidity. This work provided a novel extraction system to recover lithium from the higher magnesium/lithiumratio brines.

Preparation of lithium-doped NaV6O15 thin film cathodes with high cycling performance in SIBs

Xu Hai-Yan,Ruan Jun Hai,Liu Fang Lin,Li Dong-Cai,Zhang Feng-Jun,Wang Ai-Guo,Sun Dao-Sheng,오원춘 한국세라믹학회 2022 한국세라믹학회지 Vol.59 No.3

Lithium ions-doped NaV6O15 thin films have been prepared using a simple low temperature liquid phase deposition method and subsequent annealing process. X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), scanning elec- tron microscopy (SEM), and photoelectron spectroscopy (XPS) have been used to study the structural and physicochemical characteristics of the NaV6O15 film. The films were grown on the FTO conductive glass and used directly as an electrode of sodium ion batteries. The prepared lithium ions-doped NaV6O15 thin film electrodes showed an excellent cycling stability and discharge capacity, which may be attributed to the stability of the Li+ embedded into the gap between the V–O layers to maintain the structure and its stable β-phase structure transformed after the first cycle. The cycling stability greatly improved with increasing annealing temperature, while the discharge capacity decreased. The capacities of the film electrodes annealed at 400 °C and 450 °C maintained above 97% after 100 cycles. The lithium-doped NaV6O15 underwent a phase transition dur- ing the first charge/discharge cycle. The new transformed phase has perfect crystal structure stability undergoing insertion and deinsertion of Na+. Therefore, the lithium-doped NaV6O15 thin film possesses good cycling stability and is expected to be a promising thin film cathode for sodium-ion batteries.

Optimized Assembly of Micro-/Meso-/Macroporous Carbon for Li–S Batteries

Qiong Tang,Heqin Li,Min Zuo,Jing Zhang,Yiqin Huang,Peiwen Bai,Jiaqi Xu,Kuan Zhou 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.2

In order to explore the effect of hierarchical porous carbon on the performances of Li–S batteries, we synthesized three kinds of micro-/meso-/macroporous carbon materials with different pore properties by facile hard-template method. Different from the majority of reports on porous carbon ensuing large specific surface area (SSA) and total pore volume, it was found that in the case of identically high sulfur content, the pore size distribution substantially influences the performances of Li–S batteries rather than the SSA and total pore volume. Furthermore, in the assembly of micro-/meso-/macropores, the micropore volume ratio to the total pore volume is dominant to the capabilities of batteries. Among the samples, the porous carbon carbonized with the precursor of sucrose at 950℃ presents the highest initial discharge specific capacity of 1327 mAh/g and retention of 630 mAh/g over 100 cycles at 0.2C rate along with the best rate capability. This sample possesses the largest micropore volume ratio of 47.54% but a medium SSA of 1217 m2 /g and inferior total pore volume of 0.54 cm3 /g. The abundant micropores effectively improve the conductivity of dispersed sulfur particles, inhibit the loss of sulfur series and enable the cathode to exhibit superior electrochemical performances.

A Mild Strategy to Strengthen Three Dimensional Graphene Aerogel for Supporting Sulfur as a Free‐standing Cathode in Lithium–Sulfur Batteries

Yinglin Yan,Haichao Qin,Yiqi Wei,Rong Yang,Yunhua Xu,Liping Chen,Qiaole Li,Mangmang Shi 대한화학회 2018 Bulletin of the Korean Chemical Society Vol.39 No.5

Recently, three dimensional graphene aerogel (3DGA) supported sulfur microparticles was used as a cathode material for lithium?sulfur batteries, which was considered as one of the most promising next generation rechargeable batteries due to its ultra?high theoretical specific capacity (1675 mAh/g). However, the mechanical strength of 3DGA remains an issue for further application. Herein, a strengthened 3DGA (S3DGA) was achieved by soaking in a low concentration ammonia solution at a relative low temperature. Then the S3DGA loaded sulfur (S3DGA?S) was cut into a round piece and directly used as a cathode without additional binders or conductive additives in Li?S batteries. The mechanical strength, microstructure, and electrochemical properties were investigated by compare with a 3DGA prepared without strengthen. The S3DGA?S presented good mechanical strength, excellent capacity retention, and lower electrochemical impedance.

A Spectroscopic Study on Singlet Oxygen Production from Different Reaction Paths Using Solid Inorganic Peroxides as Starting Materials

Li, Qingwei,Chen, Fang,Zhao, Weili,Xu, Mingxiu,Fang, Benjie,Zhang, Yuelong,Duo, Liping,Jin, Yuqi,Sang, Fengting Korean Chemical Society 2007 Bulletin of the Korean Chemical Society Vol.28 No.10

Using solid inorganic peroxides (including Li2O2, Na2O2, SrO2 and BaO2) as starting materials, three reaction paths for singlet oxygen (1O2) production were developed and studied. Their 1O2 emission spectra in the near- IR region and visible region from these reaction paths were simultaneously recorded by a near-IR sensitive Optical Multichannel Analyzer and a visible sensitive Optical Spectrum Analyzer, respectively. The comparison of their 1O2 emission spectra indicated that: (1) in term of the efficiency for 1O2 production, the gasliquid- solid reaction path (in which Cl2 or HCl and H2O reacted with the solid inorganic peroxides suspension in CCl4) was prior to the gas-solid reaction path (in which Cl2 or HCl reacted with the solid inorganic peroxides suspension in CCl4), but was inferior to the gas-liquid reaction path (in which Cl2 or HCl reacted with the solid inorganic peroxides solution in H2O or D2O); (2) the alkali metal peroxides (such as Li2O2 and Na2O2) was prior to the alkaline earth metal peroxides (such as SrO2 and BaO2) as the solid reactants, and Cl2 was favorable than HCl as the gas reactant in efficiency for 1O2 production in these reaction paths.

Modeling, Preparation, and Elemental Doping of Li₇La₃Zr₂O₁₂ Garnet-Type Solid Electrolytes: A Review

Cao, Shiyu,Song, Shangbin,Xiang, Xing,Hu, Qing,Zhang, Chi,Xia, Ziwen,Xu, Yinghui,Zha, Wenping,Li, Junyang,Gonzale, Paulina Mercedes,Han, Young-Hwan,Chen, Fei The Korean Ceramic Society 2019 한국세라믹학회지 Vol.56 No.2

Recently, all-solid-state batteries (ASSBs) have attracted increasing interest owing to their higher energy density and safety. As the core material of ASSBs, the characteristics of the solid electrolyte largely determine the performance of the battery. Thus far, a variety of inorganic solid electrolytes have been studied, including the NASICON-type, LISICON-type, perovskite-type, garnet-type, glassy solid electrolyte, and so on. The garnet Li₇La₃Zr₂O₁₂ (LLZO) solid electrolyte is one of the most promising candidates because of its excellent comprehensively electrochemical performance. Both, experiments and theoretical calculations, show that cubic LLZO has high room-temperature ionic conductivity and good chemical stability while contacting with the lithium anode and most of the cathode materials. In this paper, the crystal structure, Li-ion transport mechanism, preparation method, and element doping of LLZO are introduced in detail based on the research progress in recent years. Then, the development prospects and challenges of LLZO as applied to ASSBs are discussed.

A Spectroscopic Study on Singlet Oxygen Production from Different Reaction Paths Using Solid Inorganic Peroxides as Starting Materials

Qingwei Li*,Fang Chen,Weili Zhao,Mingxiu Xu,Benjie Fang,Yuelong Zhang,Liping Duo,Yuqi Jin,Fengting Sang 대한화학회 2007 Bulletin of the Korean Chemical Society Vol.28 No.10

Using solid inorganic peroxides (including Li2O2, Na2O2, SrO2 and BaO2) as starting materials, three reaction paths for singlet oxygen (1O2) production were developed and studied. Their 1O2 emission spectra in the near-IR region and visible region from these reaction paths were simultaneously recorded by a near-IR sensitive Optical Multichannel Analyzer and a visible sensitive Optical Spectrum Analyzer, respectively. The comparison of their 1O2 emission spectra indicated that: (1) in term of the efficiency for 1O2 production, the gas-liquid-solid reaction path (in which Cl2 or HCl and H2O reacted with the solid inorganic peroxides suspension in CCl4) was prior to the gas-solid reaction path (in which Cl2 or HCl reacted with the solid inorganic peroxides suspension in CCl4), but was inferior to the gas-liquid reaction path (in which Cl2 or HCl reacted with the solid inorganic peroxides solution in H2O or D2O); (2) the alkali metal peroxides (such as Li2O2 and Na2O2) was prior to the alkaline earth metal peroxides (such as SrO2 and BaO2) as the solid reactants, and Cl2 was favorable than HCl as the gas reactant in efficiency for 1O2 production in these reaction paths.

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.