Application of IR spectroscopy in Li-ion batteries studies

综述了傅立叶变换红外光谱在锂离子电池基础研究中应用的进展,主要包括负极表面SEI膜的组成和结构、电解液稳定性、电极材料的结构表征以及聚合物电解质的表征等。Progress in applications of FTIRS in studies of Li-ion batteries was reviewed. It included composition and structure of SEI film on anode, stability of electrolyte, structure characterization of electrode materials and characterization of polymer electrolyte.国家"973"项目(2002CB211804);; 国家自然科学基金项目(20173045

一种新型微孔聚合物电解质的制备与表征

以介孔分子筛SBA-15为填料,探索出一种无需使用增塑剂制备微孔型聚合物电解质的新方法.当SBA-15︰PVdF-HFP(偏氟乙烯-六氟丙烯共聚物)=3︰8时,所制备的复合固体聚合物电解质(CSPE)室温电导率达0.30mS·cm~(-1).红外透射光谱显示,成膜液中溶剂分子和SBA-15分子筛之间的相互作用所引发的相分离导致微孔的形成.X射线衍射(XRD)结果表明,SBA-15分子筛的加入,降低了聚合物电解质的结晶度,而SBA-15分子筛仍保持原有的骨架结构.所组装的Li/CSPE/MCF电池具有较为平稳的充放电平台,首次循环的库仑效率约为85.0%,经过20次循环后,容量保持率为94.0%

石墨负极首次阴极极化过程的电化学阻抗谱研究

运用电化学阻抗谱(EIS)研究了石墨负极在1mol/LLiPF6-EC:DEC:DMC电解液中的首次阴极极化过程.在1.0V以下,观察到EIS高频区域出现半圆及其随极化电位降低而不断增长的过程,发现该EIS特征与固体电解质相界面膜(SEI膜)有关.选取适当的等效电路拟合了不同电位下的EIS实验数据,深入分析了SEI膜的成膜过程及其对SEI膜阻抗、电荷传递电阻和双电层电容的影响

The Communities of Ammonia-oxidizing Organisms in Pearl River Estuary Sediments

[目的]对珠江口海岸带沉积物中的氨氧化细菌和古菌的组成进行分析,并进行定量研究。[方法]用构建克隆文库和Q-PCr定量的方法对珠江口沉积物中氨氧化细菌和古菌AMOA基因的含量和多样性特征进行研究。[结果]在2个沉积物表层,氨氧化古菌的含量是细菌的9和22倍,揭示氨氧化古菌在珠江口的氨氧化过程中起主导作用;系统发育分析表明大多数古菌和细菌的AMOA基因序列与不可培养的源于河口区和污染区域的环境克隆子序列有较高的同源性;细菌AMOA序列可分成5个类群(CluSTEr A、b、C、d和E),均属于nITrOSOMOnAS类群,其中CluSTEr A是主要类群(72.1%);古菌AMOA序列分析表明来自于表层的序列有52.2%属于“水/沉积物“簇,47.8%属于“土壤/沉积物“簇,而沉积物底层厌氧区,检测到的古菌AMOA基因93.3%属于“土壤/沉积物“簇,6.7%属于“水/沉积物“簇,且AMOA基因数量略高于表层。[结论]该研究有助于了解珠江口区域氮的循环过程,为氮的富营养化处理提供重要的理论依据。[Objective] This study aimed to investigate the abundance and composition of ammonia-oxidizing organism in Pearl River Estuary sediment.[Method] Based on amoA genes,we detected the abundance and composition of ammonia-oxidizing organism in Pearl River Estuary sediment by using quantitative real-time polymerase chain reaction(Q-PCR),cloning and sequencing approaches.[Result] The results of Q-PCR presented that ammonia-oxidizing archaea were more abundant than ammonia-oxidizing bacteria in the top of sediment cores,with AOA to AOB ratios 8.96(site Q5) and 3.69(site Q7).It suggested that ammonia-oxidizing archaea maybe play more important roles than ammonia-oxidizing bacteria in the process of ammonia oxidation in the Pearl River Estuary sediment.In the top sediment layer of Q7,bacterial amoA-like gene sequences were dominated by Nitrosomonas-like sequence types,which could be classified into five groups(clusters A,B,C,D,and E).Interestingly,archeal amoA-like gene was successfully amplified while bacterial amoA-like gene failed to be detected.These archeal amoA-like genes fell into two groups "water column/sediment" cluster and "soil/sediment" cluster.Most of the sequences(93.3%) in the bottom sediment layer of Q7 fell into "soil/sediment" cluster.[Conclusion] This study helps to realize the cycle of nitrogen in Pearl River Estuary region,and thus to provide theoretical support for the treatment of nitrogen eutrophication.国家973前期项目(2006CB708200);国家自然科学重点基金项目(40532011

Progresses on the research of the interfacial compatibility between lithium electrode and polymer electrolyte

对聚合物电解质(PE)的研究主要包括两个方面:第一,在保持聚合物电解质机械强度的前提下提高其室温离子迁移性(包括离子电导率和锂离子迁移数);第二,改善聚合物电解质与电极,特别是与锂电极的界面相容性,即在降低锂电极/聚合物电解质(Li/PE)初始界面阻抗的同时增强其界面稳定性。改善Li/PE界面相容性对于锂聚合物蓄电池的商业化具有重要意义。综述了Li/PE界面研究特点及Li/PE界面研究的最新进展。It mainly includes two aspects for the research of polymer electrolyte (PE): First is the enhancement of self-performance, i.e., improving the ability of ion transfer (including ionic conductivity and Li+ transference number) at room temperature in the case of good mechanical strength; Second is the improvement of the interfacial compatibility with electrodes, especially with lithium electrode, i.e., enhancing the interfacial stability between lithium electrode and polymer electrolyte (Li / PE) on the condition of reducing initial interfacial resistance. It is of significance for the commercialization of lithium polymer secondary batteries to improve the interfacial compatibility between Li / PE. In this paper, the general features on the research of Li / PE interface were introduced, and the progresses on the research of the interfacial compatibility between Li/PE were reviewed.国家“973”项目(2002CB211804);; 国家自然科学基金(90206039)资

LiCoO_2正极材料电子和离子传输特性的电化学阻抗谱研究

运用电化学阻抗谱(EIS)研究了LiCoO2正极的电子和离子传输特性,及其在电解液中贮存和充放电过程中的变化规律.发现当LiCoO2正极在电解液中贮存达到9h时,在EIS的中频区域出现一个新的半圆,随着贮存时间进一步延长,该半圆不断增大.在充放电过程中,这一中频区域半圆随电极电位的变化发生可逆的增大和减小,其变化规律与LixCoO2电子电导率随电极电位的变化规律相一致.因此,这一新的EIS特征应归属于LiCoO2正极在贮存或锂离子嵌脱过程中LixCoO2电子电导率的变化.研究结果还发现,LiCoO2正极表面SEI膜阻抗在充放电过程中可逆地增大和减小,也可归因于充放电过程中LiCoO2正极活性材料电子电导率的变化.国家重点基础研究发展计划(批准号:2002CB211804)资助项

Electrochemical Impedance Spectroscopic Study of the First Delithiation of Spinel Lithium Manganese Oxide

研究了尖晶石锂锰氧化物电极首次脱锂过程中的电化学阻抗特征.通过选取适当的等效电路拟合实验所得的电化学阻抗谱数据,获得了首次脱锂过程中固体电解质相界面膜(SEI膜)的电阻、电容以及电荷传递电阻、双电层电容等随电极极化电位的变化规律.The first delithiation of the spinel LiMn2O4 electrode was studied using electrochemical impedance spectroscopy (EIS). Appropriate equivalent circuits were proposed to fit the experimental EIS data. Based on the fitting results, the variation of the capacitance and the resistance of SEI(solid electrolyte interphase) film, the resistance of charge transfer, and the capacitance of double layer along with the increase of polarization potential were quantitatively analyzed. The results demonstrated that the resistance and the thickness of the SEI film formed on the spinel LiMn2O4 electrode were both increased with the increase of polarization potential in the first delithiation of the spinel LiMn2O4 electrode; The charge transfer resistance decreases below 4.15 V and increases above 4.15 V, corresponding to the two-step reversible (de)intercalation of lithium between LiMn2O4 and λ-MnO2; The double layer capacitance was influenced by both the state of the spinel LiMn2O4 electrode(different polarization potential) and the two-step reversible (de)intercalation of lithium.国家重点基础研究发展规划项目(2002CB211804)资

Scanning of c-kit mutations in acute myeloid leukemia using probe melting curve method

目的用改良的杂交探针结合溶解曲线新方法检测急性髓性白血病C-kIT基因17号外显子上基因突变。方法利用PrIMEr PrEMIErV5.00、TM uTIlITyV1.3等软件设计引物探针,两个阶段探针分别针对d816、n820和n822等突变热点。取患者dnA样品5μl进行PCr扩增及熔解曲线分析,PCr扩增产物进行测序分析并与熔解曲线分析方法进行比较。结果阳性质粒灵敏度试验的结果显示,n820g的灵敏度为10%,其余突变灵敏度均能达到5%。12例Cbf-AMl标本中,5例检测为阳性,突变率为41.7%,测序结果与测序检测结果相符。结论新方法具有方便快速、灵敏度高、特异性好等特点,可用于Cbf-AMl患者的个体化诊断和治疗。Objective To detect c-kit gene mutations of acute myeloid leukemia in the hotspot exon 17 of the c-kit gene using a modified hybridization probe combining with melting curve.Methods Primer Premier v5.00 and Tm Utility v1.3 software were used to design the primers and probe,the probe contained two parts,the first segment of the probe could detect mutations around D816 and the second segment could detect mutations at N820 and N822.5 μl DNA samples from patients were used for PCR amplification and melting curve analysis.PCR products were sent to be sequenced,these results were compared with those of the mutation-positive plasmids.Results The detection sensitivity on positive control plasmids was 10% for N820G and 5% for the other mutations.c-kit mutations were identified in 5 of 12 patients with CBF-AML(41.7%),the result was confirmed by sequencing analysis.Conclusion The new method is simple,rapid,and specific with high sensitivity and could be used in individual diagnosis and treatment of CBF-AML patients

Studies of the first lithiation of graphite materials by electrochemical impedance spectroscopy

First lithiation of graphite electrode in 1 mol/L LiPF6-EC:DEC:DMC electrolyte was investigated by electrochemical impedance spectroscopy (EIS). The results illustrated that the first arc in the high-frequency range observed in the Nyquist diagram appears near 0.9 V in the initial lithiation of graphite electrode, and its diameter increases with the decrease of polarization potential. These EIS features were attributed to the formation and growth of SEI film. Appropriate equivalent circuit was proposed to fit the experimental EIS data. The fitting results revealed the process of the formation and growth of SEI film, and evaluated quantitatively the resistance of charge transfer, as well as the capacitance of double layer along with the increase of polarization potentials

LiCoO_2电极/电解液界面特性的电化学阻抗谱研究

运用电化学阻抗谱研究了LiCoO2电极在电解液中的贮存和首次脱锂过程.发现LiCoO2电极在电解液中,随浸泡时间延长其表面SEI膜不断增厚,归结为LiCoO2电极与电解液之间的自发反应导致生成一些高介电常数的有机碳酸锂化合物.研究结果指出LiCoO2电极首次脱锂过程中,SEI膜在3.8~3.95V电位区间发生可逆坍塌,对应其可逆溶解;由于过充反应,当电位大于4.2VSEI膜迅速增厚.研究结果同时表明,Li/LiCoO2电池体系的感抗来源于充放电过程中LiCoO2电极中存在LiCoO2/Li1?xCoO2局域浓差电池.发现锂离子在LiCoO2电极中的嵌脱过程可较好地用Langmuir嵌入等温式和Frumkin嵌入等温式描述,测得LiCoO2电极中锂离子嵌脱过程中电荷传递反应的对称因子α=0.5.国家重点基础研究发展计划资助项目(批准号:2002CB211804