改善益生菌粉剂质量的辅料组合物

市售益生菌粉剂产品由于生产条件的限制,产品水分活度偏高会导致产品货架期乳酸菌稳定性差,存活率低。另外,辅料搭配不合理会导致成品的服用体验不好,工艺顺应性不良。因此为确定一种改善益生菌粉剂质量的辅料组合物,对糖醇类矫味剂和糊精类分散剂进行系统分析,从感官验证、水分活度、乳酸菌稳定性和工艺顺应性四个维度进行试验验证,结果显示赤藓糖醇、麦芽糖醇和抗性糊精在特定比例组合下具有良好的粉剂袋包工艺顺应性,并能有效地保证水分活度,同时还能显著提高粉剂在口腔溶解速度,降低粉末口腔结团和粘牙感,从而极大地改善口感。将研究发现的辅料组合物应用到益生菌粉剂,能有效改善益生菌粉剂产品质量,充分保障产品货架期稳定性和消费者口感需求。

An electrochemical impedance spectroscopic study of the electronic and ionic transport properties of LiCoO_2 cathode

The storage behavior and process of the first delithiation-lithiation of LiCoO2 cathode were investigated by electrochemical impedance spectroscopy(EIS). The electronic and ionic transport properties of LiCoO2 cathode along with variation of electrode potential were obtained in 1 mol·L?1 LiPF6-EC:DMC:DEC electrolyte solution. It was found that after 9 h storage of the LiCoO2 cathode in electrolyte solu-tions,a new arc appears in the medium frequency range in Nyquist plots of EIS,which increases with increasing the storage time. In the charge/discharge processes,the diameter of the new arc is reversi-bly changed with electrode potential. Such variation coincides well with the electrode potential de-pendence of electronic conductivity of the LiCoO2. Thus this new EIS feature is attributed to the change of electronic conductivity of LixCoO2 during storage of the LiCoO2 cathode in electrolyte solutions,as well as in processes of intercalation-deintercalationtion of lithium ions. It has been revealed that the reversible increase and decrease of the resistance of SEI film in charge-discharge processes can be also ascribed to the variation of electronic conductance of active materials of the LiCoO2 cathode.

Two-and three-electrode impedance spectroscopic studies of graphite electrode in the first lithiation

The first lithiation of graphite electrode was investigated by electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM) in a two-electrode button cell and a three-electrode glass cell. The results demonstrate that the study of the variation of EIS feature of the graphite electrode in the two-electrode button cell with electrode polarization potential decreasing in the first lithiation cannot be used to investigate the formation mechanism of the solid electrolyte interphase (SEI) film. However, the formation and growth process of the SEI film can be acquired by investigating the variation of EIS features of the graphite electrode in the three-electrode glass cell with the decrease of electrode po-larization potential in the first lithiation. Moreover, the results also point out that the SEI film on graph-ite electrode is mainly formed between 1.0 and 0.6 V in the first lithiation.

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 investi- gated by electrochemical impedance spectroscopy (EIS). The results illustrated that the first arc in the high-frequency range observed in the Nyquist dia- gram 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 pro- posed 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 capaci- tance of double layer along with the increase of po- larization potentials.

Preparation and characteriza-tion of a novel composite mi-croporous polymer electrolyte for Li-ion batteries

A novel composite microporous polymer elec- trolyte composed of poly(vinylidene fluoride-co-hexafluorop- ropylene) (PVdF-HFP) and mesoporous SBA-15 was pre- pared. The composite solid polymer electrolyte (CSPE) ex- hibits ionic conductivity as high as 0.30 mS·cm?1 with a composition of SBA-15︰PVdF-HFP=3︰8 at room tem- perature. Infrared transmission spectroscopic results sug- gested that the mechanism of micropore formation is similar to that of the phase inversion. X-ray diffraction (XRD) results demonstrated that the addition of SBA-15 inhibits the crys- tallization of PVdF-HFP, while the SBA-15 preserves well its ordered mesoporous structure during the course of prepara- tion. The Li/CSPE/MCF of half-cell was assembled, and it showed a good electrochemical and cyclability performance during charge-discharge cycles.