Polyporus umbellatus is one of the most valuable medicinal fungi, and its sclerotium has been used as a diuretic agent and an antidote in traditional Chinese medicine. In nature, Polyporus umbellatus has almost been depleted because of over-exploitation and lack of natural habitats. Thus, artificial sclerotia production has increased. This study aimed at finding an effective method to induce sclerotia, and selected the split-plate culture method. One side contained fructose agar medium (FAM), while the other side contained nutrient-limited medium. It was observed that sclerotia were only formed on the nutrient-limited medium side but scarcely emerged on the FAM side, even when the fructose concentration on both sides were the same. The sclerotial differentiation rate was 100% and the sclerotial yield was 106% higher than in the conventional way. In conclusion, the split-plate culture method is an effective way to induce P. umbellatus sclerotia in the laboratory.

LiCoO2 was coated with ZrO2 by using an impregnation method followed by a calcination process at 550°C for 8h. X-ray absorption near-edge spectrum (XANES) and X-ray diffraction (XRD) investigations showed that the structure of LiCoO2 did not alter by ZrO2 coating. Cyclic voltammogram indicated that the coating film ZrO2 exerted influences on transporting of Li+ ions. From electrochemical tests, in the voltage range of 3.00–4.25V, the coated LiCoO2 shows enhanced electrochemical properties over bare LiCoO2 at both elevated temperature and room temperature.

LiFePO4/C composites were synthesized by a solid state reaction method utilizing two-component mixture of FeC2O4·2H2O and LiH2PO4. Sintering the reactants with C12H22O11 at different temperatures above 650°C yields a product containing Fe2P as a secondary phase to olivine LiFePO4. The LiFePO4/Fe2P/C composite synthesized at 750°C exhibits an excellent electrochemical performance, i.e. a discharge capacity of 152mAh/g with a smooth plateau of 3.37V and a good cycle performance at 0.2C charge/discharge current rate. Other detection techniques, such as X-ray absorption near edge structure (XANES) and scanning electron microscopy (SEM), were also carried out to characterize the sample.

We used the wet chemistry method with different amounts of LiI to prepare LiFePO4 and carbon-coated LiFePO4 (LiFePO4/C) samples. The lithiation process of LiI for preparing the LiFePO4 is proposed. We found that the amount of LiI greatly affected the purities of products. The LiFePO4/C sample showed constant values of current density during potential cycling up to 35 cycles as compared to LiFePO4, suggesting that the LiFePO4/C has better electrochemical performance. The obtained maximum capacity for LiFePO4/C can be approached to the theoretical capacity of 170 mAh/g. Moreover, Brunauer-Emmett-Teller measurements of LiFePO4 and LiFePO4/C showed a surface area of 6.7 and 50 m(2)/g, respectively. It is reasonable to believe that the excellent performance of the compound developed in our work can be attributed to the smaller particle size coated with conductive carbon achieved by the controlling LiI in the sol-gel method.

The structure and histochemistry of sclerotia of Ophiocordyceps sinensis (synonym: Cordyceps sinensis) are described. The remains of the caterpillar epidermis and sometimes setae of the caterpillar were attached to the pigmented layer that is external to the rind of the sclerotium. The outer aerial hyphae and hyphae of the inner medulla were densely interwoven around the epidermis of the caterpillar; these eventually differentiated into the rind of the sclerotium. The medulla of the sclerotium consisted of three intergrading regions of hyphal density: high, low and a region of intermediate hyphal density. All hyphae of the medulla contained large quantities of protein, polysaccharide and polyphosphate; only the region of high hyphal density was rich in beta-1,3 glucans; the center of the sclerotium was almost devoid of hyphae and contained what are most likely the remains of caterpillar tissue. These features are compared with those of sclerotia of other fungi, and their possible significance is discussed.

In this paper, we report the synthesis of carbon coated Li(Mn0.35Co 0.2Fe0.45)PO4 and discuss the effect of Co2P formation during the carbothermal reduction process, which enhances the electrochemical performance of cathode material for lithium ion batteries. It was observed that Co2P was favorably formed in 5% H2/Ar than in Ar atmosphere. The conductivity of Li(Mn0.35Co0.2Fe0.45)PO4/C sintered at 600-800 degrees C in 5% H2/Ar is increased as the temperature is increased. The O K-edge X-ray absorption near edge spectrum (XANES) demonstrates that content of hole carriers is increased in Li(Mn0.35Co0.2Fe0.45)PO4/C as the amount of Co2P increased. We also observed that the capacity of Li(Mn0.35Co0.2Fe0.45)PO4/C is increased with sintering temperature, and it exhibited a maximum capacity of 166 mAh/g at 700 degrees C. It was found that the enhancement in the discharge capacity of sintered Li(Mn0.35Co0.2Fe0.45)PO4/C was as a result of its higher electrical conductivity under 5% H2/Ar atmosphere as compared with Ar atmosphere.

In the present investigation, we report the transformation of alpha-LiVOPO 4 to alpha-Li 3V 2(PO 4) 3, leading to an enhancement of capacity. The alpha-LiVOPO 4 sample was synthesized by a sol-gel method, followed by sintering at 550-650 degrees C in a flow of 5% H 2/Ar. The structural transformation of a triclinic alpha-LiVOPO 4 structure to a monoclinic alpha-Li 3V 2(PO 4) 3 structure was observed at higher sintering temperatures (700-800 degrees C in a flow of 5% H 2/Ar). The alpha-Li 3V 2(PO 4) 3 phase was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermal gravimetric analysis, and X-ray absorption near edge spectrum (XANES) techniques. The valence shift of vanadium ions from +4 to +3 states was observed using in situ XANES experiments at V K-edge. The structural transformation is ascertained by the shape changes in pre-edge and near edge area of X-ray absorption spectrum. It was observed that the capacity was enhanced from 140 mAh/g to 164 mAh/g via structural transformation process of LiVOPO 4 to Li 3V 2(PO 4) 3.

A Synchrotron x-ray source was used for In Situ x-ray diffraction studies during charge on a new LiMg0.125Ti0.125Ni0.75O2 cathode material synthesized by FMC Corp. It had been demonstrated by Gao(1) that this new material has superior thermal stability than LiNiO2 and LiCo0.2Ni0.8O2 at over-charged state. In this current paper, studies on the relationship between the structural changes and thermal stability at over-charged state for these materials are presented. For the fist time, The thermal stability of these materials are related to their structural changes during charge, especially to the formation and lattice constant change of a hexagonal phase (H3). The spectral evidence support our hypothesis that the improvement of thermal stability is obtained by suppressing the formation of H3 phase and reducing the shrinkage of its lattice constant "c" when charged above 4.3 V.

Using synchrotron-based in situ X-ray diffraction, the structural changes of LiCoO2, LiCo0.5Ni0.5O2, and LiNi0.65Co0.25Mg0.05Ti0.05O2 cathode materials during charge in the voltage range of 3.5 to 5.2V have been studied. When a LiCoO2 cathode was charged above 4.5V, a new intermediate phase O1a was observed, before the terminal phase O1 was formed around 4.8V. In the X-ray diffraction spectra for LiCo0.5Ni0.5O2 and LiNi0.65Co0.25Mg0.05Ti0.05O2 cathode materials, Bragg peaks representing the O1 structure were also observed. The amounts of O1 structure formed at the end of charge (5.2V for LiNi0.65Co0.25Mg0.05Ti0.05O2 and 5.0V for LiCo0.5Ni0.5O2) were increased with increasing Co content.

A synchrotron x-ray source was used for In Situ x-ray diffraction studies on cathode materials during charge and discharge. Two new cathode materials, LiNi0.75Mg0.125Ti0.125O2 and LiNi0.65Co0.25Mg0.05Ti0.05O2, were studied in comparison with LiNiO2 and LiCo0.2Ni0.8O2. The relationship between the structural changes and thermal stability at over-charged state has been investigated. For the first time, The thermal stability of these materials are related to their structural changes during charge, especially to the formation of a hexagonal phase H3 with collapsed lattice along "c" axis. A hypothesis is proposed that through suppressing the formation of H3 phase when charged above 4.3 V, the thermal stability of the cathode materials can be improved.

We describe synchroton based X-ray diffraction techniques and issues related to in situ studies of intercalation processes in battery electrodes. We then demonstrate the utility of this technique, through a study of two batches of LixMn2O4 cathode materials. The structural evolution of these spinel materials was monitored in situ during the initial charge of these electrodes in actual battery cells. Significant differences were observed in the two batches, particularly in the intercalation range of x = 0.45 to 0.20. The first-order structural transitions in this region indicated coexistence of two cubic phases in the batch 2 material, whereas the batch 1 material showed suppressed two-phase coexistence. Batch 2 cells also indicated structural evolution in the low-potential region below 3.0 V in contrast to the batch 1 material. Differences in structural evolution between batches of LixMn2O4 could have important ramifications in their cycle life and stability characteristics.

In Situ x-ray diffraction studies on Li{sub x}Mn{sub 2}O{sub 4} spinel cathode materials during charge-discharge cycles were carried out by using a synchrotron as x-ray source. Lithium rich (x = 1.03-1.06) spinel materials obtained from two different sources were studied. Three cubic phases with different lattice constants were observed during charge-discharge cycles in all the samples when a Sufficiently low charge-discharge rate (C/10) was used. There are two regions of two-phase coexistence between these three phases, indicating that both phase transitions are first order. The separation of the Bragg peaks representing these three phases varies from sample to sample and also depends on the charge-discharge rate. These results show that the de-intercalation of lithium in lithium-rich spinel cathode materials proceeds through a series of phase transitions from a lithium-rich phase to a lithium-poor phase and finally to a {lambda}-MnO{sub 2} like cubic phase, rather than through a continuous lattice constant contraction in a single phase.

Hard x rays from a synchrotron source were utilized in diffraction experiments which probed the bulk of electrode materials while they were operating in situ in battery cells. Two technologically relevant electrode materials were examined; an AB2-type anode in a nickel–metal–hydride cell and a LiMn2O4 cathode in a Li-ion ‘‘rocking chair’’ cell. Structural features such as lattice expansions and contractions, phase transitions, and the formation of multiple phases were easily observed as either hydrogen or lithium was electrochemically intercalated in and out of the electrode materials. The relevance of this technique for future studies of battery electrode materials is discussed.

ABSTRACTThe results of an in situ investigation of the structural changes that occur during the operation of working battery electrodes using synchrotron radiation are presented. Two types of electrodes were investigated: an AB2-type Laves phase alloy anode with the composition ZrxTi1-xM2 and a proprietary cell based on a LixMn2O4 spinel compound cathode made by Gould electronics. For the Laves phase alloy compositions with x=0.25 and 0.5 and M=V0.5N1.1Mn0.2Fe0.2 were examined. Cells made from two different batches of LixMn2O4 material were investigated. The relationships between battery performance and structural changes will be discussed. In the later case, we also discuss the role of over-discharging on the LixMn2O4 structure and on battery operation.