Lithium doped N,N-dimethyl pyrrolidinium tetrafluoroborate organic ionic plastic crystal electrolytes for solid state lithium batteries

The organic ionic plastic crystal material N,N-dimethyl pyrrolidinium tetrafluoroborate ([C1mpyr][BF4]) has been mixed with LiBF4 from 0 to 8 wt% and shown to exhibit enhanced ionic conductivity, especially in the higher temperature plastic crystal phases (phases II and I). The materials retain their solid state well above 100 &deg;C with the melt not being observed up to 300 &deg;C. Interestingly the conductivity enhancement is highest with the lowest level of LiBF4 addition in phase II, but then the order of enhancement is reversed in phase I. In all cases, a conductivity drop is observed at the II &rarr; I phase transition (105 &deg;C) which is associated with increased order in the pure matrix, as previously reported, although the conductivity drop is least for the highest LiBF4 amount (8 wt%). The 8 wt% sample displays different conductivity behaviours compared to the lower LiBF4 concentrations, with a sharp increase above 50 &deg;C, which is apparently not related to the formation of an amorphous phase, based on XRD data up to 120 &deg;C. Symmetric cells, Li/OIPC/Li, were prepared and cycled at 50 &deg;C and showed evidence of significant preconditioning with continued cycling, leading to a lower over-potential and a concomitant decrease in the cell resistivity as measured by EIS. An SEM investigation of the Li/OIPC interfaces before and after cycling suggested significant grain refinement was responsible for the decrease in cell resistance upon cycling, possibly as a result of an increased grain boundary phase.<br /

HRCT Features of Dermatomyositis-/Polymyositis- Associated Interstitial Lung Disease

Objective: To evaluate high-resolution computed tomography (HRCT) features of dermatomyositis-/polymyositis- associated interstitial lung disease (DM/PM-ILD). Methods: We retrospectively reviewed the HRCT images of 148 patients with DM/PM-ILD at the First Affiliated Hospital of Xi’an Jiaotong University between Jan. 1, 2014, and Dec. 31, 2019. Results: The HRCT features of DM/PM-ILD were characterized by ground-glass opacities (GGO) (87.2%, 123/141), interlobular septal thickening (78.0%, 110/141), intralobular interstitial thickening (63.8%, 90/141), consolidation (29.1%, 41/141), subpleural lines (26.2%, 37/141), traction bronchiectasis (19.9%, 28/141), and honeycombing (3.5%, 5/141). Pneumomediastinum (3), pleural effusion (15), and pericardial effusion (18) were also observed. The two main radiological patterns were non-specific interstitial pneumonia (NSIP) and organism pneumonia (OP). Conclusion: HRCT features of DM/PM-ILD are heterogeneous, with various radiological patterns. Mastering the main characteristics of HRCT manifestation and the radiological patterns of DM/PM-ILD will be helpful for early identification and timely treatment

DIFFERENT CONCENTRATIONS OF SIJUNZI DECOCTION INHIBIT PROLIFERATION AND INDUCE APOPTOSIS OF HUMAN GASTRIC CANCER SGC-7901 SIDE POPULATION

Background: SD is a traditional Chinese medicine which composed of Ginseng, Atractylodes, Poria and Licorice. It is one of the commonly used Chinese traditional medicines that showed anti-gastric cancer activity in clinical studies. Previous evidence demonstrated SD parties (Ginseng, Atractylodes, Poria, Licorice) can inhibit proliferation and induced apoptosis for gastric cancer cell. In order to further investigate the anticancer effect of SD in gastric cancer, we observed the effects of different concentrations of SD on proliferation and apoptosis of SP of human gastric cancer SGC-7901. Materials and Methods: 1. SGC-7901 side population cells were sorted through flow cytometry. 2. To detect the changes of proliferation of SP and NSP before and after the intervention of serum containing different concentrations of SD using cck-8 method. 3. To detect the changes of cell cycle and apoptosis of SP and NSP before and after the intervention of serum containing different concentrations of SD through flow cytometry. 4. To detect the effects of serum containing different concentrations of SD on apoptosis-related proteins Bax and Bcl-2 of SP and NSP before and after the intervention by western-blot. Results: It was found that different concentrations of SD serum treatments inhibited cell proliferation in a time-dependent and concentration-dependent manner. Compared with the control group (normal saline treatment), there were increase in G1/G0 phase population of SP and NSP, and decrease in G2/M and S phase population (

Dental resin monomer enables unique NbO2/carbon lithium‐ion battery negative electrode with exceptional performance

Niobium dioxide (NbO2) features a high theoretical capacity and an outstanding electron conductivity, which makes it a promising alternative to the commercial graphite negative electrode. However, studies on NbO2 based lithium-ion battery negative electrodes have been rarely reported. In the present work, NbO2 nanoparticles homogeneously embedded in a carbon matrix are synthesized through calcination using a dental resin monomer (bisphenol A glycidyl dimethacrylate, Bis-GMA) as the solvent and a carbon source and niobium ethoxide (NbETO) as the precursor. It is revealed that a low Bis-GMA/NbETO mass ratio (from 1:1 to 1:2) enables the conversion of Nb (V) to Nb (IV) due to increased porosity induced by an alcoholysis reaction between the NbETO and Bis-GMA. The as-prepared NbO2/carbon nanohybrid delivers a reversible capacity of 225 mAh g−1 after 500 cycles at a 1 C rate with a Coulombic efficiency of more than 99.4% in the cycles. Various experimental and theoretical approaches including solid state nuclear magnetic resonance, ex situ X-ray diffraction, differential electrochemical mass spectrometry, and density functional theory are utilized to understand the fundamental lithiation/delithiation mechanisms of the NbO2/carbon nanohybrid. The results suggest that the NbO2/carbon nanohybrid bearing high capacity, long cycle life, and low gas evolution is promising for lithium storage applications

What Triggers Oxygen Loss in Oxygen Redox Cathode Materials?

It is possible to increase the charge capacity of transition-metal (TM) oxide cathodes in alkali-ion batteries by invoking redox reactions on the oxygen. However, oxygen loss often occurs. To explore what affects oxygen loss in oxygen redox materials, we have compared two analogous Na-ion cathodes, P2-Na0.67Mg0.28Mn0.72O2 and P2-Na0.78Li0.25Mn0.75O2. On charging to 4.5 V, >0.4e– are removed from the oxide ions of these materials, but neither compound exhibits oxygen loss. Li is retained in P2-Na0.78Li0.25Mn0.75O2 but displaced from the TM to the alkali metal layers, showing that vacancies in the TM layers, which also occur in other oxygen redox compounds that exhibit oxygen loss such as Li[Li0.2Ni0.2Mn0.6]O2, are not a trigger for oxygen loss. On charging at 5 V, P2-Na0.78Li0.25Mn0.75O2 exhibits oxygen loss, whereas P2-Na0.67Mg0.28Mn0.72O2 does not. Under these conditions, both Na+ and Li+ are removed from P2-Na0.78Li0.25Mn0.75O2, resulting in underbonded oxygen (fewer than 3 cations coordinating oxygen) and surface-localized O loss. In contrast, for P2-Na0.67Mg0.28Mn0.72O2, oxygen remains coordinated by at least 2 Mn4+ and 1 Mg2+ ions, stabilizing the oxygen and avoiding oxygen loss

Oxygen redox chemistry without excess alkali-metal ions in Na2/3_{2/3}[Mg0.28_{0.28}Mn0.72_{0.72}]O2_2

The search for improved energy-storage materials has revealed Li- and Na-rich intercalation compounds as promising high-capacity cathodes. They exhibit capacities in excess of what would be expected from alkali-ion removal/reinsertion and charge compensation by transition-metal (TM) ions. The additional capacity is provided through charge compensation by oxygen redox chemistry and some oxygen loss. It has been reported previously that oxygen redox occurs in O 2$p$ orbitals that interact with alkali ions in the TM and alkali-ion layers (that is, oxygen redox occurs in compounds containing Li$^+$–O(2$p$)–Li$^+$ interactions). Na$_{2/3}$[Mg$_{0.28}$Mn$_{0.72}$]O$_2$ exhibits an excess capacity and here we show that this is caused by oxygen redox, even though Mg$^{2+}$ resides in the TM layers rather than alkali-metal (AM) ions, which demonstrates that excess AM ions are not required to activate oxygen redox. We also show that, unlike the alkali-rich compounds, Na$_{2/3}$[Mg$_{0.28}$Mn$_{0.72}$]O$_2$ does not lose oxygen. The extraction of alkali ions from the alkali and TM layers in the alkali-rich compounds results in severely underbonded oxygen, which promotes oxygen loss, whereas Mg$^{2+}$ remains in Na$_{2/3}$[Mg$_{0.28}$Mn$_{0.72}$]O$_2$, which stabilizes oxygen

Organic Ionic Plastic Crystals as solid electrolytes for lithium batteries

Organic Ionic Plastic Crystals (OIPCs) are increasingly drawing attention as a new type of solid-state electrolyte for lithium rechargeable batteries, because they can essentially relieve the safety concerns of the present commercial lithium batteries based on organic and flammable solvents and thus pave the way towards more robust energy storage solutions for electric vehicles and power grids. However, although significant progress has been made towards the realisation of practical OIPC-based solid electrolytes, the lack of thorough fundamental understanding of their properties, especially the nature of their ionic motion and transport and the effects of Li salt addition, has limited the development of prototype lithium cells using OIPC-based electrolytes. This PhD thesis therefore has three goals: 1) to obtain more insights into the fundamentals of the materials, especially their phase-dependent plastic crystal behaviour; 2) to under- stand the effects of the addition of Li ions on the structure and dynamics of OIPC matrices; 3) to demonstrate prototype Li cells with OIPC-based electrolytes operating at ambient temperature. For Goal 1, two recently synthesised phosphonium cation-based OIPCs, i. e. diethyl(methyl)(isobutyl)phosphonium hexafluorophosphate ([P1224][PF6]) and triethyl(methyl)phosphonium bis(fluorosulfonyl)imide ([P1222][FSI]) were investigated by a combination of analytical methods and theoretical simulations/calculations. The evolution of the motions of the cations and the anions in different phases of both plastic crystals was examined, and models proposed to explain the strongly phase-dependent ionic conductivities of these OIPCs. Cooperative motion of cations and anions was proposed for [P1222][FSI] at a particular temperature range, in which some unusual phase behaviour was observed. For Goal 2, molecular dynamics simulations of the effects of lithium salt addition to a model plastic crystal, tetramethylammonium dicyanamide ([N1111][DCA]) were performed. Cluster formation between Li ions and anions was found: Li-DCA clusters enhance the mobility of the ions that are not in the clusters. This is a somewhat surprising atomic-level explanation of how doped Li ions in the OIPC enhance its ion transport properties. For Goal 3, the electrochemical properties of triisobutyl(methyl) phosphonium bis(fluorosulfonyl) imide ([P1444][FSI]) were examined, and this plastic crystal was used to build prototypical Li metal cells. These cells showed, for the first time, practical cell performance (ca. 160 mA h g-1 discharge capacity achieved at 0.1 C) at ambient temperature. The main contributions of this thesis to the field are 1) proposing new models of the ionic motions of OIPCs with respect to their phase behaviour 2) showing the value of the combined analytical and theoretical methodology in studying OIPCs; 3) demonstrating promising Li cell performance with an OIPC-based electrolyte at ambient temperature