Single-crystal materials have played a unique role in the development of high-performance cathode materials for Li batteries due to their favorable chemomechanical stability. The molten salt ...synthesis method has become one of the most prominent techniques used to synthesize single-crystal layered and spinel materials. In this work, the molten salt synthesis method is used as a technique to tune both the morphology and Mn3+ content of high-voltage LiNi0.5Mn1.5O4 (LNMO) cathodes. The resulting materials are thoroughly characterized by a suite of analytical techniques, including synchrotron X-ray core-level spectroscopy, which are sensitive to the material properties on multiple length scales. The multidimensional characterization allows us to build a materials library according to the molten salt phase diagram as well as to establish the relationship among synthesis, material properties, and battery performance. The results of this work show that the Mn3+ content is primarily dependent on the synthesis temperature and increases as the temperature is increased. The particle morphology is mostly dependent on the composition of the molten salt flux, which can be tailored to obtain well-defined octahedrons enclosed by (111) facets, plates with predominant (112̅) facets, irregularly shaped particles, or mixtures of these. The electrochemical measurements indicate that the Mn3+ content has a larger contribution to the battery performance of LNMO than do morphological characteristics and that a significant amount of Mn3+ could become detrimental to the battery performance. However, with similar Mn3+ contents, morphology still plays a role in influencing the battery cycle life and rate performance. The insights of molten salt synthesis parameters on the formation of LNMO, with deconvolution of the roles of Mn3+ and morphology, are crucial to continuing studies in the rational design of LNMO cathode materials for high-energy Li batteries.
Abstract
Transmission x-ray microscopy (TXM), which can provide morphological and chemical structural information inside of battery component materials at tens of nanometer scale, has become a ...powerful tool in battery research. This article presents a short review of the TXM, including its instrumentation, battery research applications, and the practical sample preparation and data analysis in the TXM applications. A brief discussion on the challenges and opportunities in the TXM applications is presented at the end.
Non-oxidative methane dehydro-aromatization reaction can co-produce hydrogen and benzene effectively on a molybdenum-zeolite based thermochemical catalyst, which is a very promising approach for ...natural-gas upgrading. However, the low methane conversion and aromatics selectivity and weak durability restrain the realistic application for industry. Here, a mechanism for enhancing catalysis activity on methane activation and carbon-carbon bond coupling has been found to promote conversion and selectivity simultaneously by adding platinum-bismuth alloy cluster to form a trimetallic catalyst on zeolite (Pt-Bi/Mo/ZSM-5). This bimetallic alloy cluster has synergistic interaction with molybdenum: the formed CH
from Mo
C on the external surface of zeolite can efficiently move on for C-C coupling on the surface of Pt-Bi particle to produce C
compounds, which are the key intermediates of oligomerization. This pathway is parallel with the catalysis on Mo inside the cage. This catalyst demonstrated 18.7% methane conversion and 69.4% benzene selectivity at 710 °C. With 95% methane/5% nitrogen feedstock, it exhibited robust stability with slow deactivation rate of 9.3% after 2 h and instant recovery of 98.6% activity after regeneration in hydrogen. The enhanced catalytic activity is strongly associated with synergistic interaction with Mo and ligand effects of alloys by extensive mechanism studies and DFT calculation.
The multiscale chemomechanical interplay in lithium‐ion batteries builds up mechanical stress, provokes morphological breakdown, and leads to state of charge heterogeneity. Quantifying the interplay ...in complex composite electrodes with multiscale resolution constitutes a frontier challenge in precisely diagnosing the fading mechanism of batteries. In this study, hard X‐ray phase contrast tomography, capable of nanoprobing thousands of active particles at once, enables an unprecedented statistical analysis of the chemomechanical transformation of composite electrodes under fast charging conditions. The damage heterogeneity is demonstrated to prevail at all length scales, which stems from the unbalanced electron conduction and ionic diffusion, and collectively leads to the nonuniform utilization of active particles spatially and temporally. This study highlights that the statistical mapping of the chemomechanical transformation offers a diagnostic method for the particles utilization and fading, hence could improve electrode formulation for fast‐charging batteries.
Hard X‐ray phase contrast tomography, capable of nano‐probing thousands of active particles at once, enables an unprecedented statistical analysis of the chemomechanical transformation of composite electrodes under fast charging conditions. This study offers a diagnosing method for the particles utilization and fading, hence could improve the electrode formulation for fast‐charging batteries.
There is a serious public health need for better understanding of alcohol use disorder disease mechanisms and for improved treatments. At this writing, only three drugs are approved by the Food and ...Drug Administration as medications to treat alcohol use disorders – disulfiram, naltrexone, and acamprosate. Binge drinking is a form of abusive alcohol drinking defined by the NIAAA as a drinking to blood alcohol levels (BALs)>0.08% during a period of approximately 2h. To model genetic risk for binge-like drinking, we have used selective breeding to create a unique animal model, High Drinking in the Dark (HDID) mice. Behavioral characterization of HDID mice has revealed that HDID mice exhibit behavioral impairment after drinking, withdrawal after a single binge-drinking session, and escalate their intake in response to induction of successive cycles of dependence. Notably, HDID mice do not exhibit altered tastant preference or alcohol clearance rates. We therefore asked whether drugs of known clinical relevance could modulate binge-like ethanol drinking in HDID mice, reasoning that this characterization of HDID responses should inform future use of this genetic animal model for screening and development of novel potential therapeutics.
We tested the efficacy of acamprosate and naltrexone to reduce binge-like drinking in HDID mice. Additionally, we tested the GABAB receptor agonist, baclofen, based on recent pre-clinical and clinical studies demonstrating that it reduces alcohol drinking. We elected not to include disulfiram due to its more limited clinical usage. Mice were tested after acute doses of drugs in the limited-access Drinking in the Dark (DID) paradigm.
HDID mice were sensitive to the effects of acamprosate and baclofen, but not naltrexone. Both drugs reduced binge-like drinking. However, naltrexone failed to reduce drinking in HDID mice. Thus, HDID mice may represent a useful model for screening novel compounds.
•HDID mice offer a novel genetic animal model for binge-like alcohol drinking.•Drinking in the dark can be used to screen novel pharmacotherapies.•Acamprosate and R-baclofen reduce drinking in HDID mice.•Naltrexone does not reduce drinking in HDID mice.
Abstract We have selectively bred mice that reach very high blood ethanol concentrations (BECs) after drinking from a single bottle of 20% ethanol. High Drinking in the Dark (HDID-1) mice drink ...nearly 6 g/kg ethanol in 4 h and reach average BECs of more than 1.0 mg/mL. Previous studies suggest that DID and two-bottle preference for 10% ethanol with continuous access are influenced by many of the same genes. We therefore asked whether HDID-1 mice would differ from the HS/Npt control stock on two-bottle preference drinking. We serially offered mice access to 3–40% ethanol in tap water versus tap water. For ethanol concentrations between 3 and 20%, HDID-1 and HS/Npt controls did not differ in two-bottle preference drinking. At the highest concentrations, the HS/Npt mice drank more than the HDID-1 mice. We also tested the same mice for preference for two concentrations each of quinine, sucrose, and saccharin. Curiously, the mice showed preference ratios (volume of tastant/total fluid drunk) of about 50% for all tastants and concentrations. Thus, neither genotype showed either preference or avoidance for any tastant after high ethanol concentrations. Therefore, we compared naive groups of HDID-1 and HS/Npt mice for tastant preference. Results from this test showed that ethanol-naive mice preferred sweet fluids and avoided quinine but the genotypes did not differ. Finally, we tested HDID-1 and HS mice for an extended period for preference for 15% ethanol versus water during a 2-h access period in the dark. After several weeks, HDID-1 mice consumed significantly more than HS. We conclude that drinking in the dark shows some genetic overlap with other tests of preference drinking, but that the degree of genetic commonality depends on the model used.
Despite acceptance that risk for alcohol-use disorder (AUD) has a large genetic component, the identification of genes underlying various components of risk for AUD has been hampered in humans, in ...part by the heterogeneity of expression of the phenotype. One aspect of AUD is physical dependence. Alcohol withdrawal is a serious consequence of alcohol dependence with multiple symptoms, many of which are seen in multiple species, and can be experienced over a wide-ranging time course.
In the present three studies, we developed a battery of withdrawal tests in mice, examining behavioral symptoms from multiple domains that could be measured over time. To permit eventual use of the battery in different strains of mice, we used male and female mice of a genetically heterogeneous stock developed from intercrossing eight inbred strains.
Withdrawal symptoms were assessed using commonly used tests after administration of ethanol in vapor for 72 continuous hours. We found significant effects of ethanol withdrawal versus air-breathing controls on nearly all symptoms, spanning 4 days following ethanol vapor inhalation. Withdrawal produced hypothermia, greater neurohyperexcitability (seizures and tremor), anxiety-like behaviors using an apparatus (such as reduced transitions between light and dark compartments), anhedonia (reduced sucrose preference), Straub tail, backward walking, and reductions in activity; however, there were no changes in thermal pain sensitivity, hyper-reactivity to handling, or anxiety-like emergence behaviors in other apparatus. Using these data, we constructed a refined battery of withdrawal tests. Individual differences in severity of withdrawal among different tests were weakly correlated at best. This battery should be useful for identifying genetic influences on particular withdrawal behaviors, which should reflect the influences of different constellations of genes.
•Commonly used mouse behavioral tests from multiple behavioral domains reflected the state of withdrawal.•Domains tested: neurohyperexcitability, ataxia,anxiety- and depression-like behaviors, body temperature, thermal pain.•Severity of withdrawal using different measures from different domains was not phenotypically correlated.•Use of an HS stock in development of these behavioral batteries should lead to generalizability to multiple mouse strains.•Withdrawal behaviors from different domains occurred at specific times across a 4-day time course.
Spinel LiNi0.5Mn1.5O4 (LNMO) can adopt two crystallographic structures: an ordered P4332 structure and a disordered Fd3̅m structure. The disordered phase is associated with the reduction of a small ...amount of Mn4+ to Mn3+. LNMO single-crystals likely contain local regions of both ordered and disordered regions, which ensemble-averaged characterizations fail to distinguish. Herein, we employ high-spatial-resolution synchrotron X-ray nanodiffraction techniques to identify lattice distortions and structural defects in LNMO samples with octahedral and plate-like morphologies containing ∼6% and ∼22% of Mn3+, respectively. Differences in properties between the two particles give rise to different distributions of lattice variations, which may indicate differences in phase distributions. Bragg coherent diffraction is also used to observe phase heterogeneities in single grains. Lattice distortions and structural defects could shut down or open up local diffusion pathways for lithium ions, making lithium ion diffusion more complicated and potentially more tortuous than that in a perfect LNMO lattice.
Abstract Displaced intracapsular fractures of the neck of femur are routinely treated in the elderly with either cemented or uncemented hemiarthroplasty. Recent evidence suggests a superior outcome ...with the use of cement, but uncemented prostheses are still employed for those with multiple co-morbidities or particular frailty. In Scotland, the Scottish Intercollegiate Guidelines Network (SIGN) recommendations are used to identify which patients should receive a cemented prosthesis. These are simply based upon the presence of cardiorespiratory disease, particularly in the frail elderly patient. Between January 2007 and June 2010, a total of 1397 patients with neck-of-femur fractures presented to our unit. Retrospective analysis was performed with particular attention given to the rate of postoperative periprosthetic fracture. As many as 546 fractures were treated with hemiarthroplasty, of which 183 were treated with a cemented Exeter Trauma Stem (ETS) and 363 were treated with an uncemented Austin-Moore prosthesis (AMP). At the time of our retrospective analysis, we found that 15 (4%) patients treated with an uncemented prosthesis went on to sustain a periprosthetic fracture. There were no periprosthetic fractures in the cemented group ( p = 0.004). Data analysis by case-note review of those patients sustaining a periprosthetic fracture was then performed. Seven (50%) suffered from confusion secondary to dementia, six (43%) had a history of significant cardiac disease (recent myocardial infarction (MI) or cardiac failure) and two (14%) had known renal impairment. The mean time to fracture after uncemented hemiarthroplasty was 2 years. The majority (80%) were fractures which required further surgery. Revision surgery in these patients was associated with an overall complication rate of 42% (mainly deep infection and haemorrhage requiring transfusion). Two of the patients had a fracture that could be treated conservatively. It is concluded that, in conjunction with the treating senior anaesthetist, cemented implants should be considered in all patients, especially those who are deemed to be frail and with multiple co-morbidities. A periprosthetic fracture rate of 14% at a mean of 2 years after uncemented hemiarthroplasty represents a potentially unacceptable risk for such a frail population. In particular, we feel that the AMP should not be used for treating displaced intracapsular neck-of-femur fractures.
Intermittent access (IA) to an alcohol (ethanol) solution can lead rats to higher ethanol intakes than continuous access, and a recent report showed increased drinking in C57BL/6J mice offered 20% ...ethanol vs. water 3X/week (Prior studies have offered ethanol during 24 h periods, either continuously or intermittently.).
We tested the high-preference C57BL/6J inbred mice: we also studied High Drinking in the Dark (HDID) mice, a line we have selectively bred to reach intoxicating blood ethanol levels after a short period of access to a single bottle of 20% ethanol.
Neither HDID or C57BL/6J male mice offered ethanol every other day during only a 4-h access period showed greater daily intake than mice offered ethanol daily for 4 h. There was a small increase in drinking with 24 h IA in C57BL/6J mice. An experiment with HDID mice and their control heterogeneous stock stock modeled closely after a published study with C57BL/6J mice (Hwa, Chu, Levinson SA et al. Persistent escalation of alcohol drinking in C57BL/6J mice with intermittent access to 20% ethanol. Alcohol Clin Exp Res 2011;35:1938-1947) showed no significant elevation with 24 h IA exposure in either sex of any genotype. Finally, a near replication of the Hwa et al. study showed modestly greater intake in C57BL/6J mice, confirming the efficacy of 24 h IA.
We conclude that 4 h of IA is likely insufficient to elevate drinking in mice. The lack of effect in HDID mice and their controls further suggests that not all genotypes respond to intermittency.
PDF
