Rechargeable-battery chemistry based on lithium oxide growth through nitrate anion redox

Next-generation lithium-battery cathodes often involve the growth of lithium-rich phases, which enable specific capacities that are 2−3 times higher than insertion cathode materials, such as lithium cobalt oxide. Here, we investigated battery chemistry previously deemed irreversible in which lithium oxide, a lithium-rich phase, grows through the reduction of the nitrate anion in a lithium nitrate-based molten salt at 150 °C. Using a suite of independent characterization techniques, we demonstrated that a Ni nanoparticle catalyst enables the reversible growth and dissolution of micrometre-sized lithium oxide crystals through the effective catalysis of nitrate reduction and nitrite oxidation, which results in high cathode areal capacities (~12 mAh cm^(–2)). These results enable a rechargeable battery system that has a full-cell theoretical specific energy of 1,579 Wh kg^(–1), in which a molten nitrate salt serves as both an active material and the electrolyte

A Molten Salt Lithium-Oxygen Battery

Despite the promise of extremely high theoretical capacity (2Li + O_2 ↔ Li_2O_2, 1675 mAh per gram of oxygen), many challenges currently impede development of Li/O_2 battery technology. Finding suitable electrode and electrolyte materials remains the most elusive challenge to date. A radical new approach is to replace volatile, unstable and air-intolerant organic electrolytes common to prior research in the field with alkali metal nitrate molten salt electrolytes and operate the battery above the liquidus temperature (>80 °C). Here we demonstrate an intermediate temperature Li/O_2 battery using a lithium anode, a molten nitrate-based electrolyte (e.g., LiNO_3–KNO_3 eutectic) and a porous carbon O_2 cathode with high energy efficiency (∼95%) and improved rate capability because the discharge product, lithium peroxide, is stable and moderately soluble in the molten salt electrolyte. The results, supported by essential state-of-the-art electrochemical and analytical techniques such as in situ pressure and gas analyses, scanning electron microscopy, rotating disk electrode voltammetry, demonstrate that Li_2O_2 electrochemically forms and decomposes upon cycling with discharge/charge overpotentials as low as 50 mV. We show that the cycle life of such batteries is limited only by carbon reactivity and by the uncontrolled precipitation of Li_2O_2, which eventually becomes electrically disconnected from the O_2 electrode

Jurassic Law: South Carolina\u27s Paleontology and Its Connection with the Legal Field

Many are unaware of South Carolina’s footprint in the paleontology community. Even more are now scratching their heads wondering what paleontology has to do with the law. And yet, there are statutes and regulations governing the excavation, transportation, and preservation of archaeological and paleontological finds. Novice paleontologists—or any future member of the fossilist community or their legal advisors—must check state statutes and regulations before going to collect fossils or artifacts as the law in every state may vary

Repeatability of quantitative sensory testing in healthy cats in a clinical setting with comparison to cats with osteoarthritis

Objectives: The aim of this study was to evaluate the repeatability of quantitative sensory tests (QSTs) in a group of healthy untrained cats (n = 14) and to compare the results with those from cats with osteoarthritis (n = 7). Methods: Peak vertical force (PVF) and vertical impulse were measured on a pressure plate system. Thermal sensitivity was assessed using a temperature-controlled plate at 7°C and 40°C. Individual paw lifts and overall duration of paw lifts were counted and measured for each limb. Paw withdrawal thresholds were measured using manual and electronic von Frey monofilaments (MVF and EVF, respectively) applied to the metacarpal or metatarsal pads. All measurements were repeated twice to assess repeatability of the tests. Results: In healthy cats all tests were moderately repeatable. When compared with cats with osteoarthritis the PVF was significantly higher in healthy hindlimbs in repeat 1 but not in repeat 2. Cats with osteoarthritis of the forelimbs showed a decrease in the frequency of paw lifts on the 7°C plate compared with cats with healthy forelimbs, and the duration of paw lifts was significantly less than healthy forelimbs in the first repeat but not in the second repeat. Osteoarthritic limbs had significantly lower paw withdrawal thresholds with both MVF and EVF than healthy limbs. Conclusions and relevance: QSTs are moderately repeatable in untrained cats. Kinetic gait analysis did not permit differentiation between healthy limbs and those with osteoarthritis, but thermal sensitivity testing (cold) does. Sensory threshold testing can differentiate osteoarthritic and healthy limbs, and may be useful in diagnosis and monitoring of this condition in cats in the clinical setting

Incorporation of a nucleoside analog maps genome repair sites in postmitotic human neurons

Neurons are the longest-lived cells in our bodies and lack DNA replication, which makes them reliant on a limited repertoire of DNA repair mechanisms to maintain genome fidelity. These repair mechanisms decline with age, but we have limited knowledge of how genome instability emerges and what strategies neurons and other long-lived cells may have evolved to protect their genomes over the human life span. A targeted sequencing approach in human embryonic stem cell-induced neurons shows that, in neurons, DNA repair is enriched at well-defined hotspots that protect essential genes. These hotspots are enriched with histone H2A isoforms and RNA binding proteins and are associated with evolutionarily conserved elements of the human genome. These findings provide a basis for understanding genome integrity as it relates to aging and disease in the nervous system