RESUMEN
The stability of high-energy-density lithium metal batteries depends on the uniformity of solid electrolyte interphase (SEI) on lithium metal anodes. Rationally improving SEI uniformity is hindered by poorly understanding the effect of structure and components of SEI on its uniformity. Herein, a bilayer structure of SEI formed by isosorbide dinitrate (ISDN) additives in localized high-concentration electrolytes was demonstrated to improve SEI uniformity. In the bilayer SEI, LiNx Oy generated by ISDN occupies top layer and LiF dominates bottom layer next to anode. The uniformity of lithium deposition is remarkably improved with the bilayer SEI, mitigating the consumption rate of active lithium and electrolytes. The cycle life of lithium metal batteries with bilayer SEI is three times as that with common anion-derived SEI under practical conditions. A prototype lithium metal pouch cell of 430â Wh kg-1 undergoes 173â cycles. This work demonstrates the effect of a reasonable structure of SEI on reforming SEI uniformity.
RESUMEN
Lithium-sulfur (Li-S) batteries have great potential as high-energy-density energy storage devices. Electrocatalysts are widely adopted to accelerate the cathodic sulfur redox kinetics. The interactions among the electrocatalysts, solvents, and lithium salts significantly determine the actual performance of working Li-S batteries. Herein, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), a commonly used lithium salt, is identified to aggravate surface gelation on the MoS2 electrocatalyst. In detail, the trifluoromethanesulfonyl group in LiTFSI interacts with the Lewis acidic sites on the MoS2 electrocatalyst to generate an electron-deficient center. The electron-deficient center with high Lewis acidity triggers cationic polymerization of the 1,3-dioxolane solvent and generates a surface gel layer that reduces the electrocatalytic activity. To address the above issue, Lewis basic salt lithium iodide (LiI) is introduced to block the interaction between LiTFSI and MoS2 and inhibit the surface gelation. Consequently, the Li-S batteries with the MoS2 electrocatalyst and the LiI additive realize an ultrahigh actual energy density of 416 W h kg-1 at the pouch cell level. This work affords an effective lithium salt to boost the electrocatalytic activity in practical working Li-S batteries and deepens the fundamental understanding of the interactions among electrocatalysts, solvents, and salts in energy storage systems.
RESUMEN
Advanced electrolyte design is essential for building high-energy-density lithium (Li) batteries, and introducing anions into the Li+ solvation sheaths has been widely demonstrated as a promising strategy. However, a fundamental understanding of the critical role of anions in such electrolytes is very lacking. Herein, the anionic chemistry in regulating the electrolyte structure and stability is probed by combining computational and experimental approaches. Based on a comprehensive analysis of the lowest unoccupied molecular orbitals, the solvents and anions in Li+ solvation sheaths exhibit enhanced and decreased reductive stability compared with free counterparts, respectively, which agrees with both calculated and experimental results of reduction potentials. Accordingly, new strategies are proposed to build stable electrolytes based on the established anionic chemistry. This work unveils the mysterious anionic chemistry in regulating the structure-function relationship of electrolytes and contributes to a rational design of advanced electrolytes for practical Li metal batteries.
RESUMEN
Serious safety risks caused by the high reactivity of lithium metal against electrolytes severely hamper the practicability of lithium metal batteries. By introducing unique polymerization site and more fluoride substitution, we built an in situ formed polymer-rich solid electrolyte interphase upon lithium anode to improve battery safety. The fluorine-rich and hydrogen-free polymer exhibits high thermal stability, which effectively reduces the continuous exothermic reaction between electrolyte and anode/cathode. As a result, the critical temperature for thermal safety of 1.0â Ah lithium-LiNi0.5 Co0.2 Mn0.3 O2 pouch cell can be increased from 143.2 °C to 174.2 °C. The more dangerous "ignition" point of lithium metal batteries, the starting temperature of battery thermal runaway, has been dramatically raised from 240.0 °C to 338.0 °C. This work affords novel strategies upon electrolyte design, aiming to pave the way for high-energy-density and thermally safe lithium metal batteries.
RESUMEN
The lifespan of practical lithium (Li)-metal batteries is severely hindered by the instability of Li-metal anodes. Fluorinated solid electrolyte interphase (SEI) emerges as a promising strategy to improve the stability of Li-metal anodes. The rational design of fluorinated molecules is pivotal to construct fluorinated SEI. Herein, design principles of fluorinated molecules are proposed. Fluoroalkyl (-CF2 CF2 -) is selected as an enriched F reservoir and the defluorination of the C-F bond is driven by leaving groups on ß-sites. An activated fluoroalkyl molecule (AFA), 2,2,3,3-tetrafluorobutane-1,4-diol dinitrate is unprecedentedly proposed to render fast and complete defluorination and generate uniform fluorinated SEI on Li-metal anodes. In Li-sulfur (Li-S) batteries under practical conditions, the fluorinated SEI constructed by AFA undergoes 183â cycles, which is three times the SEI formed by LiNO3 . Furthermore, a Li-S pouch cell of 360â Wh kg-1 delivers 25â cycles with AFA. This work demonstrates rational molecular design principles of fluorinated molecules to construct fluorinated SEI for practical Li-metal batteries.
RESUMEN
The performance of rechargeable lithium (Li) batteries is highly correlated with the structure of solid electrolyte interphase (SEI). The properties of a working anode are vital factors in determining the structure of SEI; however, the correspondingly poor understanding hinders the rational regulation of SEI. Herein, the electrode potential and anode material, two critical properties of an anode, in dictating the structural evolution of SEI were investigated theoretically and experimentally. The anode potential is identified as a crucial role in dictating the SEI structure. The anode potential determines the reduction products in the electrolyte, ultimately giving rise to the mosaic and bilayer SEI structure at high and low potential, respectively. In contrast, the anode material does not cause a significant change in the SEI structure. This work discloses the crucial role of electrode potential in dictating SEI structure and provides rational guidance to regulate SEI structure.
RESUMEN
The lifespan of high-energy-density lithium metal batteries (LMBs) is hindered by heterogeneous solid electrolyte interphase (SEI). The rational design of electrolytes is strongly considered to obtain uniform SEI in working batteries. Herein, a modification of nitrate ion (NO3 - ) is proposed and validated to improve the homogeneity of the SEI in practical LMBs. NO3 - is connected to an ether-based moiety to form isosorbide dinitrate (ISDN) to break the resonance structure of NO3 - and improve the reducibility. The decomposition of non-resonant -NO3 in ISDN enriches SEI with abundant LiNx Oy and induces uniform lithium deposition. Lithium-sulfur batteries with ISDN additives deliver a capacity retention of 83.7 % for 100 cycles compared with rapid decay with LiNO3 after 55 cycles. Moreover, lithium-sulfur pouch cells with ISDN additives provide a specific energy of 319â Wh kg-1 and undergo 20 cycles. This work provides a realistic reference in designing additives to modify the SEI for stabilizing LMBs.
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High-energy-density lithium (Li) metal batteries suffer from a short lifespan owing to apparently ceaseless inactive Li accumulation, which is accompanied by the consumption of electrolyte and active Li reservoir, seriously deteriorating the cyclability of batteries. Herein, a triiodide/iodide (I3 - /I- ) redox couple initiated by stannic iodide (SnI4 ) is demonstrated to reclaim inactive Li. The reduction of I3 - converts inactive Li into soluble LiI, which then diffuses to the cathode side. The oxidation of LiI by the delithiated cathode transforms cathode into the lithiation state and regenerates I3 - , reclaiming Li ion from inactive Li. The regenerated I3 - engages the further redox reactions. Furthermore, the formation of Sn mitigates the corrosion of I3 - on active Li reservoir sacrificially. In working Li | LiNi0.5 Co0.2 Mn0.3 O2 batteries, the accumulated inactive Li is significantly reclaimed by the reversible I3 - /I- redox couple, improving the lifespan of batteries by twice. This work initiates a creative solution to reclaim inactive Li for prolonging the lifespan of practical Li metal batteries.
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Voltage-gated calcium channel (Ca(v))2.2 (N-type calcium channels) are key components in nociceptive transmission pathways. Ziconotide, a state-independent peptide inhibitor of Ca(v)2.2 channels, is efficacious in treating refractory pain but exhibits a narrow therapeutic window and must be administered intrathecally. We have discovered an N-triazole oxindole, (3R)-5-(3-chloro-4-fluorophenyl)-3-methyl-3-(pyrimidin-5-ylmethyl)-1-(1H-1,2,4-triazol-3-yl)-1,3-dihydro-2H-indol-2-one (TROX-1), as a small-molecule, state-dependent blocker of Ca(v)2 channels, and we investigated the therapeutic advantages of this compound for analgesia. TROX-1 preferentially inhibited potassium-triggered calcium influx through recombinant Ca(v)2.2 channels under depolarized conditions (IC(50) = 0.27 microM) compared with hyperpolarized conditions (IC(50) > 20 microM). In rat dorsal root ganglion (DRG) neurons, TROX-1 inhibited omega-conotoxin GVIA-sensitive calcium currents (Ca(v)2.2 channel currents), with greater potency under depolarized conditions (IC(50) = 0.4 microM) than under hyperpolarized conditions (IC(50) = 2.6 microM), indicating state-dependent Ca(v)2.2 channel block of native as well as recombinant channels. TROX-1 fully blocked calcium influx mediated by a mixture of Ca(v)2 channels in calcium imaging experiments in rat DRG neurons, indicating additional block of all Ca(v)2 family channels. TROX-1 reversed inflammatory-induced hyperalgesia with maximal effects equivalent to nonsteroidal anti-inflammatory drugs, and it reversed nerve injury-induced allodynia to the same extent as pregabalin and duloxetine. In contrast, no significant reversal of hyperalgesia was observed in Ca(v)2.2 gene-deleted mice. Mild impairment of motor function in the Rotarod test and cardiovascular functions were observed at 20- to 40-fold higher plasma concentrations than required for analgesic activities. TROX-1 demonstrates that an orally available state-dependent Ca(v)2 channel blocker may achieve a therapeutic window suitable for the treatment of chronic pain.
Asunto(s)
Analgésicos/farmacología , Bloqueadores de los Canales de Calcio/farmacología , Canales de Calcio Tipo N/fisiología , Indoles/farmacología , Triazoles/farmacología , Analgésicos/efectos adversos , Analgésicos/farmacocinética , Animales , Barorreflejo/efectos de los fármacos , Disponibilidad Biológica , Bloqueadores de los Canales de Calcio/efectos adversos , Bloqueadores de los Canales de Calcio/farmacocinética , Canales de Calcio Tipo N/genética , Canales de Calcio Tipo R/fisiología , Proteínas de Transporte de Catión/fisiología , Línea Celular , Perros , Ganglios Espinales/efectos de los fármacos , Ganglios Espinales/fisiología , Hiperalgesia/tratamiento farmacológico , Hipotensión Ortostática/inducido químicamente , Indoles/efectos adversos , Indoles/farmacocinética , Masculino , Ratones , Ratones Noqueados , Neuronas/efectos de los fármacos , Neuronas/fisiología , Dolor/tratamiento farmacológico , Dolor/etiología , Técnicas de Placa-Clamp , Ratas , Ratas Sprague-Dawley , Triazoles/efectos adversos , Triazoles/farmacocinéticaRESUMEN
BACKGROUND: Nitric oxide donors are widely used to treat cardiovascular disease, but their major limitation is the development of tolerance, a multifactorial process to which the in vivo release of nitric oxide is thought to contribute. Here we describe the preclinical and clinical results of a translational drug development effort to create a next-generation nitric oxide donor with improved pharmacokinetic properties and a unique mechanism of nitric oxide release through CYP3A4 metabolism that was designed to circumvent the development of tolerance. METHODS AND RESULTS: Single- and multiple-dose studies in telemetered dogs showed that MK-8150 induced robust blood-pressure lowering that was sustained over 14 days. The molecule was safe and well tolerated in humans, and single doses reduced systolic blood pressure by 5 to 20 mm Hg in hypertensive patients. Multiple-dose studies in hypertensive patients showed that the blood-pressure-lowering effect diminished after 10 days, and 28-day studies showed that the hemodynamic effects were completely lost by day 28, even when the dose of MK-8150 was increased during the dosing period. CONCLUSIONS: The novel nitric oxide donor MK-8150 induced significant blood-pressure lowering in dogs and humans for up to 14 days. However, despite a unique mechanism of nitric oxide release mediated by CYP3A4 metabolism, tolerance developed over 28 days, suggesting that tolerance to nitric oxide donors is multifactorial and cannot be overcome solely through altered in vivo release of nitric oxide. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifiers: NCT01590810 and NCT01656408.
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Presión Sanguínea/efectos de los fármacos , Hipertensión/tratamiento farmacológico , Donantes de Óxido Nítrico/farmacología , Triazenos/farmacología , Adolescente , Adulto , Anciano , Animales , GMP Cíclico/metabolismo , Perros , Humanos , Técnicas In Vitro , Túbulos Renales Proximales/citología , Masculino , Persona de Mediana Edad , Donantes de Óxido Nítrico/uso terapéutico , Triazenos/uso terapéutico , Adulto JovenRESUMEN
We report the investigation of sulfonamide-derived Cav2.2 inhibitors to address drug-metabolism liabilities with this lead class of analgesics. Modification of the benzamide substituent provided improvements in both potency and selectivity. However, we discovered that formation of the persistent 3-(trifluoromethyl)benzenesulfonamide metabolite was an endemic problem in the sulfonamide series and that the replacement of the center aminopiperidine scaffold failed to prevent this metabolic pathway. This issue was eventually addressed by application of a bioisostere strategy. The new gem-dimethyl sulfone series retained Cav2.2 potency without the liability of the circulating sulfonamide metabolite.
RESUMEN
The voltage-gated calcium channel Ca(v)2.2 (N-type calcium channel) is a critical regulator of synaptic transmission and has emerged as an attractive target for the treatment of chronic pain. We report here the discovery of sulfonamide-derived, state-dependent inhibitors of Ca(v)2.2. In particular, 19 is an inhibitor of Ca(v)2.2 that is selective over cardiac ion channels, with a good preclinical PK and biodistribution profile. This compound exhibits dose-dependent efficacy in preclinical models of inflammatory hyperalgesia and neuropathic allodynia and is devoid of ancillary cardiovascular or CNS pharmacology at the doses tested. Importantly, 19 exhibited no efficacy in Ca(v)2.2 gene-deleted mice. The discovery of metabolite 26 confounds further development of members of this aminopiperidine sulfonamide series. This discovery also suggests specific structural liabilities of this class of compounds that must be addressed.
Asunto(s)
Bloqueadores de los Canales de Calcio/farmacología , Canales de Calcio Tipo N/química , Canales de Calcio Tipo N/fisiología , Dolor Crónico/tratamiento farmacológico , Hiperalgesia/tratamiento farmacológico , Inflamación/tratamiento farmacológico , Neuralgia/tratamiento farmacológico , Piperidinas/farmacología , Sulfonamidas/farmacología , Animales , Bloqueadores de los Canales de Calcio/síntesis química , Bloqueadores de los Canales de Calcio/farmacocinética , Canales de Calcio Tipo N/metabolismo , Células Cultivadas , Perros , Humanos , Ratones , Ratones Noqueados , Microsomas Hepáticos/efectos de los fármacos , Técnicas de Placa-Clamp , Piperidinas/síntesis química , Piperidinas/farmacocinética , Ratas , Ratas Sprague-Dawley , Sulfonamidas/síntesis química , Sulfonamidas/farmacocinética , Distribución TisularRESUMEN
OBJECTIVE: To evaluate the effect of using cone-beam computed tomography (CBCT) and dental operating microscope (DOM) in treating maxillary molars containing bifurcative canals buccally. METHODS: 304 endodontically treated maxillary molars (159 maxillary first molars and 145 maxillary second molars) were included. After preparing access to pulp chamber, the number of canal orifices and location in the pulp chamber floor of each tooth were recorded. For those teeth with bifurcative canals buccally confirmed by preoperative radiographs, the root canals were negotiated by naked eyes firstly, then under DOM according CBCT results. Following working length determination, the root canals were prepared by step-down technique and obturated with cold lateral condensation technique. The efficiency was evaluated with radiographs before, during and after operation. RESULTS: In 304 maxillary molars, 51 molars were found to have two canal orifices (buccal one and palatal one) in the pulp floor, 30 bifurcative canals buccally (8 upper first molars and 22 upper second molars) were found. CBCT information indicated the level of bifurcation in buccal canals were 3-8 mm under the pulp chamber floors. In 30 maxillary molars, 7 teeth treated by X-rays and eyes could be negotiated, 22 teeth treated by CBCT and DOM could be negotiated and were well instrumented and filled by evaluating with radiographs during and after operation, 8 teeth with deep divergent MB2 canals or calcified canal could not be negotiated. CONCLUSION: Operative field can be located precisely by CBCT and dental operating microscope that could be effective method in treating these sort of canals.
Asunto(s)
Tomografía Computarizada de Haz Cónico , Maxilar , Pulpa Dental , Cavidad Pulpar , Humanos , Microscopía , Diente Molar , Diente , Raíz del DienteRESUMEN
It has been shown that peripheral chemoreceptor sensitivity is enhanced in both clinical and experimental heart failure (HF) and that impairment of nitric oxide (NO) production contributes to this enhancement. In order to understand the cellular mechanisms associated with the alterations of chemoreceptor function and the actions of NO in the carotid body (CB), we compared the outward K+ currents (IK) of glomus cells in sham rabbits with that in HF rabbits and monitored the effects of NO on these currents. Ik was measured in glomus cells using conventional and perforated whole-cell configurations. IK was attenuated in glomus cells of HF rabbits, and their resting membrane potentials (-34.7 +/- 1.0 mV) were depolarized as compared with those in sham rabbits (-47.2 +/- 1.9 mV). The selective Ca(2+)-dependent K+ channel (KCa) blocker iberiotoxin (IbTx, 100 nm) reduced IK in glomus cells from sham rabbits, but had no effect on IK from HF rabbits. In perforated whole-cell mode, the NO donor SNAP (100 microm) increased IK in glomus cells from HF rabbits to a greater extent than that in sham rabbits (P < 0.01), and IbTx inhibited the effects of SNAP. However, in conventional whole-cell mode, SNAP had no effect. N omega-nitro-L-arginine (L-NNA, NO synthase inhibitor) decreased Ik in sham rabbits but not in HF rabbits. The guanylate cyclase inhibitor 1H-[1,2,4]oxadiazole[4,3-a]quinoxalin-1-one (ODQ) inhibited the effect of SNAP on Ik. These results demonstrate that IK is reduced in CB glomus cells from HF rabbits. This effect is due mainly to the suppression of KCa channel activity caused by decreased availability of NO. In addition, intracellular cGMP is necessary for the KCa channel modulation by NO.
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Cuerpos Aórticos/fisiología , Cuerpo Carotídeo/fisiología , Insuficiencia Cardíaca/fisiopatología , Óxido Nítrico/fisiología , Canales de Potasio/fisiología , Animales , Cuerpos Aórticos/efectos de los fármacos , Cuerpo Carotídeo/efectos de los fármacos , Masculino , Donantes de Óxido Nítrico/farmacología , Bloqueadores de los Canales de Potasio/farmacología , ConejosRESUMEN
Structurally modified 3-(N-benzylamino)propylphosphonic acid S1P receptor agonists that maintain affinity for S1P1, and have decreased affinity for S1P3 are efficacious, but exhibit decreased acute cardiovascular toxicity in rodents than do nonselective agonists.