Search

The article informs about the Li-air battery that leverages the advantages of both organic and inorganic electrolytes in a composite solid-state matrix at room temperature. Topics include the gain energy capacity from using a stable solid-state electrolyte with high ionic conductivity and a catalyzed gas diffusion layer; and composite material made of a silane coupling agent and a Li superionic conductor material in a matrix of trifluoromethane sulfonyl imide solubilized in polyethylene oxide.

Redox mediators have been widely applied to reduce the charge overpotentials of lithium--oxygen (Li-O2) batteries. Here, we reveal the critical role of redox mediator in suppressing the charging instability of Li-O2 batteries. Using high temporal resolution online electrochemical mass spectrometry, we show that charging with redox mediators (using lithium bromide as a model system) significantly reduces parasitic gas evolution and improves oxygen recovery efficiency. Using redox mediator transforms the charge reactions from electrochemical pathways to chemical pathways, which unexpectedly bypasses the formation of highly reactive intermediates upon electro-oxidation of lithium peroxide (Li2O2). Such transformation reduces self-amplifying degradation reactions of electrode and electrolyte in Li-O2 cells. We further show that the improved stability associated with the redox mediator is much more pronounced at higher charging rates, owing to fast charge-transfer kinetics of the redox mediator. Together, we show that employing redox mediator not only reduces the charge overpotential but also suppresses side reactions of Li-O2 cells with improved charging rate. Our work demonstrates that transforming electro-oxidation of Li2O2 to chemical oxidation of Li2O2 is a promising strategy to simultaneously mitigate charging side reactions and achieve low overpotential for the Li-O2 batteries. [ABSTRACT FROM AUTHOR]

We report the intrinsic oxygen reduction reaction (ORR) activity of polycrystalline palladium, platinum, ruthenium, gold, and glassy carbon surfaces in 0.1 M LiClO4 1,2-dimethoxyethane via rotating disk electrode measurements. The nonaqueous Li+-ORR activity of these surfaces primarily correlates to oxygen adsorption energy, forming a "volcano-type" trend. The activity trend found on the polycrystalline surfaces was in good agreement with the trend in the discharge voltage of Li-O2 cells catalyzed by nanoparticle catalysts. Our findings provide insights into Li+-ORR mechanisms in nonaqueous media and design of efficient air electrodes for Li-air battery applications. [ABSTRACT FROM AUTHOR]

“AlPO4”-coated LiCoO2was shown to exhibit markedly improved capacity retention and reduced impedance growth relative to bare “LiCoO2” upon cycling to 4.7 V. Scanning electron microscopy imaging showed that the surfaces of the cycled bare “LiCoO2” particles remained very smooth whereas there were many newly formed patches distributed on the surfaces of the cycled coated particles. X-ray powder diffraction analyses revealed that select peak broadening was observed for cycled bare electrodes suggesting that structural damage to LixCoO2was introduced upon cycling. In contrast, no apparent structural changes to LixCoO2were found for cycled coated electrodes. Pristine and cycled bare and “AlPO4”-coated LiCoO2electrodes were studied by X-ray photoelectron spectroscopy. No significant change was detected in the surface chemistry of Co for cycled bare electrodes, but surface LiF and LixPFyOzcomponents were found to considerably increase during cycling, which led to partial surface coverage of LixCoO2. A very small amount of Co-containing oxyfluoride species was detected on the cycled bare electrodes while considerable amounts of Co-containing and Al-containing fluorides and/or oxyfluorides and species such as PFx(OH)ywere found on the cycled coated electrodes, which completely covered the surfaces of the LixCoO2particles. The mechanism responsible for the enhanced cycling stability and reduced impedance of coated relative to bare electrodes is discussed in detail. [ABSTRACT FROM AUTHOR]

PtAu nanoparticles (NPs) were shown to strongly enhance the kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in rechargeable Li-O2 cells. Li-O2 cells with PtAu/C were found to exhibit the highest round-trip efficiency reported to date. During ORR via xLi+ + O2 + xe- → LixO2, the discharge voltage with PtAu/C was considerably higher than that of pure carbon and comparable to that of Au/C. During OER via LixO2 → xLi+ + O2 + xe-, the charge voltages with PtAu/C fell in the range from 3.4 to 3.8 VLi, which is slightly lower than obtained with Pt. It is hypothesized that PtAu NPs exhibit bifunctional catalytic activity, having surface Au and Pt atoms primarily responsible for ORR and OER kinetics in Li-O2 cells, respectively. [ABSTRACT FROM AUTHOR]

Nonaqueous redox flow battery (RFB) is a promising technology to improve the energy density of RFBs for both stationary grid energy storage and electric vehicle applications. Despite tremendous advancement made in high-capacity flow posolyte, lithium metal has been dominantly exploited as a nonflowable counter electrode in reported lithium-based RFBs to date due to the lack of efficient and high-capacity flow negolyte. Here, we report a silicon-carbon nanocomposite semi-solid negolyte, achieving a high reversible capacity (>1200 mAh g-1) and stable cycle life (>100 cycles). A facile process of incipient wetness impregnation followed by polymerization/carbonization is developed to synthesize monodispersed Si-C nanocomposite with ultrathin graphitic carbon coating. Exploiting Si-C nanocomposite as the negolyte effectively suppresses the volume change of Si particles and enhances the electrical conductivity of the negolyte. Coupling with highly concentrated LiI (5.0 M), we demonstrate the first lithium metal-free Si-based negolyte in a full all-flow cell configuration with a stable cycle life (>60 cycles), high Coulombic efficiency (>90%), and the highest full cell voltage (3.0 V) reported for Li metal-free RFBs. Our successful demonstration of lithium metal-free all-flow battery highlights the promising potential of Si-based negolyte to replace lithium metal for high-energy-density RFBs. [ABSTRACT FROM AUTHOR]

A P102L point mutation in the prion protein gene ( PRNP) usually causes Gerstmann–Sträussler–Scheinker disease (GSS), which is a rare hereditary transmissible spongiform encephalopathy (TSE). The clinical features include ataxia in 50s age group with subsequent dementia, spastic paraparesis and extrapyramidal signs. Many families have been reported from the Caucasian population, but only one from the Chinese. We hereby report a large Chinese family with P102L mutation of PRNP whose clinical manifestations at onset were intriguingly heterogeneous, either rapidly progressive dementia with scanty other neurological features or slowly progressive ataxia followed by cognitive impairment. The four-generation pedigree included eight patients with a mean age at onset of 36.9 ± 12.9 (mean ± SD) years. Mean disease duration to death in the four patients was 5.5 ± 1.7 (mean ± SD) years. Molecular analysis revealed a P102L mutation and M129 polymorphism in the PRNP gene in all affected individuals. TSE with P102L mutation of PRNP appears to have a remarkably variable phenotypic expressivity that may change with time and does not appear related to the codon 129 polymorphism. [ABSTRACT FROM AUTHOR]

Voltage-gated K+ channels exist in vivo as multiprotein complexes made up of pore-forming and ancillary subunits. To further our understanding of the role of a dipeptidyl peptidase-related ancillary subunit, DPP10, we expressed it with Kv4.3 and Kv1.4, two channels responsible for fast-inactivating K+ currents. Previously, DPP10 has been shown to effect Kv4 channels. However, Kv1.4, when expressed with DPP10, showed many of the same effects as Kv4.3, such as faster time to peak current and negative shifts in the half-inactivation potential of steady-state activation and inactivation. The exception was recovery from inactivation, which is slowed by DPP10. DPP10 expressed with Kv4.3 caused negative shifts in both steady-state activation and inactivation of Kv4.3, but no significant shifts were detected when DPP10 was expressed with Kv4.3 + KChIP2b (Kv channel interacting protein). DPP10 and KChIP2b had different effects on closed-state inactivation. At -60 mV, KChIP2b nearly abolishes closed-state inactivation in Kv4.3, whereas it developed to a much greater extent in the presence of DPP10. Finally, expression of a DPP10 mutant consisting of its transmembrane and cytoplasmic 58 amino acids resulted in effects on Kv4.3 gating that were nearly identical to those of wild-type DPP10. These data show that DPP10 and KChIP2b both modulate Kv4.3 inactivation but that their primary effects are on different inactivation states. Thus DPP10 may be a general modulator of voltage-gated K+ channel inactivation; understanding its mechanism of action may lead to deeper understanding of the inactivation of a broad range of K+ channels. [ABSTRACT FROM AUTHOR]

Identification of genetic mutations has been of burgeoning importance in amyotrophic lateral sclerosis (ALS) in recent years. The aim of this study was to determine the frequency and spectrum of mutations in major ALS-causing genes in a Taiwanese ALS cohort of Han Chinese origin. Mutational analyses of the SOD1 , TARDBP , FUS , OPTN , VCP , UBQLN2 , SQSTM1 , PFN1 , HNRNPA1 , and HNRNPA2B1 genes were carried out by direct sequencing in 161 unrelated patients with ALS, including 30 with familial ALS (FALS) and 131 with sporadic ALS (SALS). The CAG repeat size in ATXN2 and the GGGGCC repeat expansion in C9ORF72 of the patients were also investigated. Mutations were identified in 33 patients (20.5%, 33/161), including 22 with FALS and 11 with SALS. Mutations were identified most frequently in SOD1 (7.5%). Three mutations are novel, including SOD1 p.G10A, SOD1 p.D83N, and OPTN p.L494W. These findings broaden the spectrum of ALS-causing mutations and are indispensable for designing optimal strategies of mutational analysis and genetic counseling of ALS for patients of Chinese origin. [ABSTRACT FROM AUTHOR]

Two dimension (2D) layered molybdenum disulfide (MoS2) has emerged as a promising candidate for the anode material in lithium ion batteries (LIBs). Herein, 2D MoSx (2⩽x⩽3) nanosheet-coated 1D multiwall carbon nanotubes (MWNTs) nanocomposites with hierarchical architecture were synthesized via a high-throughput solvent thermal method under low temperature at 200°C. The unique hierarchical nanostructures with MWNTs backbone and nanosheets of MoSx have significantly promoted the electrode performance in LIBs. Every single MoSx nanosheet interconnect to MWNTs centers with maximized exposed electrochemical active sites, which significantly enhance ion diffusion efficiency and accommodate volume expansion during the electrochemical reaction. A remarkably high specific capacity (i.e., > 1000 mAh/g) was achieved at the current density of 50 mA g-1, which is much higher than theoretical numbers for either MWNTs or MoS2 along (∼372 and ∼670 mAh/g, respectively). We anticipate 2D nanosheets/1D MWNTs nanocomposites will be promising materials in new generation practical LIBs [ABSTRACT FROM AUTHOR]