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The effects of surface treatment combining corona discharge and hydrogen peroxide (H2O2) on the electrochemical performance of carbon felt electrodes for vanadium redox flow batteries (VRFBs) have been thoroughly investigated. A high concentration of oxygen functional groups has been successfully introduced onto the surface of the carbon felt electrodes by a specially designed surface treatment, which is mainly responsible for improving the energy efficiency of VRFBs. In addition, the wettability of the carbon felt electrodes also can be significantly improved. The energy efficiency of the VRFB cell employing the surface modified carbon felt electrodes is improved by 7% at high current density (148 mA cm−2). Such improvement is attributed to the faster charge transfer and better wettability allowed by surface-active oxygen functional groups. Moreover, this method is much more competitive than other surface treatments in terms of processing time, production costs, and electrochemical performance.

Mesoporous hollow fibres of MnCo2O4 and CoMn2O4 were synthesized by electrospinning and highly exothermic oxygen-mediated combustion reactions during calcination, in which the heating rate affected the final fibre morphology (e.g., single- or double-shell). The anodes consisting of hollow fibres showed excellent electrochemical properties for lithium-ion batteries.

The morphology and electronic structure of metal oxides, including TiO(2) on the nanoscale, definitely determine their electronic or electrochemical properties, especially those relevant to application in energy devices. For this purpose, a concept for controlling the morphology and electrical conductivity in TiO(2), based on tuning by electrospinning, is proposed. We found that the 1D TiO(2) nanofibers surprisingly gave higher cyclic retention than 0D nanopowder, and nitrogen doping in the form of TiO(2)N(x) also caused further improvement. This is due to higher conductivity and faster Li(+) diffusion, as confirmed by electrochemical impedance spectra. Our findings provide an effective and scalable solution for energy storage efficiency.

Rechargeable metal-air batteries are considered a promising energy storage solution owing to their high theoretical energy density. The major obstacles to realising this technology include the slow kinetics of oxygen reduction and evolution on the cathode (air electrode) upon battery discharging and charging, respectively. Here, we report non-precious metal oxide catalysts based on spinel-type manganese-cobalt oxide nanofibres fabricated by an electrospinning technique. The spinel oxide nanofibres exhibit high catalytic activity towards both oxygen reduction and evolution in an alkaline electrolyte. When incorporated as cathode catalysts in Zn-air batteries, the fibrous spinel oxides considerably reduce the discharge-charge voltage gaps (improve the round-trip efficiency) in comparison to the catalyst-free cathode. Moreover, the nanofibre catalysts remain stable over the course of repeated discharge-charge cycling; however, carbon corrosion in the catalyst/carbon composite cathode degrades the cycling performance of the batteries.

One-dimensional nanomaterials have short Li(+) diffusion paths and promising structural stability, which results in a long cycle life during Li(+) insertion and extraction processes in lithium rechargeable batteries. In this study, we fabricated one-dimensional spinel Li4Ti5O12 (LTO) nanofibers using an electrospinning technique and studied the Zr(4+) doping effect on the lattice, electronic structure, and resultant electrochemical properties of Li-ion batteries (LIBs). Accommodating a small fraction of Zr(4+) ions in the Ti(4+) sites of the LTO structure gave rise to enhanced LIB performance, which was due to structural distortion through an increase in the average lattice constant and thereby enlarged Li(+) diffusion paths rather than changes to the electronic structure. Insulating ZrO2 nanoparticles present between the LTO grains due to the low Zr(4+) solubility had a negative effect on the Li(+) extraction capacity, however. These results could provide key design elements for LTO anodes based on atomic level insights that can pave the way to an optimal protocol to achieve particular functionalities.

OBJECTIVE-Protein kinase C (PKC)-␦, an upstream regulator of the Akt survival pathway, contributes to cellular dysfunction in the pathogenesis of diabetes. Herein, we examined the role of PKC-␦ in neuronal apoptosis through Akt in the retinas of diabetic rats.RESEARCH DESIGN AND METHODS-We used retinas from 24-and 35-week-old male Otsuka Long-Evans Tokushima fatty (OLETF) diabetic and Long-Evans Tokushima Otsuka (LETO) nondiabetic rats. To assess whether PKC-␦ affects Akt signaling and cell death in OLETF rat retinas, we examined 1) PKC-␦ activity and apoptosis; 2) protein levels of phosphatidylinositol 3-kinase (PI 3-kinase) p85, heat shock protein 90 (HSP90), and protein phosphatase 2A (PP2A); 3) Akt phosphorylation; and 4) Akt binding to HSP90 or PP2A in LETO and OLETF retinas in the presence or absence of rottlerin, a highly specific PKC-␦ inhibitor, or small interfering RNAs (siRNAs) for PKC-␦ and HSP90.RESULTS-In OLETF retinas from 35-week-old rats, ganglion cell death, PKC-␦ and PP2A activity, and Akt-PP2A binding were significantly increased and Akt phosphorylation and Akt-HSP90 binding were decreased compared with retinas from 24-week-old OLETF and LETO rats. Rottlerin and PKC-␦ siRNA abrogated these effects in OLETF retinas from 35-week-old rats. HSP90 siRNA significantly increased ganglion cell death and Akt-PP2A complexes and markedly decreased HSP90-Akt binding and Akt phosphorylation in LETO retinas from 35-week-old rats compared with those from nontreated LETO rats.CONCLUSIONS-PKC-␦ activation contributes to neuro-retinal apoptosis in diabetic rats by inhibiting Akt-mediated signaling pathways. Diabetes 57:2181-2190, 2008 P rotein kinase C (PKC)-␦, a ubiquitously expressed isoform of the novel PKC subfamily, mediates an anti-apoptotic signaling cascade through the phosphatidylinositol 3-kinase (PI 3-kinase)-mediated survival pathway (1,2) and also promotes apoptosis by interfering with Akt signaling (3-5).Akt is a downstream target of PI 3-kinase that plays an integral role in cell survival. Dysregulation of Akt is frequently observed in diseases such as cancers and diabetes (6 -8). PI 3-kinase activates Akt through the phosphorylation of two key regulatory residues, Thr308 and Ser473, on Akt. Phosphorylation of both residues is necessary for full activation of Akt and subsequent regulation of many PI 3-kinase-mediated biological responses (9,10).Protein phosphatase 2A (PP2A), a major cellular serine/ threonine phosphatase, regulates the phosphorylation state of cellular proteins in various pathological conditions (11-13). Recently, it has been reported that PP2A is involved in the regulation of cell proliferation and survival through its ability to dephosphorylate Akt (11-15). Furthermore, heat shock protein 90 (HSP90) counteracts the effect of PP2A in cells through direct binding to Akt, protecting Akt from PP2A-mediated dephosphorylation and thus functioning as a positive regulator of Akt signaling (13,15,16). Of note, numerous reports have suggested that Akt-or HSP-mediated cytoprotection is r...

New insight into the oxidation mechanism of solid Li 2 S is presented by investigating a specially designed cell in which the Li 2 S particles are electrically isolated from the carbon cathode. Surprisingly, the cell containing the isolated Li 2 S particles delivered considerable charge and discharge capacities despite the prevention of any charge transfer process between the Li 2 S particles and the carbon cathode. This fact directly indicates that the electrochemical oxidation of Li 2 S occurs not through a direct charge (electron) transfer between solid Li 2 S and conducting materials but through chemical reactions coupled with the charge transfer process. We believe that these unexpected results will greatly contribute to a deep understanding of the exact working mechanism of Li-S batteries and Li 2 S cathodes as well as a paradigm shift toward an innovative and rational design of Li-S batteries.