This study reports the preparation of Al2O3 and TiO2 coatings on the as-prepared LiCoO2 electrodes using atomic layer deposition (ALD). A thin Al2O3 ALD coating was shown to eliminate capacity
fading
effectively during repeated charging and discharging, whereas a TiO2 coating led to significant improvement only at high cycle
numbers. An analysis of the differential capacity versus potential
curves suggests that this poorer cycling performance could be related
to the participation of the TiO2 thin film in the redox
reaction. Graphical representation of the energy levels of the various
ALD coatings on LiCoO2 during charging and discharging
indicated that the redox current is impeded at the Al2O3–LiCoO2 junction, whereas electrons and
holes were energetic enough to flow into the TiO2 because
of the smaller band gap energy. The barrier between the valence band
maxima of TiO2 and LiCoO2 expands as the charge–discharge
cycle number increases, eventually making TiO2 redox-inactive.
These conclusions are supported by both XPS spectra and the cycle
performance in the established literature references. Our results
suggest that large band gap materials should be considered to be potentially
useful ALD coatings on cathode materials.
CuOx nanowires were synthesized by a low-cost and large-scale electrochemical process with AAO membranes at room temperature and its resistive switching has been demonstrated. The switching characteristic exhibits forming-free and low electric-field switching operation due to coexistence of significant amount of defects and Cu nanocrystals in the partially oxidized nanowires. The detailed resistive switching characteristics of CuOx nanowire systems have been investigated and possible switching mechanisms are systematically proposed based on the microstructural and chemical analysis via transmission electron microscopy.
A technique of layer-by-layer (LbL) self-assembly was used to prepare transparent multilayered gas barrier films consisting of graphene oxide (GO)/branched poly(ethylenimine) (BPEI) on a poly(ethylene terephthalate) substrate. The effect of the GO suspension pH on the nanostructure and oxygen barrier properties of the GO/BPEI film was investigated. The oxygen barrier properties of the assemblies were shown to be highly dependent on the pH. It was demonstrated that the film assemblies prepared using a GO suspension with a pH of 3.5 exhibited very dense and ordered structures and delivered very low oxygen transmission rates (the lowest was <0.05 cm(3) m(-2) day(-1)). The assemblies were characterized with ultraviolet-visible spectroscopy and ellipsometry to identify the film growth mechanism, and the result indicated a linear growth behavior. To analyze the nanostructure of the films, atomic force microscopy, transmission electronic microscopy, and grazing incidence wide-angle X-ray diffraction were used.
Pulmonary fibrosis (PF) is a major public health problem with limited therapeutic options. There is a clear need to identify novel mediators of PF to develop effective therapeutics. Here we show that an ER protein disulfide isomerase, thioredoxin domain containing 5 (TXNDC5), is highly upregulated in the lung tissues from both patients with idiopathic pulmonary fibrosis and a mouse model of bleomycin (BLM)-induced PF. Global deletion of Txndc5 markedly reduces the extent of PF and preserves lung function in mice following BLM treatment. Mechanistic investigations demonstrate that TXNDC5 promotes fibrogenesis by enhancing TGFβ1 signaling through direct binding with and stabilization of TGFBR1 in lung fibroblasts. Moreover, TGFβ1 stimulation is shown to upregulate TXNDC5 via ER stress/ATF6-dependent transcriptional control in lung fibroblasts. Inducing fibroblast-specific deletion of Txndc5 mitigates the progression of BLM-induced PF and lung function deterioration. Targeting TXNDC5, therefore, could be a novel therapeutic approach against PF.
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