Despite the theoretically high energy density, the practical energy density of Li-S batteries at the moment does not meet the demand due to low sulfur (S) loading (<2 mg cm −2 ), large electrolyte amount (electrolyte/sulfur ratio >20 µL mg −1 ), and excess lithium (Li) metal use (>10 times excess). [5] In particular, large electrolyte usage (flooding) greatly diminishes the practical energy density of Li-S batteries. Due to the intrinsic solution-based redox chemistry, however, many of the challenges arise from minimizing the electrolyte/ sulfur ratio (E/S ratio). Since soluble lithium polysulfide (LiPS, Li 2 S x when 2 < x ≤ 8) intermediates are self-redox mediating, the decrease in the LiPS dissolution causes a sluggish sulfur conversion and high polarization. [6] Next, the morphology of lithium sulfide (Li 2 S) electrodeposition and the kinetics of the re-oxidation are affected by the sulfur species solubility as well. [7] Hence, uncontrolled precipitation and continual accumulation of Li 2 S limit the discharge capacity and further passivate the cathode interface throughout the cycling. [8] Reducing the electrolyte volume exacerbates not only the cathode performance but also the anode stability. A high reactivity and an infinite volume change of the Li metal anode cause the incessant decomposition of the electrolyte. Therefore, the lean electrolyte condition accelerates the increase of the cell resistance and provokes earlier performance failure compared to the flooding electrolyte system. [9] Manipulating electrolyte materials (solvents, salt anions, and additives) has a considerable impact on the electrochemical performance of Li-S batteries. There have been studies in which solvents with high Gutmann donor numbers (DNs) form strong interactions with lithium ions (Li + ) and promote the solvation of polysulfide (PS) anions. The increased LiPS solubility facilitates the solution-mediated reaction pathway, enabling fast reaction kinetics and high sulfur utilization. [10] Furthermore, the same merits can also be achieved with salt anions having high-DNs [11] or additives promoting ionic solvation. [12] Under a lean electrolyte regime, the role of highly solvating electrolytes becomes more prominent because of the limited solubility of sulfur species. For example, high-DN solvents can enhance the sulfur utilization under the reduced electrolyte amount by promoting the charge/discharge reactions. [13] Despite this fact, the Minimizing electrolyte use is essential to achieve high practical energy density of lithium-sulfur (Li-S) batteries. However, the sulfur cathode is more readily passivated under a lean electrolyte condition, resulting in low sulfur utilization. In addition, continuous electrolyte decomposition on the Li metal anode aggravates the problem, provoking rapid capacity decay. In this work, the dual functionalities of NO 3 − as a high-donor-number (DN) salt anion is presented, which improves the sulfur utilization and cycling stability of lean-electrolyte Li-S batteries. The NO 3 − anion eleva...
Highly reversible aqueous zinc anodes are demonstrated via suppressing surface diffusion of Zn adatoms from strong orbital hybridization of the Zn adatoms and single vacancy defects.
Bacterial biofilms are responsible for a wide range of persistent infections. In the clinic, diagnosis of biofilm-associated infections relies heavily on culturing methods, which fail to detect nonculturable bacteria. Identification of novel fluorescent probes for biofilm imaging will greatly facilitate diagnosis of pathogenic bacterial infection. Herein, we report a novel fluorescent probe, CDy11 (compound of designation yellow 11), which targets amyloid in the Pseudomonas aeruginosa biofilm matrix through a diversity oriented fluorescent library approach (DOFLA). CDy11 was further demonstrated for in vivo imaging of P. aeruginosa in implant and corneal infection mice models.
The rapid and sensitive classification of bacteria is the first step of bacterial community researchand the treatment of infection. Herein, afluorescent probe BacGO is presented, which shows the best universal selectivity for Gram-positive bacteria among knownp robes with am inimum staining procedure for sample detection and enrichment of the live bacteria. BacGO could also be used to assess of the Gram status in the bacterial community from wastewater sludge. Furthermore, BacGO could sensitively and selectively detect aG ram-positive bacterial infection, not only in vitro but also using an in vivo keratitis mouse model. BacGO provides an unprecedented researchtool for the study of dynamic bacterial communities and for clinical application.
The application of nonthermal atmospheric pressure plasma to intracoronal bleaching could be a novel and efficient therapy in the bleaching of haemorrhagically stained teeth.
Energy-efficient
solution-processed organic field-effect transistors
(OFETs) are highly sought after in the low-cost printing industry
as well as for the manufacture of flexible and other next-generation
devices. The fabrication of such electronic devices requires high-functioning
insulating materials that are chemically and mechanically robust to
avoid lowering insulating properties during the device fabrication
process or utilization of devices. In this study, we report a facile,
fluorinated, UV-assisted cross-linker series using a fluorophenyl
azide (FPA), which reacts with the C–H groups of a conventional
polymer. This demonstrates the application of the cross-linked films
in OFET gate dielectrics. The effects of the cross-linkable chemical
structure of the FPA series on the cross-linking chemistry, photopatternability,
and dielectric properties of the resulting films are investigated
for low/high-k or amorphous/crystalline polymeric
gate dielectric materials. The characteristics of insulating layers
and behavior of OFETs containing these cross-linked gate dielectrics
(for example, leakage current density (J), hysteresis,
and charge trap density) depend on the polymer type. Furthermore,
an organic-based complementary inverter and various printable OFETs
with excellent electrical characteristics are successfully fabricated.
Thus, these reported cross-linkers that enable the solution process
and patterning of well-developed conventional polymer dielectric materials
are promising for the realization of a more sustainable next-generation
industrial technology for flexible and printable devices.
The electron heating mode transition induced by ultra-high frequency in atmospheric-pressure microplasmas was investigated using particle-in-cell simulation with a Monte Carlo collision. Interestingly, this discharge mode transition is accompanied by non-monotonic evolution of electron kinetics such as effective electron temperature, plasma density, and electron energy on the electrode. In this study, the highest flux of energetic electrons (ɛ > 4 eV) usable for tailoring the surface chemistry in atmospheric microplasmas is obtained at the specific frequency (400 MHz), where an optimal trade-off is established between the amplitude of sheath oscillations and the power coupled to electrons for sub-millimeter dimensions (200 µm).
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