RESUMEN
Rapid rise in temperature in summer causes severe injury to cool-season turfgrass of both native species and introduced ones in Heilongjiang of Northeast China. The objectives of this study were to compare physiological responses to seasonal heat stresses and turf performances between native and introduced commercial Poa accessions. Three Chinese native Poa species (i.e., P. pratensis, P. sibirica and P. sphondylodes) and three USA Kentucky bluegrass cultivars (ie. 'Midnight', 'Moonlight' and 'BlueChip') were evaluated under field conditions in 2017 and 2018. All accessions showed unique characteristics and considerable seasonal differences in response to temperatures. However, performances over all accessions were largely similar in early spring and autumn. In summer, native P. pratensis performed similar to 'Midnight', 'Moonlight' or 'BlueChip', with respect to such traits or parameters as quality, coverage, color intensity, growth rate, osmolytes, ROS and anti-oxidant production. Native P. pratensis could be used as a new turf resource for further improvement and application under the specific climatic conditions in Heilongjiang; native P. sphondylodes may be used in repairing damaged environments or for alternative seasonal greenness.
RESUMEN
Solid-state lithium-metal batteries with solid electrolytes are promising for next-generation energy-storage devices. However, it remains challenging to develop solid electrolytes that are both mechanically robust and strong against external mechanical load, due to the brittleness of ceramic electrolytes and the softness of polymer electrolytes. Herein, a nacre-inspired design of ceramic/polymer solid composite electrolytes with a "brick-and-mortar" microstructure is proposed. The nacre-like ceramic/polymer electrolyte (NCPE) simultaneously possesses a much higher fracture strain (1.1%) than pure ceramic electrolytes (0.13%) and a much larger ultimate flexural modulus (7.8 GPa) than pure polymer electrolytes (20 MPa). The electrochemical performance of NCPE is also much better than pure ceramic or polymer electrolytes, especially under mechanical load. A 5 × 5 cm2 pouch cell with LAGP/poly(ether-acrylate) NCPE exhibits stable cycling with a capacity retention of 95.6% over 100 cycles at room temperature, even undergoes a large point load of 10 N. In contrast, cells based on pure ceramic and pure polymer electrolyte show poor cycle life. The NCPE provides a new design for solid composite electrolyte and opens up new possibilities for future solid-state lithium-metal batteries and structural energy storage.
RESUMEN
Safety is critical to developing next-generation batteries with high-energy density. Polyether-based electrolytes, such as poly(ethylene oxide) and poly(ethylene glycol) (PEG), are attractive alternatives to the current flammable liquid organic electrolyte, since they are much more thermally stable and compatible with high-capacity lithium anode. Unfortunately, they are not stable with 4 V Li(NixMnyCo1-x-y)O2 (NMC) cathodes, hindering them from application in batteries with high-energy density. Here, we report that the compatibility between PEG electrolyte and NMC cathodes can be significantly improved by forming a 2 nm Al2O3 coating on the NMC surface. This nanoscale coating dramatically changes the composition of the cathode electrolyte interphase and thus stabilizes the PEG electrolyte with the NMC cathode. With Al2O3, the capacity remains at 84.7% after 80 cycles and 70.3% after 180 cycles. In contrast, the capacity fades to less than 50% after only 20 cycles in bare NMC electrodes. This study opens a new opportunity to develop safe electrolyte for lithium batteries with high-energy density.
RESUMEN
A novel double-layered antibacterial coating was fabricated on pure titanium (Ti) via a simple three-step electrodeposition process. Scanning electronic microscopy (SEM) images show that the coating was constructed with the inner layer of TiO2 nanotubes doped with silver nanoparticles (TNTs/Ag) and the outer layer of chitosan-gelatin mixture with zinc oxide and silver nanoparticles (CS-Gel-Ag-ZnO). In comparison, we also investigated the composition, structure and antibacterial properties of pure Ti coated with TNTs, TNTs/Ag or TNTs/Ag + CS-Gel-Ag-ZnO, respectively. The TNTs was about 100 nm wide and 240 nm to 370 nm tall, and most Ag nanoparticles (Ag NPs) with diameter smaller than 20 nm were successfully deposited inside the tubes. The CS-Gel-Ag-ZnO layer was continuous and uniform. Antibacterial activity against planktonic and adherent bacteria were both investigated. Agar diffusion test against Staphylococcus aureus (S. aureus) shows improved antibacterial capacity of the TNTs/Ag + CS-Gel-Ag-ZnO coating, with a clear zone of inhibition (ZOI) up to 14.5 mm wide. Dead adherent bacteria were found on the surface by SEM. The antibacterial rate against planktonic S. aureus was as high as 99.2% over the 24 h incubation period.
