Improvement of the Cathode Electrolyte Interphase on P2-Na_2/3Ni_1/3Mn_2/3O₂ by Atomic Layer Deposition

Atomic layer deposition (ALD) is a commonly used coating technique for lithium ion battery electrodes. Recently, it has been applied to sodium ion battery anode materials. ALD is known to improve the cycling performance, Coulombic efficiency of batteries, and maintain electrode integrity. Here, the electrochemical performance of uncoated P2-Na_2/3Ni_1/3Mn_2/3O₂ electrodes is compared to that of ALD-coated Al₂O₃ P2-Na_2/3Ni_1/3Mn_2/3O₂ electrodes. Given that ALD coatings are in the early stage of development for NIB cathode materials, little is known about how ALD coatings, in particular aluminum oxide (Al₂O₃), affect the electrode–electrolyte interface. Therefore, full characterizations of its effects are presented in this work. For the first time, X-ray photoelectron spectroscopy (XPS) is used to elucidate the cathode electrolyte interphase (CEI) on ALD-coated electrodes. It contains less carbonate species and more inorganic species, which allows for fast Na kinetics, resulting in significant increase in Coulombic efficiency and decrease in cathode impedance. The effectiveness of Al₂O₃ ALD coating is also surprisingly reflected in the enhanced mechanical stability of the particle which prevents particle exfoliation

The morphology of the STEC-specific phages isolated from Salinas area.

<p>(A) O157-specific bacteriophage, (B) O145-specific bacteriophage, (C) O45-specific bacteriophage, (D) O179-specific bacteriophage.</p

Shiga toxin-producing <i>E</i>. <i>coli</i> (STEC) strains isolated from different sources by U.S. Department of Agriculture ARS used for free STEC-specific phage isolation.

<p>Shiga toxin-producing <i>E</i>. <i>coli</i> (STEC) strains isolated from different sources by U.S. Department of Agriculture ARS used for free STEC-specific phage isolation.</p

Geographical location of the watershed sites where the samples were collected in the area of Salinas Valley.

<p>Sample sites are labeled with a six-letter acronym in black type (locations with agriculture impact) or red type (locations with human impact). Insert is an expanded view of the area near the city of Salinas.</p

Summary of phage and STEC isolation data from water samples collected from Salinas, CA.

<p>The acronym is used for each sample site with the number of water samples collected. Red oval shape with red letter indicates isolation of STEC-specific phage, and green rectangular shape with green letters indicates STEC bacterial isolation.</p

Effect of the environmental factors, rain precipitation and solar radiation, on the isolation of free STEC-specific phages from the overall sample sites.

<p>Effect of the environmental factors, rain precipitation and solar radiation, on the isolation of free STEC-specific phages from the overall sample sites.</p

Samples with positive of STEC-specific phages and STEC strains throughout sampling period displayed by sample month.

<p>Samples with positive of STEC-specific phages and STEC strains throughout sampling period displayed by sample month.</p

Development of a Robust Method for Isolation of Shiga Toxin-Positive <i>Escherichia coli</i> (STEC) from Fecal, Plant, Soil and Water Samples from a Leafy Greens Production Region in California

<div><p>During a 2.5-year survey of 33 farms and ranches in a major leafy greens production region in California, 13,650 produce, soil, livestock, wildlife, and water samples were tested for Shiga toxin (<i>stx</i>)-producing <i>Escherichia coli</i> (STEC). Overall, 357 and 1,912 samples were positive for <i>E. coli</i> O157:H7 (2.6%) or non-O157 STEC (14.0%), respectively. Isolates differentiated by O-typing ELISA and multilocus variable number tandem repeat analysis (MLVA) resulted in 697 O157:H7 and 3,256 non-O157 STEC isolates saved for further analysis. Cattle (7.1%), feral swine (4.7%), sediment (4.4%), and water (3.3%) samples were positive for <i>E. coli</i> O157:H7; 7/32 birds, 2/145 coyotes, 3/88 samples from elk also were positive. Non-O157 STEC were at approximately 5-fold higher incidence compared to O157 STEC: cattle (37.9%), feral swine (21.4%), birds (2.4%), small mammals (3.5%), deer or elk (8.3%), water (14.0%), sediment (12.3%), produce (0.3%) and soil adjacent to produce (0.6%). <i>stx1</i>, <i>stx2</i> and <i>stx1/stx2</i> genes were detected in 63%, 74% and 35% of STEC isolates, respectively. Subtilase, intimin and hemolysin genes were present in 28%, 25% and 79% of non-O157 STEC, respectively; 23% were of the “Top 6″ O-types. The initial method was modified twice during the study revealing evidence of culture bias based on differences in virulence and O-antigen profiles. MLVA typing revealed a diverse collection of O157 and non-O157 STEC strains isolated from multiple locations and sources and O157 STEC strains matching outbreak strains. These results emphasize the importance of multiple approaches for isolation of non-O157 STEC, that livestock and wildlife are common sources of potentially virulent STEC, and evidence of STEC persistence and movement in a leafy greens production environment.</p></div

RT-PCR with and without Environmental Master Mix (EMM) to detect <i>stx</i> genes in environmental sample enrichments spiked with STEC.

a<p>Lettuce = Iceberg; Water = surface water; Feces = cattle feces. Plants and soil were collected from coded farm location F; Cattle feces were collected from coded ranch location Q. Surface water was collected locally (37.882855 N, 122.300007 W). All samples tested as STEC-negative prior to spiking.</p>b<p>Enrichments were spiked with 10 fold dilutions of <i>E. coli</i> O157 strain RM1484 (0–20×10⁶ CFU/mL) and subjected to RT-PCR using AmpliTaq Gold or EMM (see Methods). Each of the samples produced a Ct, except for several soil and feces samples lacking a Ct even at the highest inoculum. A Ct of 27 corresponds to the upper limit we have set for culturing enrichment samples for isolation of STEC. SD, standard deviation. Different letter superscripts designate samples with a significant difference in treatment results (P<0.05).</p

Sensitivity of three enrichment methods for recovery of <i>E. coli</i> O157 from environmental samples.

a<p>2 hr incubation at 25<b>°</b>C and <u>8 hr</u> at 42<b>°</b>C with shaking.</p>b<p>Inoculum was <i>E. coli</i> O157 RM1484. Inoculum level was determined by serial plating on LB. <100% of samples positive are shown in <b>boldface</b> type.</p>c<p>2 hr incubation at 25<b>°</b>C and <u>20 hr</u> at 42<b>°</b>C with shaking.</p