The surface coating of cathodes using insulator films has proven to be a promising method for high-voltage 10 cathode stabilization in Li-ion batteries, but there is still substantial uncertainty about how these films function. More 11 specifically, there is limited knowledge of lithium solubility and transport through the films, which is important for coating 12 design and development. This study uses first-principles calculations based on Density Functional Theory to examine the 13 diffusivity of interstitial lithium in the crystals of α-AlF3, α-Al2O3, m-ZrO2, c-MgO, and α-quartz SiO2, which provide benchmark 14 cases for further understanding of insulator coatings in general. In addition, we propose an Ohmic electrolyte model to predict 15 resistivities and overpotential contributions under battery operating conditions. For the crystalline materials considered we 16 predict that Li + diffuses quite slowly, with a migration barrier larger than 0.9 eV in all crystalline materials except α-quartz SiO2, 17 which is predicted to have a migration barrier of 0.276 eV along <001>. These results suggest that the stable crystalline forms of 18 these insulator materials, except for oriented α-quartz SiO2, are not practical for conformal cathode coatings. Amorphous Al2O3 19 and AlF3 have higher Li + diffusivities than their crystalline counterparts. Our predicted amorphous Al2O3 resistivity (1789 MΩm) is 20 close to the top of the range of the fitted resistivities extracted from previous experiments on nominal Al2O3 coatings (7.8 to 913 21 MΩm) while our predicted amorphous AlF3 resistivity (114 MΩm) is very close to the middle of the range. These comparisons 22 support our framework for modeling and understanding the impact on overpotential of conformal coatings in terms of their 23 fundamental thermodynamic and kinetic properties, and support that these materials can provide practical conformal coatings 24 in their amorphous form.25 I. Introduction 26 27 Surface modification of the cathode by artificial coating is an effective strategy to stabilize Li-ion batteries (LIBs) 28 operating at high voltages.[1-10] Nevertheless, the coating functionalities and the stabilizing mechanisms are still not 29 fully understood and currently a subject of intensive research in the development of next-generation LIBs. Several 30 roles for the coating have been proposed to account for its positive impacts on the cathode performance, including: (i) 31 electrical conduction medium that facilitates electron transport between cathode active particles,[11] (ii) modifier of 32 cathode surface chemistry that changes chemical properties of the cathode surface to improve stability and 33 performance,[12] (iii) HF scavenger that locally reduces the acidity of the electrolyte near the cathode surface, thereby 34 reducing electrolyte degradation,[13-15] and (iv) physical protection barrier that suppresses electrolyte oxidation and 35 cathode corrosion. [8,[16][17][18][19][20] In general, role (iii) and, particularly, role (iv) are the most widely cl...

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ObjectivesTo determine prospectively the causative pathogens of central nervous system (CNS) infections in patients admitted to a tertiary referral hospital in Hanoi, Vietnam.MethodsFrom May 2007 to December 2008, cerebrospinal fluid (CSF) samples from 352 adults with suspected meningitis or encephalitis underwent routine testing, staining (Gram, Ziehl-Nielsen, India ink), bacterial culture and polymerase chain reaction targeting Neisseria meningitidis, Streptococcus pneumoniae, S. suis, Haemophilus influenzae type b, Herpes simplex virus (HSV), Varicella Zoster virus (VZV), enterovirus, and 16S ribosomal RNA. Blood cultures and clinically indicated radiology were also performed. Patients were classified as having confirmed or suspected bacterial (BM), tuberculous (TBM), cryptococcal (CRM), eosinophilic (EOM) meningitis, aseptic encephalitis/meningitis (AEM), neurocysticercosis and others.Results352 (male: 66%) patients were recruited: median age 34 years (range 13–85). 95/352 (27.3%) diagnoses were laboratory confirmed and one by cranial radiology: BM (n = 62), TBM (n = 9), AEM (n = 19), CRM (n = 5), and neurocysticercosis (n = 1, cranial radiology). S. suis predominated as the cause of BM [48/62 (77.4%)]; Listeria monocytogenese (n = 1), S. pasteurianus (n = 1) and N. meningitidis (n = 2) were infrequent. AEM viruses were: HSV (n = 12), VZV (n = 5) and enterovirus (n = 2). 5 patients had EOM. Of 262/352 (74.4%) patients with full clinical data, 209 (79.8%) were hospital referrals and 186 (71%) had been on antimicrobials. 21 (8%) patients died: TBM (15.2%), AEM (10%), and BM (2.8%).ConclusionsMost infections lacked microbiological confirmation. S. suis was the most common cause of BM in this setting. Improved diagnostics are needed for meningoencephalitic syndromes to inform treatment and prevention strategies.