Deciphering Enhanced Solid-State Kinetics of Li–S Batteries via Te Doping

Owing to their high gravimetric energy, low cost, and wide availability of required materials, Li–S batteries (LSBs) are considered as a promising next-generation energy storage technology. However, the sluggish redox kinetics and dissolution of lithium polysulfides during the electrochemical reactions are key problems to overcome. The improvement of the long-term cycle life of LSBs solely by converting insoluble solid-state electrolyte-soluble lithium polysulfides (LiPSs) (Li2Sx, where 1 ≤ x ≤ 2, 836 mAh g–1) is an ingenious method, but solid-state LiPS conversion has sluggish redox kinetics owing to the intrinsically low electrical conductivity of solid-state LiPS compounds (Li2S and Li2S2). This study applied Te doping to S cathodes and conducted experimental and theoretical analyses on the Te-doped solid-state LiPSs to investigate the effect of Te on the redox kinetics of the solid-state LiPS conversions for high-performance LSBs. The qualitative and quantitative electrochemical characterization demonstrated that Te induced an increase in the kinetics. Furthermore, the enhanced kinetics were explained at the atomic scale by the theoretical thermodynamics and chemomechanics investigations. The design of high-performance LSBs will benefit the strong understanding of Te-doped S electrodes in solid-state conversion

Severe persistent hypocholesterolemia after emergency gastrointestinal surgery predicts in-hospital mortality in critically ill patients with diffuse peritonitis

<div><p>Background</p><p>Plasma cholesterol acts as a negative acute phase reactant. Total cholesterol decreases after surgery and in various pathological conditions, including trauma, sepsis, burns, and liver dysfunction. This study aimed to determine whether hypocholesterolemia after emergency gastrointestinal (GI) surgery is associated with in-hospital mortality in patients with diffuse peritonitis.</p><p>Methods</p><p>The medical records of 926 critically ill patients who had undergone emergency GI surgery for diffuse peritonitis, between January 2007 and December 2015, were retrospectively analyzed. The integrated areas under the curve (iAUCs) were calculated to compare the predictive accuracy of total cholesterol values from postoperative days (PODs) 0, 1, 3, and 7. Cox proportional hazard regression modeling was performed for all possible predictors identified in the univariate and multivariable analyses.</p><p>Results</p><p>The total cholesterol level measured on POD 7 had the highest iAUC (0.7292; 95% confidence interval, 0.6696–0.7891) and was significantly better at predicting in-hospital mortality than measurements on other days. The optimal total cholesterol cut-off value for predicting in-hospital mortality was 61 mg/dL and was determined on POD 7. A Cox proportional hazard regression analysis revealed that a POD 7 total cholesterol level < 61 mg/dL was an independent predictor of in-hospital mortality after emergency GI surgery (hazard ratio, 3.961; 95% confidence interval, 1.786–8.784).</p><p>Conclusion</p><p>Severe persistent hypocholesterolemia (<61 mg/dL) on POD 7 independently predicted in-hospital mortality, after emergency GI surgery, in critically ill patients with diffuse peritonitis.</p></div

Baseline characteristics of the total population.^a

<p>Baseline characteristics of the total population.<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0200187#t001fn002" target="_blank">^a</a></p

Estimated iAUC differences using a bootstrapping method.

<p>Estimated iAUC differences using a bootstrapping method.</p

Univariate and multivariable Cox proportional hazards model for in-hospital mortality.

<p>Univariate and multivariable Cox proportional hazards model for in-hospital mortality.</p

Flow diagram of the patient selection process.

<p>Flow diagram of the patient selection process.</p

Comparison of the changes in total cholesterol levels between survivors and nonsurvivors.

<p>The time variations in total cholesterol levels were significantly different between survivors and nonsurvivors (Greenhouse-Geisser corrected, <i>P</i> < 0.001, using repeated-measures analysis of variance).</p

Time-dependent receiver operating curve analysis to evaluate the predictive accuracy of each measurement day.

<p>Results in the top right-hand corner of the figure indicate the integrated area under the curve (iAUC) and 95% confidence interval. The iAUC is a measure of the predictive accuracy for in-hospital mortality on each measurement day. The cholesterol level measured on postoperative day 7 had the highest iAUC.</p

Kaplan–Meier curve based on hypocholesterolemia severity (total cholesterol level ≥61 mg/dL versus total cholesterol level <61 mg/dL; log-rank test, <i>P</i> < 0.0001).

<p>Kaplan–Meier curve based on hypocholesterolemia severity (total cholesterol level ≥61 mg/dL versus total cholesterol level <61 mg/dL; log-rank test, <i>P</i> < 0.0001).</p