Although the rechargeable lithium–sulfur battery is an advanced energy storage system, its practical implementation has been impeded by many issues, in particular the shuttle effect causing rapid capacity fade and low Coulombic efficiency. Herein, we report a conductive porous vanadium nitride nanoribbon/graphene composite accommodating the catholyte as the cathode of a lithium–sulfur battery. The vanadium nitride/graphene composite provides strong anchoring for polysulfides and fast polysulfide conversion. The anchoring effect of vanadium nitride is confirmed by experimental and theoretical results. Owing to the high conductivity of vanadium nitride, the composite cathode exhibits lower polarization and faster redox reaction kinetics than a reduced graphene oxide cathode, showing good rate and cycling performances. The initial capacity reaches 1,471 mAh g−1 and the capacity after 100 cycles is 1,252 mAh g−1 at 0.2 C, a loss of only 15%, offering a potential for use in high energy lithium–sulfur batteries.

No abstract

Aim To evaluate the influence of diabetes on the severity and fatality of severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) infection. Materials and Methods The medical records of 66 hospitalized coronavirus disease 2019 (COVID‐19) patients were collected and classified into non‐severe (mild/moderate cases) and severe (severe/critical cases) groups. Logistic regression analysis was used to estimate the risk of severe COVID‐19 (severe/critical infection). In addition, a meta‐analysis including published studies reported the impact of diabetes on the severity and fatality of COVID‐19. The current study was conducted using fixed effects models. Results There were 22 diabetes and 44 non‐diabetes cases among the 66 hospitalized COVID‐19 patients. Seven patients with diabetes (31.82%) were diagnosed as severe COVID‐19 cases, which was significantly higher than that in the non‐diabetes group (4/44, 9.09%, P = .033). After adjustment for age and gender, diabetes was significantly associated with COVID‐19 severity (OR: 5.29, 95% CI: 1.07–26.02). A meta‐analysis further confirmed the positive association between diabetes and COVID‐19 severity (pooled OR = 2.58, 95% CI: 1.93–3.45). Moreover, the patients with diabetes infected with SARS‐CoV‐2 had a 2.95‐fold higher risk of fatality compared with those patients without diabetes (95% CI: 1.93–4.53). Conclusions Our findings provide new evidence that diabetes is associated with a higher risk of severity and fatality of COVID‐19. Therefore, intensive monitoring and antidiabetic therapy should be considered in patients with diabetes with SARS‐CoV‐2 infection.

Hypertension is a common comorbidity in COVID-19 patients. However, the association of hypertension with the severity and fatality of COVID-19 remain unclear. In the present meta-analysis, relevant studies reported the impacts of hypertension on SARS-CoV-2 infection were identified by searching PubMed, Elsevier Science Direct, Web of Science, Wiley Online Library, Embase and CNKI up to 20 March 2020. As the results shown, 12 publications with 2389 COVID-19 patients (674 severe cases) were included for the analysis of disease severity. The severity rate of COVID-19 in hypertensive patients was much higher than in non-hypertensive cases (37.58% vs 19.73%, pooled OR: 2.27, 95% CI: 1.80–2.86). Moreover, the pooled ORs of COVID-19 severity for hypertension vs. non-hypertension was 2.21 (95% CI: 1.58–3.10) and 2.32 (95% CI: 1.70–3.17) in age <50 years and ⩾50 years patients, respectively. Additionally, six studies with 151 deaths of 2116 COVID-19 cases were included for the analysis of disease fatality. The results showed that hypertensive patients carried a nearly 3.48-fold higher risk of dying from COVID-19 (95% CI: 1.72–7.08). Meanwhile, the pooled ORs of COVID-19 fatality for hypertension vs. non-hypertension was 6.43 (95% CI: 3.40–12.17) and 2.66 (95% CI: 1.27–5.57) in age <50 years and ⩾50 years patients, respectively. Neither considerable heterogeneity nor publication bias was observed in the present analysis. Therefore, our present results provided further evidence that hypertension could significantly increase the risks of severity and fatality of SARS-CoV-2 infection.