Dual-additive-based electrolyte design for aqueous zinc ion batteries with high plating/stripping efficiency.

A dual-additive-based aqueous electrolyte was designed with a pH-buffering additive (Zn(OAc)2) and an electrostatic shielding additive (TMAOAc) for high Zn plating/stripping efficiency. The buffering pair, OAc-/HOAc, can stabilize the pH value to suppress side hydrogen evolution reactions. Meanwhile, TMA+ acts as a competitive cation being preferentially adsorbed on the uneven surface of the Zn anode and exerts an electrostatic shielding effect to facilitate flat Zn deposition. Such a dual-additive-based electrolyte promotes an ultra-high Zn plating/stripping efficiency of 99.9% at 1 mA cm-2 and long-term cycling stability for 3600 h at 0.5 mA cm-2, offering valuable insights for advanced aqueous batteries.

High Power- and Energy-Density Supercapacitors through the Chlorine Respiration Mechanism.

Supercapacitor represents an important electrical energy storage technology with high-power performance and superior cyclability. However, currently commercialized supercapacitors still suffer limited energy densities. Here we report an unprecedentedly respiring supercapacitor with chlorine gas iteratively re-inspires in porous carbon materials, that improves the energy density by orders of magnitude. Both electrochemical results and theoretical calculations show that porous carbon with pore size around 3 nm delivers the best chlorine evolution and adsorption performance. The respiring supercapacitor with multi-wall carbon nanotube as the cathode and NaTi2 (PO4 )3 as the anode can store specific energy of 33 Wh kg-1 with negligible capacity loss over 30 000 cycles. The energy density can be further improved to 53 Wh kg-1 by replacing NaTi2 (PO4 )3 with zinc anode. Furthermore, thanks to the extraordinary reaction kinetics of chlorine gas, this respiring supercapacitor performs an extremely high-power density of 50 000 W kg-1 .

Serial Interval and Reproductive Number of COVID-19 Among 116 Infector-infectee Pairs - Jingzhou City, Hubei Province, China, 2020.

WHAT IS ALREADY KNOWN ABOUT THIS TOPIC?: The key epidemiological parameters including serial interval, basic reproductive number (R 0), and effective reproductive number (R t) are crucial for coronavirus disease 2019 (COVID-19) control and prevention. Previous studies provided different estimations but were often flawed by some limitations such as insufficient sample size and selection bias. WHAT IS ADDED BY THIS REPORT?: In this study, a total of 116 infector-infectee pairs meeting strict inclusion criteria were selected for analysis. The mean serial interval of COVID-19 was 5.81 days (standard deviation: 3.24). The estimated mean with 95% confidence interval of R 0 was 3.39 (3.07-3.75) and 2.98 (2.62-3.38) using exponential growth (EG) and maximum likelihood (ML) methods, respectively. The R t in the early phase of the epidemic was above 1 with the peak of 4.43 occurring on January 8, and then showing subsequent declines and approaching 1 on January 24. WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICES?: This study supports previous findings that COVID-19 has high transmissibility and that implementing comprehensive measures is effective in controlling the COVID-19 outbreak.