Engineering a flexible and mechanically strong composite electrolyte for solid-state lithium batteries

Lithium-ion batteries(LIBs)have greatly facilitated our daily lives since 1990s[1,2].To meet the ever-increasing demand on energy density,Li metal is seen as the ultimate anode because of its ultra-high specific capacity(3860 m Ah/g)and the lowest electrochemical potential(-3.04 V vs.the standard hydrogen electrode)[3–6].However,issues of Li metal anode,such as Li dendrite formation and large volume change during plating/stripping。

Review and prospect of the effects of freeze-thaw on soil geotechnical properties

Freeze-thaw hazard is one of the main problems in cold regions engineering and artificial ground freezing engineering.To mitigate freeze-thaw hazards,it is essential to investigate the effects of freeze-thaw on soils engineering properties.This paper summarizes the effects of freeze-thaw on the physical and mechanical properties of soils reported in recent studies.The differences of freeze-thaw conditions between freezing shaft sinking and cold regions engineering are discussed.Based on the technological characteristics of freezing shaft sinking in deep alluvium,we further attempt to identify key research needs regarding the freeze-thaw effects on the engineering properties of deep soils.

Downregulation of cardiac PIASy inhibits Cx43 SUMOylation and ameliorates ventricular arrhythmias in a rat model of myocardial ischemia/reperfusion injury

Background:Dysfunction of the gap junction channel protein connexin 43(Cx43)contributes to myocardial ischemia/reperfusion(I/R)-induced ventricular arrhythmias.Cx43 can be regulated by small ubiquitin-like modifier(SUMO)modification.Protein inhibitor of activated STAT Y(PIASy)is an E3 SUMO ligase for its target proteins.However,whether Cx43 is a target protein of PIASy and whether Cx43 SUMOylation plays a role in I/R-induced arrhythmias are largely unknown.Methods:Male Sprague-Dawley rats were infected with PIASy short hairpin ribonucleic acid(shRNA)using recombinant adeno-associated virus subtype 9(rAAV9).Two weeks later,the rats were subjected to 45 min of left coronary artery occlusion followed by 2 h reperfusion.Electrocardiogram was recorded to assess arrhythmias.Rat ventricular tissues were collected for molecular biological measurements.Results:Following 45 min of ischemia,QRS duration and QTc intervals statistically significantly increased,but these values decreased after transfecting PIASy shRNA.PIASy downregulation ameliorated ventricular arrhythmias induced by myocardial I/R,as evidenced by the decreased incidence of ventricular tachycardia and ventricular fibrillation,and reduced arrythmia score.In addition,myocardial I/R statistically significantly induced PIASy expression and Cx43 SUMOylation,accompanied by reduced Cx43 phosphorylation and plakophilin 2(PKP2)expression.Moreover,PIASy downregulation remarkably reduced Cx43 SUMOylation,accompanied by increased Cx43 phosphorylation and PKP2 expression after I/R.Conclusion:PIASy downregulation inhibited Cx43 SUMOylation and increased PKP2 expression,thereby improving ventricular arrhythmias in ischemic/reperfused rats heart.

Copper fluoride as a low-cost sodium-ion battery cathode with high capacity

Sodium-ion batteries (SIBs) are promising alternatives to lithium-ion batteries (LIBs) for large-scale energy storage considering the abundance and low cost of Na-containing resources. However, the energy density of SIBs has been limited by the typically low specific capacities of traditional intercalation-based cathodes. Metal fluorides, in contrast, can deliver much higher capacities based on multi-electron conversion reactions. Among metal fluorides, CuF_(2) presents a theoretical specific capacity as high as 528 mAh/g while its Na-ion storage mechanism has been rarely reported. Here, we report CuF_(2) as a SIB cathode, which delivers a high capacity of 502 mAh/g but suffers from poor electrochemical reversibility. As a solution, we adjust the cell configuration by inserting a carbon-coated separator, which hinders the transportation of dissolved Cu ions and improves the reversibility of the CuF_(2) cathode. By using in-situ XRD measurements and theoretical calculation, we propose that a one-step conversion reaction occurs during the discharge process, and a reconversion reaction competes with the oxidization of Cu to dissolved Cu ion during the charge process.