In situ induced cation-vacancies in metal sulfides as dynamic electrocatalyst accelerating polysulfides conversion for Li-S battery

Cation vacancy engineering is considered to be one of the effective methods to solve the issues of shuttling and sluggish redox kinetics of Li PSs owing to the intrinsic tunability of electronic structure.However,cation vacancies are few studied in the Li-S realm due to their complex and rigid preparation methods.In this work,one-step pyrolysis is reported to in situ introduce Fe-vacancies into iron sulfide(Fe_(0.96)S)as a sulfur host.For this host structure,Fe_(0.96)S is first employed as an adsorbent and catalyst in Li-S system.During the carbonization process,a tight contact structure of Fe_(0.96)S crystal and carbon network(Fe_(0.96)S@C)is in situ constructed,and the carbon layer as a conductor provides smooth electrons transfer pathways for redox reactions.Meanwhile,due to the introduction of Fe-vacancies in Fe S crystal,the adsorption capability and catalytic effect for Li PSs have been substantially enhanced.Moreover,the presence of Fe_(0.96)S crystal favors the mobility of electron and diffusion of Li+,which is revealed by the experiments and theoretical calculations.Through synergy respective advantages effect of Fe_(0.96)S and carbon,the Fe_(0.96)S@C-S cathode delivers high-rate capability at 5.0 C and stable long-life performance.Even under a high sulfur loading of 3.5 mg/cm^(2),the durable cyclic stability is still exhibited with the capacity retention of 93%over 400 cycles at 1.0 C,and the coulombic efficiency is≥98%.Noting that this strategy greatly simplifies the synthetic process of currently known cation-vacancy materials and furnishes a universal mentality for designing both divinable and astonishing new cation-vacancy materials.

The presence of foci of Rickettsia conorii infection in China

China is not considered as an endemic area of Rickettsia conorii,so there is no routine clinical way to diagnose this infection.This study aims to determine whether 2 febrile patients who had a tick bite in East China were indeed infected with R.conorii.The citrate synthase gene(gltA)was amplified with universal rickettsial primers by real-time fluorescent PCR from the patients’blood samples.Nested PCR was used to amplify the outer membrane protein A gene(ompA)for positive specimens.PCR products were further identified and analyzed through nucleic acid sequencing.Positive amplification of the gltA and ompA genes was found in both patients.The nucleotide sequences(303 bp)of the ompA gene of the 2 patients had high homology(99%)with the R.conorii Indian tick typhus strain in GenBank.A more than 4-fold increase in IgG against R.conorii provided supportive evidence of SFG Rickettsia infection.And the rapid recovery after doxycycline treatment also supported a rickettsial cause for the disease.Physicians in East China should be aware of human infections with R.conorii.PCR-based diagnostic methods offer a rapid and precise way to diagnose rickettsiosis,improving patient identification and management.