Revealing the correlation between structure evolution and electrochemical performance of high-voltage lithium cobalt oxide

Lithium cobalt oxide(LCO)is the dominating cathode materials for lithium-ion batteries(LIBs)deployed in consumer electronic devices for its superior volumetric energy density and electrochemical performances.The constantly increasing demands of higher energy density urge to develop high-voltage LCO via a variety of strategies.However,the corresponding modification mechanism,especially the influence of the long-and short-range structural transitions at high-voltage on electrochemical performance,is still not well understood and needs further exploration.Based on ss-NMR,in-situ X-ray diffraction,and electrochemical performance results,it is revealed that the H3 to H1-3 phase transition dictates the structural reversibility and stability of LCO,thereby determining the electrochemical performance.The introduction of La and Al ions could postpone the appearance of H1-3 phase and induce various types of local environments to alleviate the volume variation at the atomic level,leading to better reversibility of the H1-3 phase and smaller lattice strain,and significantly improved cycle performance.Such a comprehensive long-range,local,and electronic structure characterization enables an in-depth understanding of the structural evolution of LCO,providing a guiding principle for developing high-voltage LCO for high energy density LIBs.

Lynch syndrome pre-screening and comprehensive characterization in a multi-center large cohort of Chinese patients with colorectal cancer

Objective:Lynch syndrome(LS)pre-screening methods remain under-investigated in colorectal cancers(CRCs)in Asia.Here,we aimed to systematically investigate LS pre-screening and comprehensively characterize LS CRCs.Methods:Microsatellite instability(MSI)and germline variants of DNA mismatch repair(MMR)genes were examined in 406 deficient MMR(dMMR)and 250 proficient MMR CRCs.The genetic differences between LS and sporadic CRCs were studied with whole exome sequencing analysis.Results:The incidence of dMMR in Chinese patients with CRCs was 13.8%.Consistency analysis between MMR immunohistochemistry(IHC)and MSI testing showed the kappa value was 0.758.With next-generation sequencing(NGS),germline variants were detected in 154 CRCs.Finally,88 patients with CRC were identified as having LS by Sanger sequencing.Among them,we discovered 21 previously unreported pathogenic germline variants of MMR genes.Chinese patients with LS,compared with sporadic CRCs,tended to be early-onset,right-sided,early-stage and mucinous.Overall,the performance of MMR IHC and MSI testing for LS pre-screening was comparable:the area under the ROC curve for dMMR,MSI-H,and MSI-H/L was 0.725,0.750,and 0.745,respectively.dMMR_MSI-H LS and sporadic CRCs showed substantial differences in somatic genetic characteristics,including different variant frequencies of APC,CREBBP,and KRAS,as well as different enriched pathways of VEGF,Notch,TGFβR,mTOR,ErbB,and Rac protein signal transduction.Conclusions:MMR IHC and MSI testing were effective methods for LS pre-screening.The revealed clinical and somatic genetic characteristics in LS CRCs may have the potential to improve the performance of LS pre-screening in combination with dMMR/MSI.

One Case about the Diagnosis and Treatment of Right-Sided Infective Endocarditis without Any Inducement

We present a case of Staphylococcus aurous tricuspid valve endocarditis without any risk factors (intravenous drug users, with pacemaker or central venous lines and with congenital heart disease). Transthoracic echocardiography, as first line examination, showed the vegetations on tricuspid valve. In our case, the diagnosis and treatment of right-sided infective endocarditis without any inducement were extremely difficult. Therefore, once a patient comes out with fever, the blood culture remains positive for gram-positive bacterium, and the infectious location still unknown, then the infective endocarditis should be considered. In addition, surgical measure is also an important therapy for right-sided infective endocarditis.

高比能长寿命锂离子电池电极/电解质界面修饰与调控

高能量密度、长寿命及高安全等性能是锂离子电池研究持续追求的目标和发展方向.电极/电解质界面稳定性是制约高比能量长寿命锂离子电池实用化的关键因素.本文针对发展高电压/高能量密度电池体系所面临的挑战,重点总结回顾了本研究团队在过去15年里在正极/电解液界面调控、负极/电解液界面调控、高安全阻燃电解液技术开发,以及固体电解质的结构/界面稳定性调控方面的若干探索性研究工作,并提出了高电压、高安全液体电解液技术和固态电解质及其界面研究为未来该领域的研究重点.

A newly-designed self-powered electrochromic window

By converting incident light into electric power,self-powered electrochromic window(SP-ECW)can achieve color change in electrochromic layer with no need for external voltage.In this work,a newly-de signed SP-ECW is proposed for altering its color between deep blue and colorless state according to on/off state of incident light.The device consists of a working electrode with planar integration of photovoltaic(PV)and electrochromic(EC)elements on one electrode,a platinum counter electrode and a redox electrolyte comprising Br^-/Br_3^-couple.A high transmittance modulation of 41%at 582 nm is obtained.Electrical energy converted from light is not only sufficient to drive the device,but also can be outputted to the external circuit.

Suppressed oxygen extraction and degradation of LiNixMnyCo2O2 cathodes at high charge cut-off voltages

The capacity degradation mechanism in lithium nickel-manganese-cobalt oxide （NMC） cathodes （LiNi1/3Mn1/3Co1/3O2 （NMC333） and LiNi0.4Mn0.4Co0.2O2 （NMC442）） during high-voltage （cut-off of 4.8 V） operation has been investigated. In contrast to NMC442, NMC333 exhibits rapid structural changes including severe micro-crack formation and phase transformation from a layered to a disordered rock-salt structure, as well as interfacial degradation during high-voltage cycling, leading to a rapid increase of the electrode resistance and fast capacity decline. The fundamental reason behind the poor structural and interracial stability of NMC333 was found to be correlated to its high Co content and the significant overlap between the Co3＋/4＋ t2g and O2- 2p bands, resulting in oxygen removal and consequent structural changes at high voltages. In addition, oxidation of the electrolyte solvents by the extracted oxygen species generates acidic species, which then attack the electrode surface and form highly resistive LiF. These findings highlight that both the structural and interfacial stability should be taken into account when tailoring cathode materials for high voltage battery systems.

A survey of script learning

Script is the structured knowledge representation of prototypical real-life event sequences.Learning the commonsense knowledge inside the script can be helpful for machines in understanding natural language and drawing commonsensible inferences.Script learning is an interesting and promising research direction,in which a trained script learning system can process narrative texts to capture script knowledge and draw inferences.However,there are currently no survey articles on script learning,so we are providing this comprehensive survey to deeply investigate the standard framework and the major research topics on script learning.This research field contains three main topics:event representations,script learning models,and evaluation approaches.For each topic,we systematically summarize and categorize the existing script learning systems,and carefully analyze and compare the advantages and disadvantages of the representative systems.We also discuss the current state of the research and possible future directions.