Design and performance improvement of SiNPs@graphene@C composite with a popcorn structure

Silicon anodes are considered to be the most promising alternatives owing to their theoretical specific capacity,which is almost 10 times higher than that of graphite anodes.However,huge volume changes during charging and discharging affect their interface stability,which strongly limits their application in commercial batteries.Herein,a popcorn-structured silicon-carbon composite(SiNPs@graphene@C),composed of silicon nanoparticles(SiNPs),graphene spheres and pitch-based carbon,is prepared by spraydrying followed by a wet process.The resulting SiNPs@graphene@C composite has good flexibility and elastic-strain capacity due to the graphene substrate,and it possesses macrostructural integrity and mechanical stability during cycling due to the rigid carbon–carbon chemical bonds.As a result,it shows a discharge-specific capacity of 481.3 mAh g^(-1)and a capacity retention of 82.9%after 500 cycles at 1 A g^(-1).Besides,the initial coulomb efficiency is increased from 65.7%to 86.5%by pre-lithiation,which improves the feasibility of commercialising the SiNPs@graphene@C composite.

Effect of temperature on formation and evolution of solid electrolyte in terphase on Si@Graphite@C anodes

Studies on the formati on and evolutio n of the solid electrolyte in terface(SEI)film under different ambient temperatures are important to understand the failure behavior of lithium-ion batteries(LIBs).Herein,in-situ electrochemical impedance spectroscopy(EIS)test is performed on the whole discharge process of Si@Graphite@C/Li cell at 0,25 and 55℃,respectively.Combining with scanning electron microscopy,transmission electron microscopy and X-ray photoelectron spectroscopy characterizations,it is found that the SEI film undergoes a complicated evolution process of pre-formation,self-improvement and gradual decay in succession at 25℃.Besides,due to the dissolution of organo-alkyl lithium at high temperature,the formed film is mainly composed of LiF,Li_(2)CO_(3) and other in organic salts,which helps to decrease the impedance.However,the electrolyte is consumed continuously on the new exposed in terface,leading to the degraded performance of the cell.Moreover,the dyn amic properties of Li^(+) ions are poor at low temperature,though the migration ability of Li^(+) ions in the solid phase can be improved as the cycle goes on.Therefore,the development and application of in-situ EIS tech no logy are expected to become an important means to explain the electrochemical performance of batteries.

Impaired Parahippocampal Gyrus-Orbitofrontal Cortex Circuit Associated with Visuospatial Memory Deficit as a Potential Biomarker and Interventional Approach for Alzheimer Disease

The parahippocampal gyrus-orbitofrontal cortex(PHG-OFC)circuit in humans is homologous to the postrhinal cortex(POR)-ventral lateral orbitofrontal cortex(vlOFC)circuit in rodents.Both are associated with visuospatial malfunctions in Alzheimer’s disease(AD).However,the underlying mechanisms remain to be elucidated.In this study,we explored the relationship between an impaired POR-vlOFC circuit and visuospatial memory deficits through retrograde tracing and in vivo local field potential recordings in 5XFAD mice,and investigated alterations of the PHG-OFC circuit by multi-domain magnetic resonance imaging(MRI)in patients on the AD spectrum.We demonstrated that an impaired glutamatergic POR-vlOFC circuit resulted in deficient visuospatial memory in 5XFAD mice.Moreover,MRI measurements of the PHG-OFC circuit had an accuracy of 77.33%for the classification of amnestic mild cognitive impairment converters versus non-converters.Thus,the PHG-OFC circuit explains the neuroanatomical basis of visuospatial memory deficits in AD,thereby providing a potential predictor for AD progression and a promising interventional approach for AD.

An Infrared Touch System for Automatic Behavior Monitoring

Key requirements of successful animal behavior research in the laboratory are robustness,objectivity,and high throughput,which apply to both the recording and analysis of behavior.Many automatic methods of monitoring animal behavior meet these requirements.However,they usually depend on high-performing hardware and sophisticated software,which may be expensive.Here,we describe an automatic infrared behavior-monitor(AIBM)system based on an infrared touchscreen frame.Using this,animal positions can be recorded and used for further behavioral analysis by any PC supporting touch events.This system detects animal behavior in real time and gives closed-loop feedback using relatively low computing resources and simple algorithms.The AIBM system automatically records and analyzes multiple types of animal behavior in a highly efficient,unbiased,and low-cost manner.