Ion conduction path in composite solid electrolytes for lithium metal batteries: from polymer rich to ceramic rich

Solid-state electrolytes(SSEs)can address the safety issue of organic electrolyte in rechargeable lithium batteries.Unfortunately,neither polymer nor ceramic SSEs used alone can meet the demand although great progress has been made in the past few years.Composite solid electrolytes(CSEs)composed of flexible polymers and brittle but more conducting ceramics can take advantage of the individual system for solid-state lithium metal batteries(SSLMBs).CSEs can be largely divided into two categories by the mass fraction of the components:“polymer rich”(PR)and“ceramic rich”(CR)systems with different internal structures and electrochemical properties.This review provides a comprehensive and in-depth understanding of recent advances and limitations of both PR and CR electrolytes,with a special focus on the ion conduction path based on polymer-ceramic interaction mechanisms and structural designs of ceramic fillers/frameworks.In addition,it highlights the PR and CR which bring the leverage between the electrochemical property and the mechanical property.Moreover,it further prospects the possible route for future development of CSEs according to their rational design,which is expected to accelerate the practical application of SSLMBs.

Using Three-Dimensional Lorenz Scatter Plots to Detect Patients with Atrioventricular Node Double Path Caused by Interpolated Ventricular Premature Systoles: A Case Study

A series of related electrophysiology phenomena can be caused by the occurrence of interpolated ventricular premature contraction.In our recent three-dimensional Lorenz R-R scatter plot research,we found that atrioventricular node double path caused by interpolated ventricular premature contraction imprints a specifi c pattern on three-dimensional Lorenz plots generated from 24-hour Holter recordings.We found two independent subclusters separated from the interpolated premature beat precluster,the interpolated premature beat cluster,and the interpolated premature beat postcluster,respectively.Combined with use of the trajectory tracking function and the leap phenomenon,our results reveal the presence of the atrioventricular node double conduction path.

High-performance PVDF-HFP based gel polymer electrolyte with a safe solvent in Li metal polymer battery

Poly(vinylidenefluoride-co-hexafluoropropylene)(PVDF-HFP)based gel polymer electrolytes are widely studied owing to their electrochemical stability and high dielectric constant.However,most gel polymer electrolytes show unsatisfied safety and interface compatibility due to excessive absorption of volatile and flammable liquid solvents.Herein,by using a safe solvent(N-methyl-2-pyrrolidone)with higher boiling(203℃)and flash points(95℃),we initiatively fabricate a flexible PVDF-HFP based gel polymer electrolyte.The obtained gel polymer electrolyte demonstrates a high ionic conductivity of 7.24×10^−4 S cm−1,an electrochemical window of 5.2 V,and a high lithium transference number of 0.57.As a result,the synthesized polymer electrolyte exhibits a capacity retention of 70%after 500 cycles at 0.5 C,and a discharge capacity of 86 mAh g−1 even at a high current rate of 10 C for LiFePO4 based Li metal batteries.Moreover,a stable Li plating/stripping for more than 500 h is achieved under 0.1 mAh at both room temperature and 70℃.Our results indicate that the PVDF-HFP polymer electrolyte is promising for manufacturing safe and high-performance Li metal polymer batteries.

Impact of Environmental Regulation on Industrial Upgrading: Analysis Based on Panel Data of 30 Provinces in China

Environmental regulation and industrial upgrading are the key to achieve win-win results for both economy and the environment. After environmental regulation tools are divided into market incentive and command control types,based on the provincial-level data of 30 provinces( cities and regions) in China from 2004 to 2016,the impact of environmental regulation on industrial upgrading and its transmission paths are empirically tested through an intermediary effect model. Technological innovation,FDI and capital market development all meet intermediary conditions,and the market incentive type is more dependent on technological innovation,while the command control type is more dependent on FDI and capital market development.The impact of the two environmental regulation tools on industrial upgrading is further studied. The results show that there is an " inverted U-shaped" relationship between the command control type and industrial upgrading,while there is a " U-shaped" relationship between the market incentive type and industrial upgrading,and there are also certain regional differences in the impact of environmental regulation on industrial upgrading.

Subthreshold behavior of AlInSb/InSb high electron mobility transistors

We propose a scaling theory for single gate Al In Sb/In Sb high electron mobility transistors（HEMTs） by solving the two-dimensional（2D） Poisson equation. In our model, the effective conductive path effect（ECPE） is taken into account to overcome the problems arising from the device scaling. The potential in the effective conducting path is developed and a simple scaling equation is derived. This equation is solved to obtain the minimum channel potential Φdeff,minand the new scaling factor α to model the subthreshold behavior of the HEMTs. The developed model minimizes the leakage current and improves the subthreshold swing degradation of the HEMTs. The results of the analytical model are verified by numerical simulation with a Sentaurus TCAD device simulator.

The conductive path in HfO_2:first principles study

The conductive path formed by the interstitial Ag or substitutional Ag in Hf02 was investigated by using the Vienna ab initio simulation package based on the DFT theory. The calculated results indicated that the ordering of interstitial Ag ions at special positions can form a conductive path, and it cannot form at other positions.The orientation dependence of this conductive path was then investigated. Various types of super cells are also built to study the rupture of the path, which corresponds to some possible ＂off＂ states.

Improved Control Strategy for Carbonized Cable Preparation in Low-voltage Arc Fault Test

Outdated testing methods hinder the success rate of carbonized cable preparation in low-voltage arc fault tests,leading to incomplete tests and high failure rates.To address this issue,we finely categorized the preparation results of carbonized cable specimens by analyzing the experimental phenomena during the carbonization process and assessing the impact of high-voltage energization time on the outcomes,presenting a process control strategy aimed at optimizing the preparation results of carbonized cable specimens.This method utilizes three periodic moving algorithms(root-mean-square,average,and shoulder percentage)to classify the cable specimens into four preparation categories:open-circuit carbonization,under-carbonization,short-circuit carbonization,and successful carbonization.The high-voltage energization time during carbonization or secondary carbonization was adjusted to optimize the preparation of the carbonized cables by considering different discrimination outcomes.Finally,the proposed method was tested on a purpose-built carbonized cable experimental platform,which confirmed its effectiveness in differentiating the preparation outcomes of the carbonized cable specimens and improving the success rate of the carbonized cable preparation.The proposed method has significant potential for application in low-voltage arc fault test systems.

Thermal time-constant spectrum extraction method in AlGaN/GaN HEMTs

The transient temperature rise in the active region in AlGaN/GaN high electron mobility transistors （HEMTs） is measured using an electrical method. The original data are smoothed and denoised by a nonparametric fitting algorithm, called locally weighted scatterplot smoothing （LOWESS）. The thermal time-constant spectrum is extracted to analyze the physical structure of the heat-conduction path in A1GaN/GaN HEMTs. The thermal time- constant spectra extracted using the LOWESS algorithm are richer and the RC network obtained is greater compared with those with the traditional denoising method （multi-exponential fitting）. Thus, the analysis of the heat-flow path is more precise. The results show that the LOWESS nonparametric fitting algorithm can remove noise from measured data better than other methods and can retain the subtle variation tendency of the original discrete data. The thermal time-constant spectra extracted using this method can describe the subtle temperature variations in the A1GaN/GaN HEMT active region. This will help researchers to precisely analyze the layer composition of the heat-flow path.

Physical mechanism of resistance switching in the co-doped RRAM

The physical mechanism of the resistance switching for RRAM with co-doped defects（Ag and oxygen vacancy）is studied based on the first principle calculations and the simulation tool VASR The interaction energy,formation energy and density of states of Ag and oxygen vacancy defect（VO）are calculated.The calculated results reveal that the co-doped system is more stable than the system only doped either Ag or VO defect and the impurity energy levels in the band gap are contributed by Ag and VO defects.The obtained partial charge density confirmed further that the clusters are obvious in the direction of Ag to Hf ions,which means that it is Ag but VO plays a role of conductive paths.For the formation mechanism,the modified electron affinity and the partial charge density difference are calculated.The results show that the ability of electron donors of Ag is stronger than VO In conclusion,the conductivity of the physical mechanism of resistance switching in the co-doped system mainly depends on the doped Ag.