Investigation of sodium vanadate as a high-performance aqueous zinc-ion battery cathode

Due to the intrinsic advantages of nontoxicity, low-cost, and abundant resource of metallic zinc, aqueous zinc-ion batteries (ZIBs) have attracted universal interest [1,2]. Tremendous cathode materials have been exploited in aqueous ZIBs, such as manganese-based materials [3-11], Co-based materials [12,13] and vanadium-based materials [14-21].

Synthesis of Schiff Base Calix[4]arene Crowns

This letter reports the synthesis of Schiff base calix[4]arene crowns containing m-xylylene phenol subunit, in which calix[4]arene Schiff base crowns 2a, 2b and 2c were formed by 1:1 condensation of calix[4]arene diamine 1 with dialdehydes (2, 6-diformyl-4-chlorophenol 3a, 2, 6-diformyl-4-methylphenol 3b, 2, 6-diformyl-4-tert-butylphenol 3c) under high dilute condition in refluxing anhydrous ethanol in 65-70% yield.

Interfacial Behaviors of Azocalixarene Derivatives at the Air/Water Interface and Photochromism in the Langmuir-Blodgett Films

The interfacial behaviors of the non-typical amphiphilic compound p-methylphenylazocalix[4]arene 1 and p-chlorophenylazocalix[4]arene 2 at the air/water interface and photochromism in the Langmuir-Blodgett films were studied by surface pressure-area isotherm and UV-Vis spectra. The results indicate that they can form stable monolayers at the air / water interface although they have no hydrophobic alkyl chains, and their LB film underwent reversible trans-cis photoisomerization on UV and daylight illumination.

浅论同步电机可控硅整流装置的选型

目前,同步电机的励磁系统大多采用可控硅(晶闸管)进行整流,可控硅功率整流回路的设计选型,不仅关系到整流装置本身的安全也关系到发电机乃至电网的安全。从运行角度出发,期望对阳极电压的选择在满足电力系统稳定要求的同时,应兼顾到不至于影响和危及到整流装置安全运行的各种因素。合理的选择强励倍数是整流装置安全、经济、合理运行的重要因素。

Development of an electronic stopping power model based on deep learning and its application in ion range prediction

Deep learning algorithm emerges as a new method to take the raw features from large dataset and mine their deep implicit relations,which is promising for solving traditional physical challenges.A particularly intricate and difficult challenge is the energy loss mechanism of energetic ions in solid,where accurate prediction of stopping power is a longtime problem.In this work,we develop a deep-learning-based stopping power model with high overall accuracy,and overcome the long-standing deficiency of the existing classical models by improving the predictive accuracy of stopping power for ultra-heavy ion with low energy,and the corresponding projected range.This electronic stopping power model,based on deep learning algorithm,could be hopefully applied for the study of ion-solid interaction mechanism and enormous relevant applications.

A semi-classical model for the charge exchange and energy loss of slow highly charged ions in ultrathin materials

We present a simple and reliable method,based on the over-barrier model and Lindhard’s formula,to calculate the energy loss,charge transfer,and normalized intensity of highly charged ions penetrating through 2D ultrathin materials,including graphene and carbon nanomembranes.According to our results,the interaction between the ions and the 2D material can be simplified as an equivalent two-body collision,and we find that full consideration of the charge exchange effect is key to understanding the mechanism of ion energy deposition in an ultrathin target.Not only can this semiclassical model be used to evaluate the ion irradiation effect to a very good level of accuracy,but it also provides important guidance for tailoring the properties of 2D materials using ion beams.

Metal/covalent organic frameworks for aqueous rechargeable zinc-ion batteries

Lithium-ion batteries(LIBs)have become one of the most successful energy storage systems due to their high operating voltage,high energy density,and long cycle life.However,with the widespread use of LIBs in recent decades,lithium resources are at risk of being exhausted.Therefore,it is necessary to find a substitute for LIBs to meet the needs of future large-scale energy storage systems.Because of their competitiveness,low cost,and high safety,aqueous rechargeable zinc-ion batteries(ARZIBs)are regarded as promising components in the post-lithium-ion-battery era.Given the tunable composition,ordered porous channels,and controllable structure of metal-organic frameworks(MOFs)and covalent organic frameworks(COFs),these frameworks are viewed as potential materials for developing high-performance ARZIBs.In this review,we focus on the recent developments in the applications of MOF-/COF-based materials in ARZIBs,including in electrode materials,anode modifications,separators,and solid electrolytes.We then focus on the critical factors and optimization techniques of MOF-/COF-based materials that affect the performance of ARZIBs.Finally,we conclude with some projections for the expansion of ARZIBs containing MOF-/COF-based materials.

锌负极和锂负极在不同温度下的电化学行为

本文研究表明锂金属负极的枝晶问题在较低温度下会加剧,在较高温度下会受到抑制;而对于水系可充电锌基电池中锌金属负极的枝晶演变,温度的影响则恰恰相反.对两种负极的电化学行为的研究结果表明,界面反应速率和离子扩散率的匹配程度以及副反应综合影响了金属负极的枝晶生长和循环寿命.研究发现有机电解质和水电解质在上述影响因素上的不同性质导致相反的温度影响.本文进一步对混合电解质(有机和水性)进行了详细研究,以调节离子扩散率和副反应,同时扩大水系可充锌基电池的工作温度窗口.本文揭示了有机锂金属负极和水系锌基电池完全相反的温度影响,并揭示了潜在的影响机制,有助于加深对金属负极的理解,从而促进水系锌基电池的大规模应用.

Strategies of binder design for high-performance lithium-ion batteries:a mini review

Developing high-performance lithium-ion batteries (LIBs) with high energy density, rate capability and long cycle life are essential for the ever-growing practical application. Among all battery components, the binder plays a key role in determining the preparation of electrodes and the improvement of battery performance, in spite of a low usage amount. The main function of binder is to bond the active material, conductive additive and current collector together and provide electron and ion channels to improve the kinetics of electrochemical reaction. With the ever-increasing requirement of high energy density by LIBs, technical challenges such as volume expansion and active material dissolution are attracting worldwide attentions, where binder is thought to provide a new solution.There are two main categories (organic solvent soluble binder and water-soluble binder) and abundant polar functional groups providing adhesion ability. It is of great significance to timely summarize the latest progress in battery binders and present the principles for designing novel binders with both robust binding interaction and outstanding electrode stabilization function. This review begins with an introduction of the binding mechanism and the related binding forces, including mechanical interlocking forces and interfacial forces. Then, we discussed four different strategies (the enhancement of binding force,the formation of three-dimensional (3D) network, the enhancement of conductivity and binders with special functions) for constructing ideal binder system in order to satisfy the specific demands of different batteries, such as LIBs and lithium–sulfur (Li–S) batteries. Finally, some prospective and promising directions of binder design are proposed based on the existing and emerging binders and guide the development of the next-generation LIBs.

High capacity lithium-manganese-nickel-oxide composite cathodes with low irreversible capacity loss and good cycle life for lithium ion batteries

We report a method to eliminate the irreversible capacity of 0.4Li_2MnO_3·0.6LiNi_(0.5)Mn_(0.5)O_2(Li_(1.17)Ni_(0.25)Mn_(0.583)O_2) by decreasing lithium content to yield integrated layered-spinel structures.XRD patterns,High-resolution TEM image and electrochemical cycling of the materials in lithium cells revealed features consistent with the presence of spinel phase within the materials.When discharged to about 2.8 V,the spinel phase of LiM_2O_4(M=Ni,Mn) can transform to rock-salt phase of Li_2M_2O_4(M=Ni,Mn) during which the tetravalent manganese ions are reduced to an oxidation state of 3.0.So the spinel phase can act as a host to insert back the extracted lithium ions(from the layered matrix) that could not embed back into the layered lattice to eliminate the irreversible capacity loss and increase the discharge capacity.Their electrochemical properties at room temperature showed a high capacity(about 275 mAh g^(-1) at 0.1 C) and exhibited good cycling performance.

Characterization of Bacillus phage Gxv1,a novel lytic Salasvirus phage isolated from deep-sea seamount sediments

Seamounts are hotspots for marine life,but to date,no bacteriophages have been reported.Here,a novel Bacillus podophage(named as Bacillus phage Gxv1)was isolated from deep-sea seamount sediments of the western Pacifc Ocean(~5790 m).Phage Gxv1 has a hexameric head~42–53 nm in diameter and a short tail of~30 nm long,which is a typical feature of the Podoviridae family.One-step curve analysis showed that Gxv1 is a lytic phage that can initiate host lysis within 3.5 h postinfection,and has a relatively large burst size.The 21,781-bp genome contains 34 predicted genes,and the G+C content of phage Gxv1 is 39.69%.Whole-genome comparison of phage Gxv1 with known bacteriophages,using BlastN analysis against the IMG/VR database,revealed that phage Gxv1 is closely related to Bacillus phage phi29 that infects Bacillus subtilis,and their genome-wide similarity is 93.62%.Phylogenetic analysis based on DNA polymerase showed that phage Gxv1 belongs to the Salasvirus genus.Multiple genome alignment showed that phage Gxv1 shares a high level of sequence similarity and common gene order with Bacillus phage phi29.However,some sequences are unique to phage Gxv1,and this region contains genes encoding DNA packing protein,DNA replication protein,and unknown protein.These sequences exhibit low sequence similarity to known bacteriophages,highlighting an unknown origin of these sequences.This study will help improve our understanding of the Salasvirus genus and phage diversity in deep-sea seamounts.