Diverse Structural Design Strategies of MXene‑Based Macrostructure for High‑Performance Electromagnetic Interference Shielding

There is an urgent demand for flexible,lightweight,mechanically robust,excellent electromagnetic interference(EMI)shielding materials.Two-dimensional(2D)transition metal carbides/nitrides(MXenes)have been potential candidates for the construction of excellent EMI shielding materials due to their great electrical electroconductibility,favorable mechanical nature such as flexibility,large aspect ratios,and simple processability in aqueous media.The applicability of MXenes for EMI shielding has been intensively explored;thus,reviewing the relevant research is beneficial for advancing the design of high-performance MXene-based EMI shields.Herein,recent progress in MXene-based macrostructure development is reviewed,including the associated EMI shielding mechanisms.In particular,various structural design strategies for MXene-based EMI shielding materials are highlighted and explored.In the end,the difficulties and views for the future growth of MXene-based EMI shields are proposed.This review aims to drive the growth of high-performance MXene-based EMI shielding macrostructures on basis of rational structural design and the future high-efficiency utilization of MXene.

暑期支教作为化学师范生实践课程的育人研究——以北京师范大学“化育英才”暑期支教队为例

北京师范大学化学学院对化学专业公费师范生的培养目标是面向全国各级各类中学培养卓越化学教师,并将“社会实践与志愿服务”作为公费师范生的实践课程之一。学生开展暑期支教项目,是参加社会实践与志愿服务的一种常见形式。本文以北京师范大学化学学院“化育英才”暑期支教队为例,证明通过重视暑期支教指导教师的指导作用,保障学生实践时间和质量,将学生自身成长与服务社会相统一,将实践内容与开设的其他课程相互补,在实践中体现知识的应用与学习相统一,不仅能使暑期支教项目成为化学专业公费师范生的实践类金课,而且能为化学专业公费师范生未来教师职业发展打下一定的基础。

Biopolymer-Based Aerogels for Electromagnetic Wave Shielding and Absorbing

The rapid development of communication technology and electronic industry has brought unprecedented serious electromagnetic interference(EMI)and electromagnetic wave(EMW)pollution.Although EMI shields and EMW absorbers based on metal or magnetic materials were used to solve these problems,they have long been criticized for their high price,high density and easy corrosion.In order to achieve low density and efficient dissipation of electromagnetic energy,aerogels stand out among manifold materials.However,constructing aerogels with good EMI shielding or EMW absorption performance and acceptable mechanical properties is not an easy task.Burgeoning biopolymers,such as cellulose,lignin,chitin/chitosan and alginate,breathe new life into aerogels for high-efficiency EMW shielding and absorbing.Here,we reviewed the contributions of biopolymers in the fields of aerogels for EMW shielding and absorbing.At the same time,some challenges and outlook were also pointed out,aiming to promote the advance of aerogel-based EMI shields and EMW absorbers as well as the rational utilization of biopolymers.

Hydrogel-based composites beyond the porous architectures for electromagnetic interference shielding

With the rapid development of the electronic industry and wireless communication technology,electromagnetic interference(EMI)or pollution has been increasingly serious.This not only severely endangers the normal operation of electronic equipment but also threatens human health.Therefore,it is urgent to develop high-performance EMI shielding materials.The advent of hydrogel-based materials has given EMI shields a novel option.Hydrogels combined with conductive functional materials have good mechanical flexibility,fatigue durability,and even high stretchability,which are beneficial for a wide range of applications,especially in EMI shielding and some flexible functional devices.Herein,the current progress of hydrogel-based EMI shields was reviewed,in the meanwhile,some novel studies about pore structure design that we believe will help advance the development of hydrogel-based EMI shielding materials were also included.In the outlook,we suggested some promising development directions for the hydrogel-based EMI shields,by which we hope to provide a reference for designing hydrogels with excellent EMI shielding performance and multifunctionalities.

三维多孔碳基吸波材料的研究进展

随着电磁波(EMW)污染的日益严重,开发高性能电磁波吸收材料(EWAMs)已成为研究热点.碳基EWAMs具有优异的物理、化学稳定性和高导电性带来的强介电损耗.特别是三维(3D)多孔碳基EWAMs在EMW吸收研究领域长盛不衰.3D多孔结构大大降低了材料的密度,有利于EMW的多次反射和散射,优化了阻抗匹配,因此有望实现“低密度、薄厚度、宽吸收带宽、强吸收”的目标.在此,我们首先阐明了相关的理论基础和评价方法.之后,我们以材料来源为主线索,总结了3D多孔碳基EWAMs的最新研究进展,并突出了其中一些独特而新颖的观点.最后,提出了3D多孔碳基EWAMs的挑战和前景,这将有助于高性能EWAMs的进一步发展.