Polymer “Tape”-Assisted Ball-Milling Method Fabrication Few-Atomic-Layered Bismuth for Improving K^(+)/Na^(+)Storage

Few-layered 2D analogs exhibit new physical/chemical properties,leading to a strong research interest and broad areas of application.Recently,lots of methods(such as ultrasonic and electrochemical methods)have already used to prepared 2D materials.However,these methods suffer from the drawbacks of low yield,high cost,or precarious state,which limit the largescale applications.Inspired by the famous Scotch tape method,we develop a ball-milling with polymer"tape"method,fabricating few-atomic-layered material,showing the high-yield,low-cost,and much stability.As electrode material,ultrathin 2D materials can shorten the ion transfer pathway,contributing to the development of high-power batteries.Meanwhile,fewatomic-layered structure can expose more active sites to increase their capacity,showing special energy storage mechanism.We use the as-prepared few-atomic-layered Bi(FALB)and reduced oxide graphene composites as the anode for potassium/sodium-ion batteries(KIBs/NIBs).The sample achieves a high reversible capacity of 395 m Ah g^(-1)for KIBs,of which FALB contributes 438 m Ah g^(-1)(higher than the theoretical capacity of Bi,386 m Ah g^(-1)),and it carries outstanding cycle and rate performance in KIBs/NIBs.

Boosting Li-ion storage in Li2MnO_(3) by unequal-valent Ti4+-substitution and interlayer Li vacancies building

Lithium rich layered oxide(LRLO) has been considered as one of the promising cathodes for lithium-ion batteries(LIBs). The high voltage and large capacity of LRLO depend on Li2MnO_(3)phase. To ameliorate the electrochemical performance of Li2MnO_(3), also written as Li(Li1/3Mn2/3)O_(2), we propose a strategy to substitute Mn4+and Li+in Mn/Li transition metal layer with Ti4+, which can stabilize the structure of Li2MnO_(3)by inhibiting the excessive oxidation of O_(2)-above 4.5 V. More significantly, the unequal-valent substitution brings about the emergence of interlayer Li vacancies, which can promote the Li-ion diffusion based on the enlarged interlayer and increase the capacity by activating the Mn3+/4+redox. We designed Li0.7[Li1/3Mn2/3]0.7Ti0.3O_(2)with high interlayer Li vacancies, which presents a high capacity(290 m Ah/g at 10 m A/g) and stable cycling performance(84% over 60 cycles at 50 m A/g). We predict that this strategy will be helpful to further improve the electrochemical performance of LRLOs.

Effects on the thermal expansion coefficient and dielectric properties of CLST/PTFE filled with modified glass fiber as microwave material

Ceramic and polytetrafluoroethylene composites as dielectric materials have a low dielectric loss at high frequency and play an important role in the modern communication field.However,room temperature phase transformation of PTFE resins,which is accompanied by a large volume change(>400 ppm/℃),seriously affects the dimensional stability and performance stability of materials.The LD125 modified glass fiber(GF)was introduced to the CaO-Li2 O-Sm2O3-TiO2(CLST)/PTFE composite,to reduce the thermal expansion coefficient(CTE)of the composites.The tri-phase composites(CLST/PTFE/GF)show the low dielectric loss and excellent machine-ability.The effect of GF content on the dielectric properties and CTE was also investigated.The CLST/PTFE filled with 5%GF exhibits the best overall performance,which is a promising microwave dielectric material for microwave communication.

Low-coordination water Prussian white as cathode for high-performance potassium-ion batteries

Prussian whites(PWs) with a three-dimensional framework can accommodate the insertion and extraction of ions with large radius,which have been widely used in potassium ion batteries.However,PWs show the poor cycling performance and inferior rate ability because of high coordinated water.In this work,PWs with different water content were synthesized via a coprecipitation method by controlling the reaction temperature.The sample with low-coordination water prohibits the best electrochemical performance.It shows a high capacity of 120.5 mAh/g at 100 mA/g for potassium-ion batteries(KIBs).It also exhibits a good rate performance,displaying a capacity of 73.2 mAh/g at 500 mA/g.