A lean-zinc anode battery based on metal-organic framework-derived carbon

Improving zinc metal(Zn^(0))reversibility and minimizing the N/P ratio are critical to boosting the energy density of Zn^(0) batteries.However,in reality,an excess Zn source is usually adopted to offset the irreversible zinc loss and guarantee sufficient zinc cycling,which sacrifices the energy density and leads to poor practicability of Zn^(0) batteries.To address the above conundrum,here,we report a lean-Zn and hierarchical anode based on metal-organic framework(MOF)-derived carbon,where trace Zn^(0) is pre-reserved within the anode structure to make up for any irreversible zinc source loss.This allows us to construct low N/P ratio Zn^(0) full cells when coupling the lean-Zn anode with Zn-containing cathodes.Impressively,high Zn^(0) reversibility(average Coulombic efficiency of 99.4% for 3000 cycles)and long full-cell lifetime(92% capacity retention after 900 cycles)were realized even under the harsh lean-Zn condition(N/P ratio:1.34).The excellent Zn reversibility is attributed to the hierarchy structure that homogenizes zinc ion flux and electric field distribution,as confirmed by theoretical simulations,which therefore stabilizes Zn^(0) evolution.The lean-Zn anode design strategy will provide new insights into construction of high-energy Zn^(0) batteries for practical applications.

Enhancing Capacitance Performance of Ti3C2Tx MXene as Electrode Materials of Supercapacitor: From Controlled Preparation to Composite Structure Construction

Ti3C2Tx,a novel two-dimensional layer material,is widely used as electrode materials of supercapacitor due to its good metal conductivity,redox reaction active surface,and so on.However,there are many challenges to be addressed which impede Ti3C2Tx obtaining the ideal specific capacitance,such as restacking,re-crushing,and oxidation of titanium.Recently,many advances have been proposed to enhance capacitance performance of Ti3C2Tx.In this review,recent strategies for improving specific capacitance are summarized and compared,for example,film formation,surface modification,and composite method.Furthermore,in order to comprehend the mechanism of those efforts,this review analyzes the energy storage performance in different electrolytes and influencing factors.This review is expected to predict redouble research direction of Ti3C2Tx materials in supercapacitors.

CVD growth of graphene on copper-plated scrap steel without external carbon source

Chemical vapor deposition(CVD)using gaseous hydrocarbon sources has shown great promise for large-scale graphene growth,but high growth temperatures(typically 1000℃)require sophisticated and expensive equipment,which increases graphene production costs.Here,we demonstrate a new approach to produce graphene at low cost from scrap steel sheets treated by thermal evaporation of copper plating,which is a derivative of traditional CVD technology.Without additional carbon sources,graphene film was successfully prepared on copper-coated scrap steel sheets at 820℃.The resulting graphene has few defects and uniform morphology,comparable to CVD graphene grown at 1000℃.Finally,the obtained graphene film is used in combination with an interdigital electrode to detect NO_(2)successfully,showing excellent performance.This technology expands the application of graphene in the manufacture of gas sensing devices and is compatible with traditional microelectronics technology.

Three-dimensional porous graphene sponges assembled with the combination of surfactant and freeze-drying

与表面活化剂和 freeze-drying 的联合，我们开发了二种 graphene 多孔的结构。在一方面，把肥皂水泡的泡沫用作模板，有富有的层次毛孔的三维的多孔的 graphene 海绵被综合了。材料的毛孔包含长度规模的三个层次，包括毫米，测微计和纳米。结构能被改变结冰媒介调节，调整激动人心的率或增加功能的添加剂。由 graphene 氧化物 / 表面活化剂暂停的直接 freeze-drying，在另一方面，有方向性地排列的毛孔的一个多孔的框架被准备。表面活化剂给 graphene 氧化物表的更好的分散，导致一个高特定的表面区域。两个获得的材料展出优秀吸收能力和好压缩性能，提供大量可能的应用程序，例如吸收剂，存储媒介，和搬运人。

Ultra-sensitive graphene strain sensor for sound signal acquisition and recognition

为健全信号获得和识别的一个便携、高精确的传感器从编织的特殊设计的 graphene 的薄电影被制作织物(GWF ) 。在被拉长之上，随机的裂缝的高密度出现在网络，它减少当前的小径，从而增加电阻。因此，这部电影能对人的喉咙作为一个紧张传感器起作用以便测量通过肌肉运动，一个声音是否被生产的讲话。超离频敏感允许由提取声波的签名特征的快速、低频率的讲话采样的实现。在这研究， 26 封英语信，典型汉字和音调的代表性的信号，甚至短语和句子被测试，揭示在电阻的明显、典型的变化。而且， graphene 传感器的电阻变化与预告录下的声音完美地反应了。由把人工智能与数字信号处理相结合，我们期望以后，这个 graphene 传感器将能成功地达成复杂声学的系统和听觉的数据的大数量。

10英寸超大尺寸复合纳米薄膜用于耐温柔性超级电容器（英文）

现有超级电容器的工作温度区间约为150℃,但柔性较差.在实际工作环境中,存在一些极端的温度环境,比如,极寒地区.本文制备了面积高达550cm^2 (常规尺寸的29倍)的石墨烯/碳纳米管/锰氧化物复合薄膜,并将其用于耐温柔性超级电容器.该电极材料的性能取决于复合薄膜中石墨烯、碳纳米管和锰氧化物的比例.此柔性超级电容器可在-20-200°C温度区间内保持良好的电化学性能和柔性,表现出优异的稳定性.本文为复合纳米材料薄膜的大批量制备和适用于宽温度区间的柔性超级电容器的发展奠定了基础.

Enhanced zinc storage performance of mixed valent manganese oxide for flexible coaxial fiber zinc-ion battery by limited reduction control

While manganese-based cathodes have been intensively studied for zinc-ion batteries(ZIBs),the limited rate capability and cycle life have always been a difficult problem to be solved.Here,we report a mixed valent manganese oxide(MnOx)cathode with superior electrochemical performance,which exhibits a high specific capacity of 450 mA h/g at 0.2 C and a satisfactory specific capacity of 158.3 mA h/g at a high rate of 5 C.The mixed cathode system reduces the charge transfer resistance,and show good surface stability and adsorption properties,so it is beneficial for the storage of Zn^(2+).Meanwhile,coaxial fiber ZIBs(CFZIBs)with splendid flexibility are assembled utilizing the elaborately prepared cathode material.The CFZIBs achieve a reversible capacity of 255.8 m A h/g and the capacity retention rate is as high as 80%after 1000 bending deformations.This study provides new opportunities for designing ZIBs with high performance and high flexibility.

Tailoring Bi_(2)Te_(3) edge with semiconductor and metal properties under electron beam irradiation

In pursuit of miniaturization in the semiconductor industry,two-dimensional(2D)materials are used to fabricate new electronic devices.The topological insulator(TI)material bismuth telluride(Bi_(2)Te_(3)),as an emerging 2D material,has potential applications in electronic and spintronic devices due to its unique electrical properties.It is well known that the surface-to-volume ratio increases as the thickness of the material decreases,resulting in a more prominent edge effect.Therefore,for a single-layer Bi_(2)Te_(3),the atomic structure of the edge plays a crucial role in its electrical properties.Here,combining first-principles calculations and in situ transmission electron microscopy(TEM)experimental studies,we report that there are two types of edge structures in single-layer Bi2Te3:semiconducting flat edges and metallic zigzag edges.The dynamic evolution process of the edge structure with atomic resolution shows that the proportions of these two edges change with continuous electron beam irradiation.Our findings demonstrate the viability to use electron beam as an effective tool to precisely tailor the edge of Bi_(2)Te_(3) with desired properties,which paves the way for implementation of single-layer Bi2Te3 in electronics and spintronics.

Facile and secure synthesis of porous partially fluorinated graphene employing weakly coordinating anion for enhanced high-performance symmetric supercapacitor

In this paper,porous partially fluorinated graphene(PFG)for supercapacitors(SCs)was fabricated by a mild and secure one-pot hydrothermal method utilizing weakly coordinating anion BF_(4)^(-) as the fluorine source.The hydrolysis rate of sodium fluoroborate was adjusted by controlling the reaction temperature and PFG containing semi-ionic C-F bonds was obtained,where the content of semi-ionic C-F bonds in PFG can be easily regulated.The final experimental results show that the incorporation of fluorine not only modulates the electrochemical properties of the material,but also creates abundant pores.When assembled in a symmetric supercapacitor,the PFG shows a high specific capacitance of 269.7 F g^(-1) at 1 A g^(-1) and a superior rate capability with 89.3%capacitance retained,as the current density is increased from 1 A g^(-1)even to 20 A g^(-1).Furthermore,the resultant energy density for PFG is 9.4 Wh kg^(-1) at a power density of 250.0 W kg^(-1)(1 A g^(-1)).All these results confirm that as-prepared partially fluorinated graphene is appropriate for the application in SCs and mass production.