Construction of 3D porous Cu_(1.81)S/nitrogen-doped carbon frameworks for ultrafast and long-cycle life sodium-ion storage

Transition metal sulfides have great potential as anode mterials for sodium-ion batteries(SIBs)due to their high theoretical specific capacities.However,the inferior intrinsic conductivity and large volume variation during sodiation-desodiation processes seriously affect its high-rate and long-cyde performance,unbeneficial for the application as fast-charging and long-cycling SIBs anode.Herein,the three-dimensional porous Cu_(1.81)S/nitrogen-doped carbon frameworks(Cu_(1.81)S/NC)are synthesized by the simple and facile sol-gel and annealing processes,which can accommodate the volumetric expansion of Cu_(1.81)S nanoparticles and accelerate the transmission of ions and electrons during Na^(+)insertion/extraction processes,exhibiting the excellent rate capability(250.6 mA·g^(-1)at 20.0 A·g^(-1))and outstanding cycling stability(70% capacity retention for 6000 cycles at 10.0 A·g^(-1))for SIBs.Moreover,the Na-ion full cells coupled with Na_(3)V_(2)(PO_(4))_(3)/C cathode also demonstrate the satisfactory reversible specific capacity of 330.5 mAh·g^(-1)at 5.0 A·g^(-1)and long-cycle performance with the 86.9% capacity retention at 2.0 A·g^(-1)after 750 cycles.This work proposes a promising way for the conversionbased metal sulfides for the applications as fast-charging sodium-ion battery anode.

Role of transition metal oxides in g-C_(3)N_(4)-based heterojunctions for photocatalysis and supercapacitors

g-C_(3)N_(4) emerges as a star 2D photocatalyst due to its unique layered structure,suitable band structure and low cost.However,its photocatalytic application is limited by the fast charge recombination and low photoabsorption.Rationally designing g-C_(3)N_(4)-based heterojunction is promising for improving photocatalytic activity.Besides,g-C_(3)N_(4) exhibits great potentials in electrochemical energy storage.In view of the excellent performance of typical transition metal oxides(TMOs)in photocatalysis and energy storage,this review summarized the advances of TMOs/g-C_(3)N_(4) heterojunctions in the above two areas.Firstly,we introduce several typical TMOs based on their crystal structures and band structures.Then,we summarize different kinds of TMOs/g-C_(3)N_(4) heterojunctions,including type Ⅰ/Ⅱ heterojunction,Z-scheme,p-n junction and Schottky junction,with diverse photocatalytic applications(pollutant degradation,water splitting,CO_(2) reduction and N_(2) fixation)and supercapacitive energy storage.Finally,some promising strategies for improving the performance of TMOs/g-C_(3)N_(4) were proposed.Particularly,the exploration of photocatalysis-assisted supercapacitors was discussed.

ABCG2基因错义突变C21R与略阳乌鸡褐壳显著关联

蛋壳颜色变异是影响蛋品销售的一个重要因素。本研究以蛋壳色素原卟啉转运基因ABCG2为对象,旨在筛选出与鸡褐壳颜色变异关联的功能突变。选取381只31周龄的略阳乌鸡,每只母鸡收集3枚蛋,用L*a*b色度空间量化蛋壳颜色。用MassARRAY质谱法检测g.18378442T>C(错义突变C21R)、g.18383682A>G和g.18391548A>T的基因型,用单因素方差分析检验基因型与色度指标的关联性。在UCSC数据库调取52种鸟类物种的同源基因组序列,经序列比对,分析C21R位点的保守性。用MODELLER程序执行同源建模,分别构建C21和R21的蛋白3D结构,研究C21R对ABCG2蛋白结构的影响。结果表明,g.18378442T>C的CC基因型L值(75.3±4.0)显著低于CT(76.6±4.3)和TT(78.0±4.4),b值(16.2±3.5)显著高于CT(15.7±3.6)和TT型(14.7±3.2)。g.18383682A>G仅与L值显著关联。g.18391548A>T与3个色度指标的关联性均不显著。C21在45种鸟类物种中均完全保守,R21仅在两个鹦形目物种中出现。结构比对结果显示,C21R将引起468个结构改变,涉及氢键(49.6%)、溶剂可及性(38.8%)、正φ转角(8.1%)和二级结构(3.5%)变化。综上所述,C21R是一个与鸡褐壳颜色变异显著关联、对ABCG2结构有潜在影响的突变;其中,CC基因型与深褐壳关联,TT与浅褐壳关联。

High-performance asymmetrical supercapacitor composed of rGO-enveloped nickel phosphite hollow spheres and N/S co-doped rGO aerogel

An asymmetrical supercapacitor （ASC）, comprising reduced graphene oxide （rGO）-encapsulated nickel phosphite hollow microspheres （NPOH-0.5@rGO） as positive electrode, and porous nitrogen/sulfur co-doped rGO aerogel （NS-3D rGO） as negative electrode has been prepared. The NPOH-0.5@rGO electrode combines the advantages of the NPOH hollow microspheres and the conductive rGO layers giving rise to a large specific capacitance, high cycling reversibility, and excellent rate performance. The NS-3D rGO electrode with abundant porosity and active sites promotes electrolyte infiltration and broadens the working voltage range. The ASC （NPOH-0.5@rGO//NS-3D rGO） shows a maximum voltage of up to 1.4 V, outstanding cycling ability （capacitance retention of 95.5% after 10,000 cycles）, and excellent rate capability （capacitance retention of 77% as the current density is increased ten times）. The ASC can light up an light-emitting diodes （LED） for more than 20 min after charging for 20 s. The fabrication technique and device architecture can be extended to other active oxide and carbon-based materials for next-generation high-performance electrochemical storage devices.

Amorphous red phosphorus anchored on carbon nanotubes as high performance electrodes for lithium ion batteries

Red phosphorus-carbon nanotube （P@CNT） composites were synthesized as anodes for advanced lithium ion batteries via a facile solution-based method at room temperature. In these composites, the entangled P@CNT nanostructure reduced the aggregation of both components and allowed their complete utilization in a synergetic manner. The highly conductive and porous CNT framework, along with the nanoscale red P particles intimately anchored on the CNT surface, conferred the composite with excellent ion/electron transport properties. Volume expansion within the red P particles was mitigated by their amorphous and nanoscale features, which can be well buffered by the soft CNTs, therefore maintaining an integrated electrode structure during cycling. When used as an anode in lithium ion batteries, the composite exhibited a reversible capacity of 960 mAh·g^-1 （based on the overall weight of the composite） after 120 cycles at 200 mA·g^-1. The composite also delivered excellent high-rate capability with capacities of 886, 847, and 784 mAh·g^-1 at current densities of 2,000, 4,000, and 10,000 mA·g^-1 respectively, which reveals its potential as a high performance anode for lithium ion batteries.