Ultrathin and Ultralight Zn Micromesh-Induced Spatial-Selection Deposition for Flexible High-Specific-Energy Zn-Ion Batteries

Ultraflexible and ultralight rechargeable aqueous Zn-ion batteries (ZIBs) with the merits of environmental benignity and high security arise as promising candidates for flexible electronic systems. Nowadays, the energy density and cyclical stability of ZIBs on metal-based rigid substrates reach a satisfactory level, while the inflexible substrates severely prevent them from widespread commercial adoption in portable electronics. Although flexible substrates-engineered devices burgeon, the development of flexible ZIBs with high specific energy still faces great challenges. Herein, a flexible ultrathin and ultralight Zn micromesh (thickness of 8 µm and areal density of 4.9 mg cm⁻²) with regularly aligned microholes is fabricated via combining photolithography with electrochemical machining. The unique microholes-engineered Zn micromesh presents excellent flexibility, enhanced mechanical strength, and better wettability. Moreover, numerical simulations in COMSOL and in situ microscopic observation system certify the induced spatial-selection deposition of Zn micromesh. Accordingly, aqueous ZIBs constructed with polyaniline-intercalated vanadium oxide cathode and Zn micromesh anode demonstrate exceptional high-rate capability (67.6% retention with 100 times current density expansion) and cyclical stability (maintaining 87.6% after 1000 cycles at 10.0 A g⁻¹). Furthermore, the assembled pouch cell displays superb flexibility and durability under different scenarios, indicating great prospects in high-energy ZIBs and flexible electronics.     

Multiscale Ion-Sieving Separator with Selective Zn2+ Channels and Excellent Zn2+ Desolvation Kinetics for Dendrite-Free and Kinetics-Enhanced Zinc Metal Batteries

Zn metal batteries have garnered considerable scientific and technological interests. However, the widespread commercial application of these batteries is impeded by the uncontrollable dendrite growth and consequent severe side effects. Herein, a functionalized separator is prepared by spraying polyaniline-modified graphene oxide (denoted as NPGO)/polyvinylidene difluoride solution directly on one side of a common separator of glass fibers (GFs). The reversible transition between protonated and deprotonated states of quinolone imide on NPGO nanosheets can facilitate the rapid desolvation and transfer of Zn²⁺. Therefore, the spatial electric field as well as the Zn²⁺ flux is effectively homogenized due to the ion-sieving effect of NPGO nanosheets that are oriented toward Zn anode. This engineering design of the NPGO@GFs separator harvests excellent rate and cycling performance (over 3000 cycles at 20 mA cm⁻²) for Zn metal symmetric batteries. Meanwhile, it provides an impressive commercial prospect (500 cycles with a capacity retention of 91.6% under 2000 mA g⁻¹) for MnO₂||Zn full batteries. Such a strategy can be generalized as a common way to protect metal anodes (Na, Zn, and K) in rechargeable batteries, which is highly cost-effective and scalable.     

间隔0.256 nm的多波长布里渊光纤激光器的实验研究

使用一个四端口环行器和两个三端口环形器,设计了一种波长间隔为0.256 nm的多波长布里渊掺铒光纤激光器。该激光器中使用的两个三端口环行器组成的环腔产生一阶Stokes光,四端口环行器组成的环腔产生与入射进腔内的BP光相隔双倍布里渊频移的Stokes光。实验测试得到:当BP为3 dBm、980 nm泵浦功率为27.78 dBm时,可得到波长间隔为0.256 nm的6个波长的激光输出,同时也讨论了Stokes光的数量与BP光功率和980 nm泵浦光功率之间的变化关系。     

Engineering the Interlayer Spacing by Pre-Intercalation for High Performance Supercapacitor MXene Electrodes in Room Temperature Ionic Liquid

MXenes exhibit excellent capacitance at high scan rates in sulfuric acid aqueous electrolytes, but the narrow potential window of aqueous electrolytes limits the energy density. Organic electrolytes and room-temperature ionic liquids (RTILs) can provide higher potential windows, leading to higher energy density. The large cation size of RTIL hinders its intercalation in-between the layers of MXene limiting the specific capacitance in comparison to aqueous electrolytes. In this work, different chain lengths alkylammonium (AA) cations are intercalated into Ti₃C₂T_x, producing variation of MXene interlayer spacings (d-spacing). AA-cation-intercalated Ti₃C₂T_x (AA-Ti₃C₂), exhibits higher specific capacitances, and cycling stabilities than pristine Ti₃C₂T_x in 1 m 1-ethly-3-methylimidazolium bis-(trifluoromethylsulfonyl)-imide (EMIMTFSI) in acetonitrile and neat EMIMTFSI RTIL electrolytes. Pre-intercalated MXene with an interlayer spacing of ≈2.2 nm, can deliver a large specific capacitance of 257 F g⁻¹ (1428 mF cm⁻² and 492 F cm⁻³) in neat EMIMTFSI electrolyte leading to high energy density. Quasi elastic neutron scattering and electrochemical impedance spectroscopy are used to study the dynamics of confined RTIL in pre-intercalated MXene. Molecular dynamics simulations suggest significant differences in the structures of RTIL ions and AA cations inside the Ti₃C₂T_x interlayer, providing insights into the differences in the observed electrochemical behavior.     

Durable Integrated K-Metal Anode with Enhanced Mass Transport through Potassiphilic Porous Interconnected Mediator

K-metal batteries have become one of the promising candidates for the large-scale energy storage owing to the virtually inexhaustible and widely potassium resources. The uneven K⁺ deposition and dendrite growth on the anode causes the batteries prematurely failure to limit the further application. An integrated K-metal anode is constructed by cold-rolling K metal with a potassiphilic porous interconnected mediator. Based on the experimental results and theoretical calculations, it demonstrates that the potassiphilic porous interconnected mediator boosts the mass transportation of K-metal anode by the K affinity enhancement, which decreases the concentration polarization and makes a dendrite-free K-metal anode interface. The interconnected porous structure mitigates the internal stress generated during repetitive deposition/stripping, enabling minimized the generation of electrode collapse. As a result, a durable K-metal anode with excellent cycling ability of exceed 1, 000 h at 1 mA cm⁻²/1 mAh cm⁻² and lower polarization voltage in carbonate electrolyte is obtained. This proposed integrated anode with fast K⁺ kinetics fabricated by a repeated cold rolling and folding process provides a new avenue for constructing a high-performance dendrites-free anode for K-metal batteries.     

表面等离子阵列结构中的耦合增强反射效应其红外光谱增强特性研究

使用聚焦离子束刻蚀的方法制备了不同间距的表面等离子结构阵列,研究了由方形和圆形所构成的阵列在不同间距下的光学反应.实验表明,粒子之间耦合效应随着间距的显著减小而逐渐变强,从弱耦合变化为强耦合状态.当间距小于30 nm时,发现耦合增强的反射效应,共振波长也会随着间距的减小而发生红移.将制备的超小间距纳米阵列和傅里叶变换光谱仪的ATR附件相耦合,实验验证了相关阵列结构在红外光谱增强方面的显著效果.相关的发现和表面等离子阵列结构可以在传感、探测和光谱增强等方面取得一定的应用.     

分集MIMO 雷达布站研究

分集多输入多输出(MIMO)雷达利用目标的空间散射多样性克服由于目标雷达散射截面积闪烁引起的漏警,为隐身目标有效探测提供解决办法。分集MIMO 雷达布站方式对性能影响很大,文中以相控阵体制雷达为研究对象,研究其组成分集MIMO 雷达时的规模、站间距、单站威力差异约束和布站方式等,并通过蒙特卡罗仿真给出了布站建议。     

Toward High‐Performance Hybrid Zn‐Based Batteries via Deeply Understanding Their Mechanism and Using Electrolyte Additive

Aqueous hybrid Zn‐based batteries (ZIBs), as a highly promising alternative to lithium‐ion batteries for grid application, have made considerable progress recently. However, few studies have been reported that investigate their working mechanism in detail. Here, the operando synchrotron X‐ray diffraction is employed to thoroughly investigate the operational mechanism of a hybrid LiFePO₄(LFP)/Zn battery, which indicates only Li⁺ extraction/insertion from/into cathode during cycling. Based on this system, a cheap electrolyte additive, sodium dodecyl benzene sulfonate, is proposed to effectively enhance its electrochemical properties. The influence of the additive on the Zn anode and LFP cathode is comprehensively studied, respectively. The results show that the additive modifies the intrinsic deposit pattern of Zn²⁺ ions, rendering Zn plating/stripping highly reversible in an aqueous medium. On the other hand, the wettability of the LFP electrode is visibly a meliorated by introducing the surfactant additive, accelerating the Li‐ion diffusion at the LFP electrode/electrolyte interface, as indicated by the overpotential measurements. Benefiting from these effects, the Zn/LFP batteries deliver high rate capability and cycling stability in both coin cells and pouch cells.     

检测散射元间距的多分辨率分析方法

本文研究了从生物组织的背向散射信号中提取散射元间距信息的多分辨率分析方法。从文中构造一维生物组织超声散射模型可以看到,散射元间距信息隐含在背向散射信号的低频包络中。本文采用绝对值检波方法作多分辨率分析的预处理,并采用能量最大准则确定检测的敏感尺度。仿真试验结果表明,这种方法可以有效地提取出背向散射信号中低频包络信息,准确地检测出散射元的位置;具有较强的抗噪性。