Highly Branched VS4 Nanodendrites with 1D Atomic‐Chain Structure as a Promising Cathode Material for Long‐Cycling Magnesium Batteries

Rechargeable magnesium batteries have attracted increasing attention due to the high theoretical volumetric capacities, dendrite formation‐free characteristic and low cost of Mg metal anodes. However, the development of magnesium batteries is seriously hindered by the lack of capable cathode materials with long cycling life and fast solid‐state diffusion kinetics for highly‐polarized divalent Mg²⁺ ions. Herein, vanadium tetrasulfide (VS₄) with special one‐dimensional atomic‐chain structure is reported to be able to serve as a favorable cathode material for high‐performance magnesium batteries. Through a surfactant‐assisted solution‐phase process, sea‐urchin‐like VS₄ nanodendrites are controllably prepared. Benefiting from the chain‐like crystalline structure of VS₄, the S₂^2‐ dimers in the VS₄ nanodendrites provide abundant sites for Mg²⁺ insertion. Moreover, the VS₄ atomic‐chains bonded by weak van der Waals forces are beneficial to the diffusion kinetics of Mg²⁺ ions inside the open channels of VS₄. Through a series of systematic ex situ characterizations and density functional theory calculations, the magnesiation/demagnesiation mechanism of VS₄ are elucidated. The VS₄ nanodendrites present remarkable performance for Mg²⁺ storage among existing cathode materials, exhibiting a remarkable initial discharge capacity of 251 mAh g^‐1 at 100 mA g^‐1 and an impressive long‐term cyclability at large current density of 500 mA g^‐1 (74 mAh g^‐1 after 800 cycles).     

Template-Sacrificed Hot Fusion Construction and Nanoseed Modification of 3D Porous Copper Nanoscaffold Host for Stable-Cycling Lithium Metal Anodes

Lithium (Li) metal anodes have been proposed as a promising candidate for high-energy-density electrode materials in secondary batteries. However, the dendrite growth and unstable electrode–electrolyte interfaces during Li plating/stripping are fatal to their practical applications. Herein, the construction of 3D porous Au/Cu nanoscaffold prepared via a convenient template-sacrificed hot fusion construction method and a nanoseed modification process as an effective Li metal hosting material are proposed. The Au/Cu nanoscaffold can spatially guide uniform deposition of Li metal free from the growth of Li dendrites due to the homogenous Li⁺ ion flux and negligible nucleation overpotential. Moreover, the Cu skeleton can relieve volume change and stabilize local current density during cycling processes. Benefiting from these advantages, the symmetric cells based on self-supported Li-filled Au/Cu (Li-Au/Cu) nanoscaffold electrodes present highly stable Li plating/stripping for more than 1000 h with a low voltage hysteresis less than 90 mV and a long lifespan over 1300 h at 1.0 mA cm^–2 in carbonate-based electrolytes. Impressively, the Li-Au/Cu nanoscaffold||LiFePO₄ full cells also exhibit exceptional cycling stability and rate performance. This work provides a promising strategy to construct dendrite-free lithium metal anodes toward high-performance lithium metal batteries.     

大力发展"第三代"光伏发电技术,应对"碳减排"的挑战

当前的光伏产业正由基于晶体硅的"第一代"技术,向使用薄膜的"第二代"技术转变.然而,"第三代"技术在近期由于"4倍聚光+跟踪+太阳能炼硅+晶体硅+薄膜"的结合而成为现实.基于这一技术的电价可降至0.4～0.5元/kWh.     

基于响应面法的汽车接插件翘曲变形优化

为减少汽车接插件在注塑成型过程中出现翘曲变形问题,以某汽车接插件为研究对象,选取模具温度、熔体温度和保压压力为响应面影响因素,以塑件的翘曲变形值为响应目标,运用响应面法Box-Behnken设计试验方案. 利用Design-Expert软件分析试验结果,建立响应面响因素与响应值之间的二阶响应面模型,获得最佳工艺参数组合为:模具温度为50 ℃、熔体温度为280 ℃、保压压力为60 MPa. 试验结果表明,采用该工艺组合生产的注塑件翘曲变形值下降21.26%,符合预期要求.     

In Situ Structure Refactoring of Bismuth Nanoflowers for Highly Selective Electrochemical Reduction of CO2 to Formate

The electrocatalytic CO₂ reduction reaction (CO₂RR) has been considered a promising route toward carbon neutrality and renewable energy conversion. At present, most bismuth (Bi) based electrocatalysts are adopted to reduce CO₂ to formate (HCOOH). However, the mechanism of different Bi nanostructures on the electrocatalytic performance requires more detailed exposition. Herein, a combined chemical replacement and electrochemical reduction process is reported to realize in situ morphology reconstruction from Bi@Bi₂O₃ nanodendrites (Bi@Bi₂O₃-NDs) to Bi nanoflowers (Bi-NFs). The Bi@Bi₂O₃-NDs are proven to undergo a two-step transformation process to form Bi-NFs, aided by Bi₂O₂CO₃ as the intermediate in KHCO₃ solution. Extensive surface reconstruction of Bi@Bi₂O₃-NDs renders the realization of tailored Bi-NFs electrocatalyst that maximize the number of exposed active sites and active component (Bi⁰), which is conducive to the adsorption and activation of CO₂ and accelerated electron transfer process. The as-prepared Bi-NFs exhibit a Faradaic efficiency (FE_formate) of 92.3% at −0.9 V versus RHE and a high partial current density of 28.5 mA cm⁻² at −1.05 V versus RHE for the electroreduction of CO₂ to HCOOH. Moreover, the reaction mechanism is comprehensively investigated by in situ Raman analysis, which confirms that *OCHO is a key intermediate for the formation of HCOOH.     

Three-dimensional spongy framework as superlyophilic,strongly absorbing,and electrocatalytic polysulfide reservoir layer for high-rate and long-cycling lithium-sulfur batteries

Nano Research - In the development of lithium-sulfur (Li-S) batteries, various approaches have been adopted to enhance the electronic conductivity of the sulfur cathode and alleviate the shuttle...     

测量磁单极子通量的天然白云母的裂变径迹年龄测定

当自然界中的磁单极子穿过地壳时,磁单极子—原子核结合体在云母中形成径迹。选用新疆白云母作为探测器,测得云母的裂变径迹年龄为(129±8)×10~6a,可以认为白云母的裂变径迹年龄即为它记录磁单极子—原子核结合体径迹年龄的近似值。     

彻底解决我国未来能源问题是依靠核能,还是依靠可再生能源?

彻底解决我国未来能源问题是依靠核能,还是依靠可再生能源?目前在世界范围内出现的事实是:2002年全世界消费的可再生能源为19.66亿t标准煤,约相当于     

Versatile Electronic Skins for Motion Detection of Joints Enabled by Aligned Few‐Walled Carbon Nanotubes in Flexible Polymer Composites

Here, novel multifunctional electronic skins (E‐skins) based on aligned few‐walled carbon nanotube (AFWCNT) polymer composites with a piezoresistive functioning mechanism different from the mostly investigated theory of “tunneling current channels” in randomly dispersed CNT polymer composites are demonstrated. The high performances of as‐prepared E‐skins originate from the anisotropic conductivity of AFWCNT array embedded in flexible composite and the distinct variation of “tube‐to‐tube” interfacial resistance responsive to bending or stretching. The polymer/AFWCNT‐based flexion‐sensitive E‐skins exhibit high precision and linearity, together with low power consumption (<10 µW) and good stability (no degradation after 15 000 bending–unbending cycles). Moreover, polymer/AFWCNT composites can also be used for the construction of tensile‐sensitive E‐skins, which exhibit high sensitivity toward tensile force. The polymer/AFWCNT‐based E‐skins show remarkable performances when applied to monitor the motions and postures of body joints (such as fingers), a capability that can find wide applications in wearable human–machine communication interfaces, portable motion detectors, and bionic robots.     

Fluorinated Interface Engineering toward Controllable Zinc Deposition and Rapid Cation Migration of Aqueous Zn-Ion Batteries

Metallic zinc (Zn) is a highly promising anode material for aqueous energy storage systems due to its low redox potential, high theoretical capacity, and low cost. However, rampant dendrites/by-products and torpid Zn²⁺ transfer kinetics at electrode/electrolyte interface severely threaten the cycling stability, which deteriorate the electrochemical performance of Zn-ion batteries. Herein, an interfacial engineering strategy to construct alkaline earth fluoride modified metal Zn electrodes with long lifespan and high capacity retention is reported. The compact fluoride layer is revealed to guide uniform Zn stripping/plating and accelerate the transfer/diffusion of Zn²⁺ via Maxwell-Wagner polarization. A series of in situ and ex situ spectroscopic studies verified that the fluoride layer can guide uniform Zn stripping/plating. Electrochemical kinetics analyses reveal that positive effect on the removal of Zn²⁺ solvation sheath provided by fluoride layer. Meanwhile, this fluoride coating layer can act as a barrier between the Zn electrode and electrolyte, providing a high electrode overpotential toward hydrogen evolution reaction to hold back H₂ evolution. Consequently, the fluoride-modified Zn anode exhibited a capacity retention of 88.2% after 4000 cycles under10 A g⁻¹. This work opens up a new path to interface engineering for propelling the exploration of advanced rechargeable aqueous Zn-ion batteries.