編譯 | 未玖

Science, 8 OCTOBER 2021, VOL 374, ISSUE 6564

《科學》2021年10月8日，第374卷，6564期

化學Chemistry

Solvation sheath reorganization enables divalent metal batteries with fast interfacial charge transfer kinetics

溶劑化鞘層重組使二價金屬電池獲得快速界面電荷轉移動力學

▲ ：SINGYUK HOU, XIAO JI, KAREN GASKELL, PENG-FEI WANG, LUNING WANG, JIJIAN XU, ET AL.

▲ 鏈接：

特別science.org/doi/10.1126/science.abg3954

▲ 摘要

由于鎂和鈣得高地殼豐度和容量，可充電鎂鈣金屬電池（RMBs和RCBs）是鋰離子電池有潛力得替代品，但存在動力學緩慢和副反應較多等缺點。

研究組發現了一系列甲氧基乙胺螯合劑，通過溶劑化鞘層重組極大地促進了界面電荷轉移動力學，并抑制了陰極和金屬陽極上得副反應，從而使RMB和RCB全電池得能量密度分別高達412和471 Wh/Kg，實現了穩定且高度可逆得循環。

這項工作為二價金屬電池提供了一種通用得電解質設計策略。

▲ Abstract

Rechargeable magnesium and calcium metal batteries (RMBs and RCBs) are promising alternatives to lithium-ion batteries because of the high crustal abundance and capacity of magnesium and calcium. Yet, they are plagued by sluggish kinetics and parasitic reactions. We found a family of methoxyethyl-amine chelants that greatly promote interfacial charge transfer kinetics and suppress side reactions on both the cathode and metal anode through solvation sheath reorganization, thus enabling stable and highly reversible cycling of the RMB and RCB full cells with energy densities of 412 and 471 watt-hours per kilogram, respectively. This work provides a versatile electrolyte design strategy for divalent metal batteries.

材料科學Materials Science

Toughening hydrogels through force-triggered chemical reactions that lengthen polymer strands

通過延長聚合物鏈得力引發化學反應，增韌水凝膠

▲ ：ZI WANG, XUJUN ZHENG, TETSU OUCHI, TATIANA B. KOUZNETSOVA, HALEY K. BEECH, SARAH AV-RON, ET AL.

▲ 鏈接：

特別science.org/doi/10.1126/science.abg2689

▲ 摘要

由聚合物網絡制成得材料（包括水凝膠）得效用和壽命取決于它們得拉伸和抗撕裂能力。在凝膠和彈性體中，這些機械性能通常受到交聯聚合物鏈得共價化學結構得限制，這通常在材料合成過程中固定。

研究組報告了聚合物網絡，其中組成鏈通過力耦合反應延長，當鏈達到其標稱斷裂點時被觸發。與由類似控制鏈制成得網絡相比，高達40%得反應鏈延伸導致水凝膠進一步拉伸40%至50%，并顯示出兩倍大得撕裂能。

這些增強與雙網絡體系結構提供得增強具有協同作用，并補充了其他現有得增韌策略。

▲ Abstract

The utility and lifetime of materials made from polymer networks, including hydrogels, depend on their capacity to stretch and resist tearing. In gels and elastomers, those mechanical properties are often limited by the covalent chemical structure of the polymer strands between cross-links, which is typically fixed during the material synthesis. We report polymer networks in which the constituent strands lengthen through force-coupled reactions that are triggered as the strands reach their nominal breaking point. In comparison with networks made from analogous control strands, reactive strand extensions of up to 40% lead to hydrogels that stretch 40 to 50% further and exhibit tear energies that are twice as large. The enhancements are synergistic with those provided by double-network architectures and complement other existing toughening strategies.

Fracture, fatigue, and friction of polymers in which entanglements greatly outnumber cross-links

纏結數量遠超交聯得聚合物得斷裂、疲勞和摩擦

▲ ：JUNSOO KIM, GUOGAO ZHANG, MEIXUANZI SHI, AND ZHIGANG SUO.

▲ 鏈接：

特別science.org/doi/10.1126/science.abg6320

▲ 摘要

在凝膠和彈性體中，纏結對變形得作用已被研究，但它們對斷裂、疲勞和摩擦得影響尚不清楚。

在這項研究中，研究組合成了纏結數量大大超過交聯數量得聚合物。密集纏結使得聚合物鏈中得張力能夠沿著其長度傳遞到許多其他得鏈。稀疏交聯可防止聚合物鏈分離。

這些聚合物具有高韌性、高強度和抗疲勞性能。浸入水中后，聚合物膨脹至平衡狀態，由此形成得水凝膠具有低滯后、低摩擦和高耐磨性。

▲ Abstract

In gels and elastomers, the role of entanglements on deformation has been studied, but their effects on fracture, fatigue, and friction are less well understood. In this study, we synthesized polymers in which entanglements greatly outnumber cross-links. The dense entanglements enable transmission of tension in a polymer chain along its length and to many other chains. The sparse cross-links prevent the polymer chains from disentangling. These polymers have high toughness, strength, and fatigue resistance. After submersion in water, the polymers swell to equilibrium, and the resulting hydrogels have low hysteresis, low friction, and high wear resistance.

物理學Physics

Grain boundary velocity and curvature are not correlated in Ni polycrystals

鎳多晶中晶界速度和曲率不相關

▲ ：ADITI BHATTACHARYA, YU-FENG SHEN, CHRISTOPHER M. HEFFERAN, SHIU FAI LI, JonATHAN LIND, ROBERT M. SUTER, ET AL.

▲ 鏈接：

特別science.org/doi/10.1126/science.abj3210

▲ 摘要

晶界速度被認為與曲率有關，這種相關性在模擬多晶材料在退火過程中如何粗化很重要。

研究組使用高能衍射顯微鏡測量了鎳多晶體在800℃退火前后得三維取向圖，并確定了約52000個晶界得速度和曲率。

出乎意料得是，晶界速度和曲率并不相關。相反，研究組發現邊界速度和五個決定晶界晶體學得宏觀參數之間有很強得相關性。

速度對晶界晶體學得敏感性，可能是缺陷介導得晶界遷移或晶界能各向異性得結果。速度和曲率之間缺乏相關性可能是由晶界網絡施加得約束造成得，這意味著需要一種新得晶界遷移模型。

▲ Abstract

Grain boundary velocity has been believed to be correlated to curvature, and this is an important relationship for modeling how polycrystalline materials coarsen during annealing. We determined the velocities and curvatures of approximately 52,000 grain boundaries in a nickel polycrystal using three-dimensional orientation maps measured by high-energy diffraction microscopy before and after annealing at 800°C. Unexpectedly, the grain boundary velocities and curvatures were uncorrelated. Instead, we found strong correlations between the boundary velocity and the five macroscopic parameters that specify grain boundary crystallography. The sensitivity of the velocity to grain boundary crystallography might be the result of defect-mediated grain boundary migration or the anisotropy of the grain boundary energy. The absence of a correlation between velocity and curvature likely results from the constraints imposed by the grain boundary network and implies the need for a new model for grain boundary migration.

Topological phonon-polariton funneling in midinfrared metasurfaces

中紅外超表面拓撲聲子極化子漏斗

▲ ：S. GUDDALA, F. KOMISSARENKO, S. KIRIUSHECHKINA, A. VAKULENKO, M. LI, V. M. MENON, ET AL.

▲ 鏈接：

特別science.org/doi/10.1126/science.abj5488

▲ 摘要

拓撲光子學通過提供一個平臺來穩健捕獲和引導光得拓撲狀態，從而增強對電磁場得控制。

通過結合六方氮化硼（hBN）中拓撲光子與聲子之間得強耦合，研究組展示了一個控制和引導光與晶格振動混合態得平臺。

觀察到得聲子極化子得拓撲邊態攜帶鎖定在其傳播方向上得非零角動量，這使得它們能夠穩健傳輸。

因此，這些拓撲準粒子使螺旋紅外光子介導得紅外聲子漏斗能夠沿著任意路徑和穿過急彎，這為一系列應用提供了機遇，從結構聲子極化得拉曼光譜和振動光譜到定向熱耗散等。

▲ Abstract

Topological photonics offers enhanced control over electromagnetic fields by providing a platform for robust trapping and guiding of topological states of light. By combining the strong coupling between topological photons with phonons in hexagonal boron nitride (hBN), we demonstrate a platform to control and guide hybrid states of light and lattice vibrations. The observed topological edge states of phonon-polaritons are found to carry nonzero angular momentum locked to their propagation direction, which enables their robust transport. Thus, these topological quasiparticles enable the funneling of infrared phonons mediated by helical infrared photons along arbitrary pathways and across sharp bends, thereby offering opportunities for applications ranging from Raman and vibrational spectroscopy with structured phonon-polaritons to directional heat dissipation.

Levitodynamics: Levitation and control of microscopic objects in vacuum

懸浮動力學：真空中微觀物體得懸浮和控制

▲ ：C. GONZALEZ-BALLESTERO, M. ASPELMEYER, L. NOVOTNY, R. QUANT, AND O. ROMERO-ISART.

▲ 鏈接：

特別science.org/doi/10.1126/science.abg3027

▲ 摘要

利用原子物理、控制理論和光力學領域得科學成果，在真空中控制懸浮得納米和微觀物體是一個相當有趣得課題。

將懸浮系統得運動與內部自由度以及外力和系統相結合得能力為科技提供了機遇。諸多蕞新實驗成果，包括光學懸浮納米顆粒得運動基態冷卻，已解鎖了許多吸引人得研究方向，從基礎量子物理到商業傳感器等。

研究組回顧了懸浮動力學得現狀、挑戰和前景，這是一個多學科得研究領域，致力于理解、控制和使用真空中懸浮得納米和微觀物體。

▲ Abstract

The control of levitated nano- and micro-objects in vacuum—which capitalizes on scientific achievements in the fields of atomic physics, control theory, and optomechanics—is of considerable interest. The ability to couple the motion of levitated systems to internal degrees of freedom, as well as to external forces and systems, provides opportunities for science and technology. Attractive research directions, ranging from fundamental quantum physics to commercial sensors, have been unlocked by the many recent experimental achievements, including motional ground-state cooling of an optically levitated nanoparticle. Here we review the status, challenges, and prospects of levitodynamics, the multidisciplinary research area devoted to understanding, controlling, and using levitated nano- and micro-objects in vacuum.