Electric-field-induced second harmonic generation (EFISH), an intriguing third-order nonlinear process, not only breaks the limitation of second-order susceptibilities to strengthen the second harmonic (SH) intensity but also imparts metasurfaces with tunability, making them more adaptable and effective in diverse applications. However, attaining a robust nonlinear modulation with EFISH remains a challenge due to the intrinsically weak interactions. In this work, a tunable lithium niobate (LiNbO 3 ) metasurface based on a multi-mode Fano mechanism, dubbed Super Fano, is proposed and investigated. Combining the giant confined field and excellent material properties of LiNbO 3 , both SHG conversion and its nonlinear modulation efficiency are boosted. Our LiNbO 3 achieves an EFISH modulation depth of ∼900% per volt. As demonstrated, a nonlinear optical switch with an on-off ratio of ∼ 29 is attained. The Super-Fano-enhanced EFISH metasurface opens up new avenues for the design and construction of on-chip nonlinear optical devices.

AbstractUnlike bulky and rigid traditional power systems, 1D fiber batteries possess appealing features such as flexibility and adaptability, which are promising for use in wearable electronic devices. However, the performance and energy density fiber batteries are limited by the contradiction between ionic transfer and robust structure of fiber electrodes. Herein, these problems are addressed via polymer engineering to regulate the microenvironment in electrodes, realizing high‐linear‐capacity thick fiber electrodes with excellent cycling performance. The porosity of the electrodes is regulated using polymer crosslink networks designed with various components, and lithium‐ion transfer is optimized through ether‐abundant polymer chains. Furthermore, reinforced covalent bonding with carbon nanotube networks is established based on the modified functional groups of polymer networks. The multiscale optimizations of the porous structure, ionic transportation, and covalent bonding network enhance the lithium‐ion dynamics property and structural stability. Therefore, ultrahigh linear‐capacity fiber electrodes (17.8 mAh m−1) can be fabricated on a large scale and exhibit excellent stability (92.8% after 800 cycles), demonstrating obvious superiority among the reported fiber electrodes. Moreover, this study highlights the high effectiveness of polymer regulation in fiber electrodes and offers new avenues for designing next‐generation wearable energy‐storage systems.

锂离子电池高还原性负极表面的固体电解质界面膜(SEI)是影响电池电化学性能与稳定性的关键组分,但SEI的形成涉及多尺度、多物理场下的复杂过程,且组分异常复杂.在电池外壳"黑箱"环境下,现有的非原位技术对其表征无能为力,而原位技术又难以得到较高真实度的结果,难以深入理解SEI的相关机制.采用数学的方法对SEI进行建模研究,有望将复杂的物理场进行解耦,进而精准描述SEI的形成和演化的机制与过程,是近年来电池领域的研究热点.本文按对象尺度由小到大从原子到介观尺度逐渐增大的顺序分别总结了第一性原理分子动力学、反应力场分子动力学、经典分子动力学、蒙特卡罗算法、宏观性质建模在SEI建模研究中的应用进展,介绍其在指导电极材料开发及电解液改性方面的成功案例,着重讨论分析了多尺度建模研究SEI的难点与不足.并提出针对SEI的电化学势场特性建立力场算法平台,采用动力学蒙特卡罗方法和机器学习辅助将模型拓展到数万直至数亿原子,并通过逐级计算结合试验验证及专家评估促使收敛,获得具有量子力学精度且带电化学势场的SEI模型,有望实现SEI的长时域建模.

The growing demand for wearable electronics has boosted research on flexible fiber batteries. 3D printing has been applied to fiber battery manufacturing, in which tremendous amount of polymer binders with low conductivity are required. Replacing polymer by conducting skeleton such as graphene can offer long-range conductivity and high active material ratio. However, poor interaction and vast voids between active materials and skeletons result in fragile structure with inferior stabilities. Herein, a facile in-situ interface reinforcement method is proposed to print stable binder-free fiber electrodes. Electrode inks consisting of common LiFePO4 (LFP) particles and graphene oxide (GO) are directly printed in a solution containing dopamine and calcium ions. Catalyzed by Ca2+, dopamine that permeated into the fiber could rapidly polymerize and synchronously establish crosslinks during printing. Subsequently, polydopamine-derived carbon (PDC) networks efficiently reinforce the interface. The PDC at interfaces enriches the electron-transfer pathways and ensures a tight connection through covalent and 7C-7C bonding. The reinforcement enables the printed binder-free electrodes to possess remarkably higher stability, flexibility, and durability under deformation. Additionally, the proposed method has remarkable application potential both for individual fiber batteries and directly printed battery textiles, thereby enabling new possibilities for future wearable energy-storage fabrics.

Lithium ion batteries (LIBs) have swept the whole energy storage field. However, the current mainstream lithium batteries are difficult to operate stably at high temperature (> 60?) due to the decomposition of electrolyte and solid electrolyte interphase (SEI), the cathode metal elements dissolution behavior, and potential thermal runaway. Here, We report a double-salt electrolyte with lithium bis(fluorosulfonyl)imide (LiFSI) and lithium difluoro(oxalato)borate (LiDFOB) as electrolyte salt, fluoroethylene carbonate (FEC), and tetra(ethylene glycol) dimethyl ether (TEGDME) as cosolvent, which delivers excellent ionic conductivity, high electrochemical stability and satisfactory ability to impede the dissolution of Fe element under elevated temperature (70?). In addition, the electrolyte is benefited to form a robust and thermal-resistance solid-electrolyte interface (SEI) layer on the surface of graphite (Gr) anode, which shows improved decomposition temperature (86?). The assembled thermally stable and high-safety 1300 mAh 18650-type LiFePO4|Gr cell shows high Coulombic efficiency (~99.7%), improved cycling stability with discharge capacity 871.1 mAh after 200 cycles at 0.5 C and 70?. This work affords a splendid strategy for address the unstable interface at both cathode and anode for safe high-temperature LIBs.

Garnet Li7La3Zr2O12 (LLZO) has been a prospective solid electrolyte with high ionic conductivity and a wide electrochemical window. Different from conventional cold or hot isostatic pressing methods, a self-consolidation strategy without any pressing assistance was proposed to prepare dense LLZO. In this work, simultaneous substitution of Nb2O5 and Ta2O5 was attempted to further explore the mechanism of self-consolidation sintering. The influence of the Nb2O5 and Ta2O5 substitution amount on the crystalline phase, morphology, and ionic conductivity was investigated. Due to the different melting points and thermal behaviors of Nb2O5 and Ta2O5, the endothermic peak corresponding to sintering became weaker, which was associated with the self-consolidation process of LLZO. Accordingly, larger grain sizes and fewer grain boundaries were observed in LLZO when the amounts of Nb2O5 and Ta2O5 were both 0.25 mol. This indicates that the simultaneous substitution of different cations plays a vital role in selfconsolidation sintering, which contributes to facilitating the grain growth and reducing the amount of grain boundaries. This work emphasizes the key role of the dopant melting point and thermal behavior in sintering, suggesting an alternative way of substitution for LLZO electrolyte preparation.

Rapid development of portable or wearable devices, which is inspired by requirements of instant messaging, health monitoring and handling official business, urgently demands more tiny, flexible and light power sources. Fiber-shaped batteries explored in recent years become a prospective candidate to satisfy these demands. With 1D architecture, the fiber-shaped batteries could be adapted to various deformations and integrated into soft textile and other devices. Numerous researches have been reported and achieved huge promotion. To give an overview of fiber-shaped batteries, we summarized the development of fiber-shaped batteries in this review, and discussed the structure and materials in fiber-shaped batteries. The flexibility of batteries with the potential application of the batteries was also exhibited and showed the future perspective. Finally, challenges in this field were discussed, hoping to reveal research direction towards further development of fiber-shaped batteries.

Garnet Li7La3Zr2O12 (LLZO) is a potential solid electrolyte for solid-state batteries (SSBs) because of its high ionic conductivity, electrochemical stability, and mechanical strength. However, large interface resistances arising from deserted cathodes and rigid garnet/electrode interfaces block its application. In order to deal with this issue, a gel polymer electrolyte (GPE) was introduced into the cathode and both sides of LLZO to achieve a solid-state battery. Especially, the provided GPE could be thermally polymerized and solidified in situ, which would integrate LLZO with both anode and cathode and dramatically simplify the battery manufacturing process. Since the interface from rigid LLZO is improved by the flexible GPE buffer, the inability of flexible GPE to inhibit lithium dendrites is compensated by the rigid LLZO in return. As a result, the interface resistances are reduced from 6880 to 473 Ω, the Li symmetric cell exhibits a flat galvanostatic charge/discharge for 400 h without lithium dendrites, and the solid-state Li|GPE@LLZO|LiCoO2 battery exerts a capacity retention of 82.6% after 100 cycles at 0.5 C at room temperature. Such an interfacial engineering approach represents a promising strategy to address solid-solid interface issues and provides a new design for SSBs with high performance.

A novel method to fabricate flexible free-standing electrodes with textile structure for lithium-ion batteries was provided by applying extrusion-based three-dimensional (3D) printing technology.Meanwhile,highly concentrated poly(vinylidene fluoride) (PVDF) is used as viscosity modifier,carbon nanotube (CNT) as conducting additive,and lithium iron phosphate (LFP) or lithium titanium oxide (LTO) as cathode or anode active materials respectively to develop printable inks with obvious shear-thinning behavior,and with the apparent viscosity and storage modulus platform value of over 105Pa · s,which is beneficial to the printability and enable complex 3D structures solidification.The electrochemical test shows that both printed electrodes have similar charge and discharge specific capacities under current density of 50mA · g-1.To explore the feasibility of the printed electrodes,a pouch cell with as-printed LFP and LTO electrode as cathode and anode respectively is assembled.The pouch cell without deformation delivers discharge specific capacities of approximately 108mAh · g-1,and there is a tiny increase in discharge specific capacities of around 111 mAh · g-1 for bended pouch cell.

Conventional bulky and rigid power systems are incapable of meeting flexibility and breathability requirements for wearable applications. Despite the tremendous efforts dedicated to developing various 1D energy storage devices with sufficient flexibility, challenges remain pertaining to fabrication scalability, cost, and efficiency. Here, a scalable, low-cost, and high-efficiency 3D printing technology is applied to fabricate a flexible all-fiber lithium-ion battery (LIB). Highly viscous polymer inks containing carbon nanotubes and either lithium iron phosphate (LFP) or lithium titanium oxide (LTO) are used to print LFP fiber cathodes and LTO fiber anodes, respectively. Both fiber electrodes demonstrate good flexibility and high electrochemical performance in half-cell configurations. All-fiber LIB can be successfully assembled by twisting the as-printed LFP and LTO fibers together with gel polymer as the quasi-solid electrolyte. The all-fiber device exhibits a high specific capacity of approximate to 110 mAh g(-1) at a current density of 50 mA g(-1) and maintains a good flexibility of the fiber electrodes, which can be potentially integrated into textile fabrics for future wearable electronic applications.

A novel method to fabricate low tortuosity (as low as 1),ultra-thick hierarchical porous electrode for lithium-ion battery by the extrusion-based three-dimensional (3D) printing technology is presented.Meanwhile,the printable ink is formulated by using the graphene oxide (GO) with a concentration of 80 mg·mL-1 as viscosity modifier and lithium iron phosphate as electrode active material.The ink has an apparent viscosity as high as 104 Pa · s,and exhibits obvious shear-thinning behavior.It is noted that the ink's storage modulus plateau is as high as 104 Pa· s.These excellent rheological properties are very useful for the printing and curing processes,which ensure precision and integrity of printing structure.It is demonstrated via the electrochemical test that this electrode's initial voltage difference between the charge and discharge plateaus is around 0.12 V,only one third that of the traditional coated electrodes with uniform active materials loading mass of 21 mg · cm-2.Also,the rate performance of this 3D printed electrode is improved substantially,and its charge transfer resistance can decrease to one fifty that of traditional electrode.

Highly conductive and mechanically strong microfibers are attractive in energy storage, thermal management, and wearable electronics. Here, a highly conductive and strong carbon nanotube/nanofibrillated cellulose (CNT-NFC) composite microfiber is developed via a fast and scalable 3D-printing method. CNTs are successfully dispersed in an aqueous solution using 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO) oxidated NFCs, resulting in a mixture solution with an obvious shear-thinning property. Both NFC and CNT fibers inside the all-fiber-based microfibers are well aligned, which helps to improve the interaction and percolation between these two building blocks, leading to a combination of high mechanical strength (247 +/- 5 MPa) and electrical conductivity (216.7 +/- 10 S cm(-1)). Molecular modeling is applied to offer further insights into the role of CNT-NFC fiber alignment for the excellent mechanical strength. The combination of high electrical conductivity, mechanical strength, and the fast yet scalable 3D-printing technology positions the CNT-NFC composite microfiber as a promising candidate for wearable electronic devices.

Transient electronics is an emerging engineering realm that requires materials, devices, and systematic designs with excellent and stable performance in regular operations, but to physically and chemically disappear at a prescribed time with controlled rates once being triggered by external stimulus, leaving no or minimum remnants. In this article, a high energy density rechargeable battery with a fully transient cathode based on tin (Sn)‐doped vanadium oxide (V 2 O 5 ) is designed. Sn‐doped V 2 O 5 nanofibers with a high mass loading of 12 mg cm −2 are prepared and no conducting additive or binder is added to fabricate full cells. The transient battery exhibits an areal capacity of 2 mAh cm −2 with a working voltage above 2.0 V and provides 0.27 mAh cm −2 capacity at a current as high as 17.76 mA cm −2 . Once triggered by potassium hydroxide (KOH) aqueous solution, the full cell can be completely dissolved into the solution within a few minutes to achieve highly transient capability. This work provides a new approach to achieve an all‐transient lithium battery with high areal capacity for transient electronics applications.

Nanoparticles hosted in conductive matrices are ubiquitous in electrochemical energy storage, catalysis and energetic devices. However, agglomeration and surface oxidation remain as two major challenges towards their ultimate utility, especially for highly reactive materials. Here we report uniformly distributed nanoparticles with diameters around 10 nm can be self-assembled within a reduced graphene oxide matrix in 10 ms. Microsized particles in reduced graphene oxide are Joule heated to high temperature (∼1,700 K) and rapidly quenched to preserve the resultant nano-architecture. A possible formation mechanism is that microsized particles melt under high temperature, are separated by defects in reduced graphene oxide and self-assemble into nanoparticles on cooling. The ultra-fast manufacturing approach can be applied to a wide range of materials, including aluminium, silicon, tin and so on. One unique application of this technique is the stabilization of aluminium nanoparticles in reduced graphene oxide film, which we demonstrate to have excellent performance as a switchable energetic material.

Highly efficient broadband thermal radiation from reduced graphene oxide (RGO) paper mixed with single-walled carbon nanotubes (CNTs) is reported. These RGO-CNT paper ribbons routinely reach 3000 K before failure, with some samples exceeding 3300 K, higher than any other carbon nanomaterial. Excellent performance is achieved, with ≈90% radiation efficiency, 200 000 on/off cycles, and stable operation for more than 50 hours.

Advanced Energy MaterialsVolume 6, Issue 10 1502496 Communication All-Component Transient Lithium-Ion Batteries Kun (Kelvin) Fu, Kun (Kelvin) Fu Department of Materials Science and Engineering, University of Maryland College Park, College Park, MD, 20742 USASearch for more papers by this authorZhengyang Wang, Zhengyang Wang Department of Materials Science and Engineering, University of Maryland College Park, College Park, MD, 20742 USASearch for more papers by this authorChaoyi Yan, Chaoyi Yan Department of Materials Science and Engineering, University of Maryland College Park, College Park, MD, 20742 USASearch for more papers by this authorZhen Liu, Zhen Liu Department of Materials Science and Engineering, University of Maryland College Park, College Park, MD, 20742 USASearch for more papers by this authorYonggang Yao, Yonggang Yao Department of Materials Science and Engineering, University of Maryland College Park, College Park, MD, 20742 USASearch for more papers by this authorJiaqi Dai, Jiaqi Dai Department of Materials Science and Engineering, University of Maryland College Park, College Park, MD, 20742 USASearch for more papers by this authorEmily Hitz, Emily Hitz Department of Materials Science and Engineering, University of Maryland College Park, College Park, MD, 20742 USASearch for more papers by this authorYibo Wang, Yibo Wang Department of Materials Science and Engineering, University of Maryland College Park, College Park, MD, 20742 USASearch for more papers by this authorWei Luo, Wei Luo Department of Materials Science and Engineering, University of Maryland College Park, College Park, MD, 20742 USASearch for more papers by this authorYanan Chen, Yanan Chen Department of Materials Science and Engineering, University of Maryland College Park, College Park, MD, 20742 USASearch for more papers by this authorMyeongseob Kim, Myeongseob Kim BAE Systems, Columbia, MD, 21046 USASearch for more papers by this authorLiangbing Hu, Corresponding Author Liangbing Hu Department of Materials Science and Engineering, University of Maryland College Park, College Park, MD, 20742 USAE-mail: binghu@umd.eduSearch for more papers by this author Kun (Kelvin) Fu, Kun (Kelvin) Fu Department of Materials Science and Engineering, University of Maryland College Park, College Park, MD, 20742 USASearch for more papers by this authorZhengyang Wang, Zhengyang Wang Department of Materials Science and Engineering, University of Maryland College Park, College Park, MD, 20742 USASearch for more papers by this authorChaoyi Yan, Chaoyi Yan Department of Materials Science and Engineering, University of Maryland College Park, College Park, MD, 20742 USASearch for more papers by this authorZhen Liu, Zhen Liu Department of Materials Science and Engineering, University of Maryland College Park, College Park, MD, 20742 USASearch for more papers by this authorYonggang Yao, Yonggang Yao Department of Materials Science and Engineering, University of Maryland College Park, College Park, MD, 20742 USASearch for more papers by this authorJiaqi Dai, Jiaqi Dai Department of Materials Science and Engineering, University of Maryland College Park, College Park, MD, 20742 USASearch for more papers by this authorEmily Hitz, Emily Hitz Department of Materials Science and Engineering, University of Maryland College Park, College Park, MD, 20742 USASearch for more papers by this authorYibo Wang, Yibo Wang Department of Materials Science and Engineering, University of Maryland College Park, College Park, MD, 20742 USASearch for more papers by this authorWei Luo, Wei Luo Department of Materials Science and Engineering, University of Maryland College Park, College Park, MD, 20742 USASearch for more papers by this authorYanan Chen, Yanan Chen Department of Materials Science and Engineering, University of Maryland College Park, College Park, MD, 20742 USASearch for more papers by this authorMyeongseob Kim, Myeongseob Kim BAE Systems, Columbia, MD, 21046 USASearch for more papers by this authorLiangbing Hu, Corresponding Author Liangbing Hu Department of Materials Science and Engineering, University of Maryland College Park, College Park, MD, 20742 USAE-mail: binghu@umd.eduSearch for more papers by this author First published: 07 March 2016 https://doi.org/10.1002/aenm.201502496Citations: 41Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Graphical Abstract Transient energy storage is a novel concept of using transient technology to design a device that can degrade and dissolve into the surrounding environment after being triggered by the external stimulus. A systematic design of a transient lithium-ion battery to achieve high battery performance and all-component transience is reported. Citing Literature Supporting Information As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Filename Description aenm201502496-sup-0001-S1.pdf3.1 MB Supplementary Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article. Volume6, Issue10May 25, 20161502496 RelatedInformation

High temperature heaters are ubiquitously used in materials synthesis and device processing. In this work, we developed three-dimensional (3D) printed reduced graphene oxide (RGO)-based heaters to function as high-performance thermal supply with high temperature and ultrafast heating rate. Compared with other heating sources, such as furnace, laser, and infrared radiation, the 3D printed heaters demonstrated in this work have the following distinct advantages: (1) the RGO based heater can operate at high temperature up to 3000 K because of using the high temperature-sustainable carbon material; (2) the heater temperature can be ramped up and down with extremely fast rates, up to ∼20 000 K/second; (3) heaters with different shapes can be directly printed with small sizes and onto different substrates to enable heating anywhere. The 3D printable RGO heaters can be applied to a wide range of nanomanufacturing when precise temperature control in time, placement, and the ramping rate are important.

Beyond state-of-the-art lithium-ion battery (LIB) technology with metallic lithium anodes to replace conventional ion intercalation anode materials is highly desirable because of lithium's highest specific capacity (3,860 mA/g) and lowest negative electrochemical potential (∼3.040 V vs. the standard hydrogen electrode). In this work, we report for the first time, to our knowledge, a 3D lithium-ion-conducting ceramic network based on garnet-type Li6.4La3Zr2Al0.2O12 (LLZO) lithium-ion conductor to provide continuous Li(+) transfer channels in a polyethylene oxide (PEO)-based composite. This composite structure further provides structural reinforcement to enhance the mechanical properties of the polymer matrix. The flexible solid-state electrolyte composite membrane exhibited an ionic conductivity of 2.5 × 10(-4) S/cm at room temperature. The membrane can effectively block dendrites in a symmetric Li | electrolyte | Li cell during repeated lithium stripping/plating at room temperature, with a current density of 0.2 mA/cm(2) for around 500 h and a current density of 0.5 mA/cm(2) for over 300 h. These results provide an all solid ion-conducting membrane that can be applied to flexible LIBs and other electrochemical energy storage systems, such as lithium-sulfur batteries.

All-component 3D-printed lithium-ion batteries are fabricated by printing graphene-oxide-based composite inks and solid-state gel polymer electrolyte. An entirely 3D-printed full cell features a high electrode mass loading of 18 mg cm(-2) , which is normalized to the overall area of the battery. This all-component printing can be extended to the fabrication of multidimensional/multiscale complex-structures of more energy-storage devices.