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991.
Chanhoon Kim Gaeun Hwang Ji-Won Jung Su-Ho Cho Jun Young Cheong Sunghee Shin Soojin Park Il-Doo Kim 《Advanced functional materials》2017,27(14):1605975
Nanostructuring has significantly contributed to alleviating the huge volume expansion problem of the Ge anodes. However, the practical use of nanostructured Ge anodes has been hindered due to several problems including a low tap density, poor scalability, and severe side reactions. Therefore, micrometer-sized Ge is desirable for practical use of Ge-based anode materials. Here, micronized Ge3N4 with a high tap density of 1.1 mg cm−2 has been successfully developed via a scalable wet oxidation and a subsequent nitridation process of commercially available micrometer-sized Ge as the starting material. The micronized Ge3N4 shows much-suppressed volume expansion compared to micrometer-sized Ge. After the carbon coating process, a thin carbon layer (≈3 nm) is uniformly coated on the micronized Ge3N4, which significantly improves electrical conductivity. As a result, micronized Ge3N4@C shows high reversible capacity of 924 mAh g−1 (2.1 mAh cm−2) with high mass loading of 3.5 mg cm−2 and retains 91% of initial capacity after 300 cycles at a rate of 0.5 C. Additionally, the effectiveness of Ge3N4@C as practical anodes is comprehensively demonstrated for the full cell, showing stable cycle retention and especially excellent rate capability, retaining 47% of its initial capacity at 0.2 C for 12 min discharge/charge condition. 相似文献
992.
Many motion-compensated image reconstruction (MCIR) methods have been proposed to correct for subject motion in medical imaging. MCIR methods incorporate motion models to improve image quality by reducing motion artifacts and noise. This paper analyzes the spatial resolution properties of MCIR methods and shows that nonrigid local motion can lead to nonuniform and anisotropic spatial resolution for conventional quadratic regularizers. This undesirable property is akin to the known effects of interactions between heteroscedastic log-likelihoods (e.g., Poisson likelihood) and quadratic regularizers. This effect may lead to quantification errors in small or narrow structures (such as small lesions or rings) of reconstructed images. This paper proposes novel spatial regularization design methods for three different MCIR methods that account for known nonrigid motion. We develop MCIR regularization designs that provide approximately uniform and isotropic spatial resolution and that match a user-specified target spatial resolution. Two-dimensional PET simulations demonstrate the performance and benefits of the proposed spatial regularization design methods. 相似文献
993.
994.
Jaegeon Ryu Woo‐Jin Song Sangyeop Lee Sungho Choi Soojin Park 《Advanced functional materials》2020,30(2)
The imperative to electrify the transport sector in the past few decades has put millions of electric vehicles on the road worldwide with an extended mile range from critical technological breakthroughs in developing the rechargeable energy storage systems, which also covers electronic devices and smart grid applications. However, the available energy density of prevailing systems in the market (i.e., batteries) is reaching its boundaries due to the limited choice of electrochemical reactions that necessarily depend on the thermodynamics and kinetics of the components (e.g., cathode, anode, electrolyte, separator, and current collectors). Reaching the high energy density of batteries exploits new redox chemistry such as sensitive metal anodes, insulating and highly dissolving sulfur cathodes, etc., thus requiring novel designs of various multiscale functional materials to address the corresponding issues. Here, the recent achievements on the designs of smart functional materials for emerging problems in the whole range of systems are discussed: i) interfacial control/kinetic regulation of Li–S battery; ii) self‐healing‐driven structural stability in the electrode and electrolyte; iii) ion‐sieving functional membranes for selective scavenging capability; and iv) functional materials to ensure battery safety. 相似文献
995.
Thanh Tran‐Phu Rahman Daiyan Zelio Fusco Zhipeng Ma Rose Amal Antonio Tricoli 《Advanced functional materials》2020,30(3)
3D Bi2O3 fractal nanostructures (f‐Bi2O3) are directly self‐assembled on carbon fiber papers (CFP) using a scalable hot‐aerosol synthesis strategy. This approach provides high versatility in modulating the physiochemical properties of the Bi2O3 catalyst by a tailorable control of its crystalline size, loading, electron density as well as providing exposed stacking of the nanomaterials on the porous CFP substrate. As a result, when tested for electrochemical CO2 reduction reactions (CO2RR), these f‐Bi2O3 electrodes demonstrate superior conversion of CO2 to formate (HCOO?) with low onset overpotential and a high mass‐specific formate partial current density of ?52.2 mA mg?1, which is ≈3 times higher than that of the drop‐casted control Bi2O3 catalyst (?15.5 mA mg?1), and a high Faradaic efficiency (FEHCOO?) of 87% at an applied potential of ?1.2 V versus reversible hydrogen electrode. The findings reveal that the high exposure of roughened β‐phase Bi2O3/Bi edges and the improved electron density of these fractal structures are key contributors in attainment of high CO2RR activity. 相似文献
996.
Lu Han Menghao Wang Lizbeth Ofelia Prieto‐Lpez Xu Deng Jiaxi Cui 《Advanced functional materials》2020,30(7)
Adhesive hydrogels are widely applied for biological and medical purposes; however, they are generally unable to adhere to tissues under wet/underwater conditions. Herein, described is a class of novel dynamic hydrogels that shows repeatable and long‐term stable underwater adhesion to various substrates including wet biological tissues. The hydrogels have Fe3+‐induced hydrophobic surfaces, which are dynamic and can undergo a self‐hydrophobization process to achieve strong underwater adhesion to a diverse range of dried/wet substrates without the need for additional processes or reagents. It is also demonstrated that the hydrogels can directly adhere to biological tissues in the presence of under sweat, blood, or body fluid exposure, and that the adhesion is compatible with in vivo dynamic movements. This study provides a novel strategy for fabricating underwater adhesive hydrogels for many applications, such as soft robots, wearable devices, tissue adhesives, and wound dressings. 相似文献
997.
Nan Wei Patrik Laiho Abu Taher Khan Aqeel Hussain Alina Lyuleeva Saeed Ahmed Qiang Zhang Yongping Liao Ying Tian Er‐Xiong Ding Yutaka Ohno Esko I. Kauppinen 《Advanced functional materials》2020,30(5)
In this work, a fast approach for the fabrication of hundreds of ultraclean field‐effect transistors (FETs) is introduced, using single‐walled carbon nanotubes (SWCNTs). The synthesis of the nanomaterial is performed by floating‐catalyst chemical vapor deposition, which is employed to fabricate high‐performance thin‐film transistors. Combined with palladium metal bottom contacts, the transport properties of individual SWCNTs are directly unveiled. The resulting SWCNT‐based FETs exhibit a mean field‐effect mobility, which is 3.3 times higher than that of high‐quality solution‐processed CNTs. This demonstrates that the hereby used SWCNTs are superior to comparable materials in terms of their transport properties. In particular, the on–off current ratios reach over 30 million. Thus, this method enables a fast, detailed, and reliable characterization of intrinsic properties of nanomaterials. The obtained ultraclean SWCNT‐based FETs shed light on further study of contamination‐free SWCNTs on various metal contacts and substrates. 相似文献
998.
Christoph A. Spiegel Marc Hippler Alexander Münchinger Martin Bastmeyer Christopher Barner‐Kowollik Martin Wegener Eva Blasco 《Advanced functional materials》2020,30(26)
3D printing of adaptive and dynamic structures, also known as 4D printing, is one of the key challenges in contemporary materials science. The additional dimension refers to the ability of 3D printed structures to change their properties—for example, shape—over time in a controlled fashion as the result of external stimulation. Within the last years, significant efforts have been undertaken in the development of new responsive materials for printing at the macroscale. However, 4D printing at the microscale is still in its early stages. Thus, this progress report will focus on emerging materials for 4D printing at the microscale as well as their challenges and potential applications. Hydrogels and liquid crystalline and composite materials have been identified as the main classes of materials representing the state of the art of the growing field. For each type of material, the challenges and critical barriers in the material design and their performance in 4D microprinting are discussed. Importantly, further necessary strategies are proposed to overcome the limitations of the current approaches and move toward their application in fields such as biomedicine, microrobotics, or optics. 相似文献
999.
Jiale Xia Hongyang Zhao Bolong Huang Lingling Xu Meng Luo Jianwei Wang Feng Luo Yaping Du Chun‐Hua Yan 《Advanced functional materials》2020,30(9)
Owing to the unique electronic properties, rare‐earth modulations in noble‐metal electrocatalysts emerge as a critical strategy for a broad range of renewable energy solutions such as water‐splitting and metal–air batteries. Beyond the typical doping strategy that suffers from synthesis difficulties and concentration limitations, the innovative introduction of rare‐earth is highly desired. Herein, a novel synthesis strategy is presented by introducing CeO2 support for the nickel–iron–chromium hydroxide (NFC) to boost the oxygen evolution reaction (OER) performance, which achieves an ultralow overpotential at 10 mA cm?2 of 230.8 mV, the Tafel slope of 32.7 mV dec?1, as well as the excellent durability in alkaline solution. Density functional theory calculations prove the established d–f electronic ladders, by the interaction between NFC and CeO2, evidently boosts the high‐speed electron transfer. Meanwhile, the stable valence state in CeO2 preserves the high electronic reactivity for OER. This work demonstrates a promising approach in fabricating a nonprecious OER electrocatalyst with the facilitation of rare‐earth oxides to reach both excellent activity and high stability. 相似文献
1000.
Erpeng Li Enbing Bi Yongzhen Wu Weiwei Zhang Linchang Li Han Chen Liyuan Han He Tian Wei‐Hong Zhu 《Advanced functional materials》2020,30(7)
All organic charge‐transporting layer (CTL)‐featured perovskite solar cells (PSCs) exhibit distinct advantages, but their scaling‐up remains a great challenge because the organic CTLs underneath the perovskite are too thin to achieve large‐area homogeneous layers by spin‐coating, and their hydrophobic nature further hinders the solution‐based fabrication of perovskite layer. Here, an unprecedented anchoring‐based coassembly (ACA) strategy is reported that involves a synergistic coadsorption of a hydrophilic ammonium salt CA‐Br with hole‐transporting triphenylamine derivatives to acquire scalable and wettable organic hole‐extraction monolayers for p–i–n structured PSCs. The ACA route not only enables ultrathin organic CTLs with high uniformity but also eliminates the nonwetting problem to facilitate large‐area perovskite films with 100% coverage. Moreover, incorporation of CA‐Br in the ACA strategy can distinctly guarantee a high quality of electronic connection via the cations' vacancy passivation. Consequently, a high power‐conversion‐efficiency (PCE) of 17.49% is achieved for p–i–n structured PSCs (1.02 cm2), and a module with an aperture area of 36 cm2 shows PCE of 12.67%, one of the best scaling‐up results among all‐organic CTL‐based PSCs. This work demonstrates that the ACA strategy can be a promising route to large‐area uniform interfacial layers as well as scaling‐up of perovskite solar cells. 相似文献