To keep pace with the increasing pursuit of portable and wearable electronics, it is urgent to develop advanced flexible power supplies. In this context, Zn‐ion batteries (ZIBs) have garnered ...increasing attention as favorable energy storage devices for flexible electronics, owing to the high capacity, low cost, abundant resources, high safety, and eco‐friendliness. Extensive efforts have been devoted to developing flexible ZIBs in the last few years. This work summarizes the recent achievements in the design, fabrication, and characterization of flexible ZIBs. Representative structures, such as sandwich and cable type, are particularly highlighted. Special emphasis is put on the novel design of electrolyte and electrode, which aims to endow reliable flexibility to the fabricated ZIBs. Moreover, current challenges and future opportunities for the development of high‐performance flexible ZIBs are also outlined.
The recent development of electrode materials, gel electrolytes, and device configurations for flexible zinc‐ion batteries (ZIBs) is reviewed. Recent progresses in flexible ZIBs are discussed by briefly categorizing into Zn–Mn based, Zn–V based, Zn–Prussian blue analog based, and the other ZIBs. The current challenges and future opportunities for the development of flexible ZIBs are also discussed.
Aqueous alkaline batteries see bright future in renewable energy storage and utilization, but their practical application is greatly challenged by the unsatisfactory performance of anode materials. ...Herein, we demonstrate a latent Sb stripping/plating chemistry by constructing an oxygen-rich interface on carbon substrate, thus providing a decent anode candidate. The functional interface effectively lowers the nucleation overpotential of Sb and strengthens the absorption capability of the charge carriers (SbO
ions). These two advantageous properties inhibit the occurrence of side reactions and thus enable highly reversible Sb stripping/plating. Consequently, the Sb anode delivers theoretical-value-close specific capacity (627.1 mA h g
), high depth of discharge (95.0%) and maintains 92.4% coulombic efficiency over 1000 cycles. A robust aqueous NiCo
O
//Sb device with high energy density and prominent durability is also demonstrated. This work provides a train of thoughts for the development of aqueous alkaline batteries based on Sb chemistry.
Understanding ion transport kinetics and electrolyte-electrode interactions at electrode surfaces of batteries in operation is essential to determine their performance and state of health. However, ...it remains a challenging task to capture in real time the details of surface-localized and rapid ion transport at the microscale. To address this, a promising approach based on an optical fiber plasmonic sensor capable of being inserted near the electrode surface of a working battery to monitor its electrochemical kinetics without disturbing its operation is demonstrated using aqueous Zn-ion batteries as an example. The miniature and chemically inert sensor detects perturbations of surface plasmon waves propagating on its surface to rapidly screen localized electrochemical events on a sub-μm-scale thickness adjacent to the electrode interface. A stable and reproducible correlation between the real-time ion insertions over charge-discharge cycles and the optical plasmon response has been observed and quantified. This new operando measurement tool will provide crucial additional capabilities to battery monitoring methods and help guide the design of better batteries with improved electro-chemistries.
Zinc‐ion hybrid supercapacitors (ZHSCs) have garnered increasing attention as promising energy storage devices in recent years, as they combine the advantages of high‐energy Zn‐ion batteries and ...high‐power supercapacitors. However, the development of ZHSCs is still in its infancy and there are many bottlenecks to overcome. In particular, the challenge induced by the limited ion adsorption capability of carbon‐positive electrodes severely restricts the energy density of ZHSCs. Therefore, it has become a key issue to design novel carbon‐positive electrodes that enable high energy density yet do not deteriorate the intrinsic power capability and long‐term durability. This study focuses on recent achievements in synthesis, morphology, and electrochemical performance of various carbon materials applied in ZHSCs. The modification strategies to optimize their electrochemical performance are briefly summarized. In addition, current challenges and future opportunities in this field are also outlined. This review will be beneficial to provide an organized framework for the research systems of carbon‐positive electrodes and develop novel ZHSCs with high energy density.
This review provides an overview on the recent progress of carbon materials as positive electrodes in zinc‐ion hybrid supercapacitors. The electrochemical performance of different types of carbon materials is compared and the relevant modification strategies are summarized.
The performance of pseudocapacitive electrodes at fast charging rates are typically limited by the slow kinetics of Faradaic reactions and sluggish ion diffusion in the bulk structure. This is ...particularly problematic for thick electrodes and electrodes highly loaded with active materials. Here, a surface‐functionalized 3D‐printed graphene aerogel (SF‐3D GA) is presented that achieves not only a benchmark areal capacitance of 2195 mF cm−2 at a high current density of 100 mA cm−2 but also an ultrahigh intrinsic capacitance of 309.1 µF cm−2 even at a high mass loading of 12.8 mg cm−2. Importantly, the kinetic analysis reveals that the capacitance of SF‐3D GA electrode is primarily (93.3%) contributed from fast kinetic processes. This is because the 3D‐printed electrode has an open structure that ensures excellent coverage of functional groups on carbon surface and facilitates the ion accessibility of these surface functional groups even at high current densities and large mass loading/electrode thickness. An asymmetric device assembled with SF‐3D GA as anode and 3D‐printed GA decorated with MnO2 as cathode achieves a remarkable energy density of 0.65 mWh cm−2 at an ultrahigh power density of 164.5 mW cm−2, outperforming carbon‐based supercapacitors operated at the same power density.
A surface‐functionalized 3D‐printed graphene aerogel achieves a benchmark areal capacitance of 2195 mF cm−2 and an ultrahigh intrinsic capacitance of 309.1 µF cm−2. This work demonstrates the essential role of 3D‐printed porous structure for simultaneously boosting the kinetics and intrinsic capacitance of thick carbon electrodes with high mass loadings.
Electroretinogram examinations serve as routine clinical procedures in ophthalmology for the diagnosis and management of many ocular diseases. However, the rigid form factor of current corneal ...sensors produces a mismatch with the soft, curvilinear, and exceptionally sensitive human cornea, which typically requires the use of topical anesthesia and a speculum for pain management and safety. Here we report a design of an all-printed stretchable corneal sensor built on commercially-available disposable soft contact lenses that can intimately and non-invasively interface with the corneal surface of human eyes. The corneal sensor is integrated with soft contact lenses via an electrochemical anchoring mechanism in a seamless manner that ensures its mechanical and chemical reliability. Thus, the resulting device enables the high-fidelity recording of full-field electroretinogram signals in human eyes without the need of topical anesthesia or a speculum. The device, superior to clinical standards in terms of signal quality and comfortability, is expected to address unmet clinical needs in the field of ocular electrodiagnosis.
Maintaining fast charging capability at low temperatures represents a significant challenge for supercapacitors. The performance of conventional porous carbon electrodes often deteriorates quickly ...with the decrease of temperature due to sluggish ion and charge transport. Here we fabricate a 3D-printed multiscale porous carbon aerogel (3D-MCA) via a unique combination of chemical methods and the direct ink writing technique. 3D-MCA has an open porous structure with a large surface area of ∼1750 m2 g–1. At −70 °C, the symmetric device achieves outstanding capacitance of 148.6 F g–1 at 5 mV s–1. Significantly, it retains a capacitance of 71.4 F g–1 at a high scan rate of 200 mV s–1, which is 6.5 times higher than the non-3D printed MCA. These values rank among the best results reported for low temperature supercapacitors. These impressive results highlight the essential role of open porous structures for preserving capacitive performance at ultralow temperatures.
The present study investigates the effect of tourism and its spatial correlation on urban economic growth. The study examines 272 prefecture-level administrative units between 2002 and 2011 in China ...as the sample and a β convergence model as the frame. The conclusions are that tourism development has a substantial impact on urban economic growth in China without decreasing the economic gap among cities. The tourism growth effect contributed primarily in the development of positive spatial correlation that led to spatial spill-overs—a large indirect effect; the direct effect of tourism on local economies was minimal. Introducing spatial correlation analysis of the relationship between tourism and urban economic development avoids reaching misleading conclusions and enables the analysis of both direct and indirect effects of tourism development.
In air pollution studies, the correlation analysis of environmental variables has usually been challenged by parametric diversity. Such variable variations are not only from the extrinsic ...meteorological conditions and industrial activities but also from the interactive influences between the multiple parameters. A promising solution has been motivated by the recent development of visibility graph (VG) on multi-variable data analysis, especially for the characterization of pollutants' correlation in the temporal domain, the multiple visibility graph (MVG) for nonlinear multivariate time series analysis has been verified effectively in different realistic scenarios. To comprehensively study the correlation between pollutant data and season, in this work, we propose a multi-layer complex network with a community division strategy based on the joint analysis of the atmospheric pollutants. Compared to the single-layer-based complex networks, our proposed method can integrate multiple different atmospheric pollutants for analysis, and combine them with multivariate time series data to obtain higher temporary community division for ground air pollutants interpretation. Substantial experiments have shown that this method effectively utilizes air pollution data from multiple representative indicators. By mining community information in the data, it successfully achieves reasonable and strong interpretive analysis of air pollution data.
Abstract
Recent advances in MXene (Ti
3
C
2
T
x
) fibers, prepared from electrically conductive and mechanically strong MXene nanosheets, address the increasing demand of emerging yet promising ...electrode materials for the development of textile-based devices and beyond. However, to reveal the full potential of MXene fibers, reaching a balance between electrical conductivity and mechanical property is still the fundamental challenge, mainly due to the difficulties to further compact the loose MXene nanosheets. In this work, we demonstrate a continuous and controllable route to fabricate ultra-compact MXene fibers with an in-situ generated protective layer via the synergy of interfacial interactions and thermal drawing-induced stresses. The resulting ultra-compact MXene fibers with high orientation and low porosity exhibit not only excellent tensile strength and ultra-high toughness, but also high electrical conductivity. Then, we construct meter-scale MXene textiles using these ultra-compact fibers to achieve high-performance electromagnetic interference shielding and personal thermal management, accompanied by the high mechanical durability and stability even after multiple washing cycles. The demonstrated generic strategy can be applied to a broad range of nanostructured materials to construct functional fibers for large-scale applications in both space and daily lives.
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