Pseudocapacitive materials generally offer both high capacitance and high rate capability, which has stimulated great efforts in developing the materials system and related energy storage devices. In ...recent years, however, with the extensive use of nanomaterials in batteries, fast redox kinetics comparable to pseudocapacitive have been achieved in many kinds of battery materials due to the much shortened ion diffusion lengths and highly exposed surface/interface as a result of nanosize effect. Consequently, the terms “pseudocapacitive materials” and “battery materials” are becoming more and more confusing. In this review, different opinions on the definition of pseudocapacitive materials and the evolution of the definitions as well as the resulting confusion will be firstly reviewed. Then, to accurately distinguish pseudocapacitive and battery materials, method with the consideration of both the electrochemical signatures (CVs and GCD) and quantitative kinetics analysis as a supplement is proposed. Finally, we end this review by discussing the possible device configurations of asymmetric supercapacitors and hybrid supercapacitors. The present review will help understanding the differences between pseudocapacitive materials and battery materials, and thus avoiding the definition confusion.
This review firstly discusses different opinions on the definition of pseudocapacitive materials and the evolution of the definitions as well as the resulting confusion. Method to accurately distinguish pseudocapacitive and battery materials is then proposed. In addition, the definitions of asymmetric supercapacitors and hybrid supercapacitors are clarified.
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We have developed a supercapacitor electrode composed of well-aligned CoO nanowire array grown on 3D nickel foam with polypyrrole (PPy) uniformly immobilized onto or firmly anchored to each nanowire ...surface to boost the pseudocapacitive performance. The electrode architecture takes advantage of the high electrochemical activity from both the CoO and PPy, the high electronic conductivity of PPy, and the short ion diffusion pathway in ordered mesoporous nanowires. These merits together with the elegant synergy between CoO and PPy lead to a high specific capacitance of 2223 F g–1 approaching the theoretical value, good rate capability, and cycling stability (99.8% capacitance retention after 2000 cycles). An aqueous asymmetric supercapacitor device with a maximum voltage of 1.8 V fabricated by using our hybrid array as the positive electrode and activated carbon film as the negative electrode has demonstrated high energy density (∼43.5 Wh kg–1), high power density (∼5500 W kg–1 at 11.8 Wh kg–1) and outstanding cycleability (∼20 000 times). After charging for only ∼10 s, two such 4 cm2 asymmetric supercapacitors connected in series can efficiently power 5 mm diameter red, yellow, and green round LED indicators (lasting for 1 h for red LED) and drive a mini 130 rotation-motor robustly.
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IJS, KILJ, NUK, PNG, UL, UM
One of the key challenges of aqueous supercapacitors is the relatively low voltage (0.8–2.0 V), which significantly limits the energy density and feasibility of practical applications of the device. ...Herein, this study reports a novel Ni–Mn–O solid‐solution cathode to widen the supercapacitor device voltage, which can potentially suppress the oxygen evolution reaction and thus be operated stably within a quite wide potential window of 0–1.4 V (vs saturated calomel electrode) after a simple but unique phase‐transformation electrochemical activation. The solid‐solution structure is designed with an ordered array architecture and in situ nanocarbon modification to promote the charge/mass transfer kinetics. By paring with commercial activated carbon anode, an ultrahigh voltage asymmetric supercapacitor in neutral aqueous LiCl electrolyte is assembled (2.4 V; among the highest for single‐cell supercapacitors). Moreover, by using a polyvinyl alcohol (PVA)–LiCl electrolyte, a 2.4 V hydrogel supercapacitor is further developed with an excellent Coulombic efficiency, good rate capability, and remarkable cycle life (>5000 cycles; 95.5% capacity retention). Only one cell can power the light‐emitting diode indicator brightly. The resulting maximum volumetric energy density is 4.72 mWh cm−3, which is much superior to previous thin‐film manganese‐oxide‐based supercapacitors and even battery–supercapacitor hybrid devices.
A very simple but unique phase‐transformation electrochemical activation strategy is developed to enable a solid‐solution Ni–Mn–O nanoprism array to suppress the oxygen evolution and exhibit ultrawide stable electrochemical window (0–1.4 V vs saturated calomel electrode). With such as an array as the cathode, a 2.4 V ultrahigh voltage aqueous supercapacitor is constructed, demonstrating high volumetric energy/power densities.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The ever‐growing demands for green and sustainable power sources for applications in grid‐scale energy storage and portable/wearable devices have enabled the continual development of advanced aqueous ...electrochemical energy storage (EES) systems. Aqueous batteries and supercapacitors made of iron‐based anodes are one of the most promising options due to the remarkable electrochemical features and natural abundance, pretty low cost and good environmental friendliness of ferruginous species. Though impressive advances in developing the state‐of‐the‐art ferruginous anodes and designing various full‐cell aqueous devices have been made, there still remain key issues and challenges on the way to practical applications, which urgently need discussing to put forwards possible solutions. In this review, rather than focusing on the detailed methods to optimize the iron anode, electrolyte, and device performance, we first give a comprehensive review on the charge storage mechanisms for ferruginous anodes in different electrolyte systems, as well as the newly developed iron‐based aqueous EES devices. The deep insights, involving the inherent failure mechanisms and corresponding modification/optimization strategies toward iron anodes for the development of high‐performance aqueous EES devices, will then be discussed. The advances in applying iron‐based aqueous EES devices for emerging fields such as flexible/wearable electronics and functionalized building materials will be further outlined. Last, future research trends and perspectives for maximizing the potential of current iron anodes and devices as well as exploiting brand‐new iron‐based aqueous EES systems are put forward.
A comprehensive overview of charge‐storage mechanisms for ferruginous anodes in different aqueous electrolytes, and newly developed iron‐based electrochemical energy storage devices is presented. The iron anode failure mechanisms and corresponding optimization strategies are discussed. Future research trends and perspectives for maximizing the potential of current iron anodes and devices are proposed.
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In Alzheimer's disease (AD), early synaptic dysfunction is associated with the increased oligomeric amyloid-beta peptide, which causes NMDAR-dependent synaptic depression and spine elimination. ...Memantine, low-affinity NMDAR channel blocker, has been used in the treatment of moderate to severe AD. However, clear evidence is still deficient in demonstrating the underlying mechanisms and a relationship between NMDARs dysfunction and AD. This review focuses on not only changes in expression of different NMDAR subunits, but also some unconventional modes of NMDAR action.
MnO2 is one of the most studied cathodes for aqueous neutral zinc‐ion batteries. However, the diverse reported crystal structures of MnO2 compared to δ‐MnO2 inevitably suffer a structural phase ...transition from tunneled to layered Zn‐buserite during the initial cycles, which is not as kinetically direct as the conventional intercalation electrochemistry in layered materials and thus poses great challenges to the performance and multifunctionality of devices. Here, a binder‐free δ‐MnO2 cathode is designed and a favorable “layered to layered” Zn2+ storage mechanism is revealed systematically using such a “noninterferencing” electrode platform in combination with ab initio calculation. A flexible quasi‐solid‐state Zn–Mn battery with an electrodeposited flexible Zn anode is further assembled, exhibiting high energy density (35.11 mWh cm−3; 432.05 Wh kg−1), high power density (676.92 mW cm−3; 8.33 kW kg−1), extremely low self‐discharge rate, and ultralong stability up to 10 000 cycles. Even with a relatively high δ‐MnO2 mass loading of 5 mg cm−2, significant energy and power densities are still achieved. The device also works well over a broad temperature range (0–40 °C) and can efficiently power different types of small electronics. This work provides an opportunity to develop high‐performance multivalent‐ion batteries via the design of a kinetically favorable host structure.
A “layered to layered” mechanism for zinc storage in δ‐MnO2 is revealed based on a binder‐/additive‐free “noninterferencing” electrode platform. A δ‐MnO2‐based flexible quasi‐solid‐state zinc–manganese battery is further designed, which achieves high energy density, high power density, and outstanding cycling stability up to 10 000 times and exhibits good mechanical properties and a low self‐discharge rate.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Genomic analyses of primary liver cancer samples reveal a complex mutational landscape with vast intertumor and intratumor heterogeneity. Different primary liver tumors and subclones within each ...tumor display striking molecular and biological variations. Consequently, tumor molecular heterogeneity contributes to drug resistance and tumor relapse following therapy, which poses a substantial obstruction to improving outcomes of patients with liver cancer. There is an urgent need to the compositional and functional understanding of tumor heterogeneity. In this review, we summarize genomic and non-genomic diversities, which include stemness and microenvironmental causes of the functional heterogeneity of the primary liver cancer ecosystem. We discuss the importance and intricacy of intratumor heterogeneity in the context of cancer cell evolution. We also discuss methodologies applicable to determine intratumor heterogeneity and highlight the best-fit patient-derived in vivo and in vitro models to recapture the functional heterogeneity of primary liver cancer with the aim to improve future therapeutic strategies.
Design and fabrication of electrochemical energy storage systems with both high energy and power densities as well as long cycling life is of great importance. As one of these systems, ...Battery‐supercapacitor hybrid device (BSH) is typically constructed with a high‐capacity battery‐type electrode and a high‐rate capacitive electrode, which has attracted enormous attention due to its potential applications in future electric vehicles, smart electric grids, and even miniaturized electronic/optoelectronic devices, etc. With proper design, BSH will provide unique advantages such as high performance, cheapness, safety, and environmental friendliness. This review first addresses the fundamental scientific principle, structure, and possible classification of BSHs, and then reviews the recent advances on various existing and emerging BSHs such as Li‐/Na‐ion BSHs, acidic/alkaline BSHs, BSH with redox electrolytes, and BSH with pseudocapacitive electrode, with the focus on materials and electrochemical performances. Furthermore, recent progresses in BSH devices with specific functionalities of flexibility and transparency, etc. will be highlighted. Finally, the future developing trends and directions as well as the challenges will also be discussed; especially, two conceptual BSHs with aqueous high voltage window and integrated 3D electrode/electrolyte architecture will be proposed.
The fundamental scientific principle, structure, and possible classification of battery‐supercapacitor hybrid devices (BSHs), outlining the recent advances on various existing and emerging BSHs, with the focus on materials and electrochemical performances, and finally providing the future developing trends and directions as well as the challenges are addressed in this review.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Lithium ion battery (LIB) is potentially one of the most attractive energy storage devices. To meet the demands of future high-power and high-energy density requirements in both thin-film ...microbatteries and conventional batteries, it is challenging to explore novel nanostructured anode materials instead of conventional graphite. Compared to traditional electrodes based on nanostructure powder paste, directly grown ordered nanostructure array electrodes not only simplify the electrode processing, but also offer remarkable advantages such as fast electron transport/collection and ion diffusion, sufficient electrochemical reaction of individual nanostructures, enhanced material-electrolyte contact area and facile accommodation of the strains caused by lithium intercalation and de-intercalation. This article provides a brief overview of the present status in the area of LIB anodes based on one-dimensional nanostructure arrays growing directly on conductive inert metal substrates, with particular attention to metal oxides synthesized by an anodized alumina membrane (AAM)-free solution-based or hydrothermal methods. Both the scientific developments and the techniques and challenges are critically analyzed.
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A novel synergistic TiO2‐MoO3 (TO‐MO) core–shell nanowire array anode has been fabricated via a facile hydrothermal method followed by a subsequent controllable electrodeposition process. The ...nano‐MoO3 shell provides large specific capacity as well as good electrical conductivity for fast charge transfer, while the highly electrochemically stable TiO2 nanowire core (negligible volume change during Li insertion/desertion) remedies the cycling instability of MoO3 shell and its array further provides a 3D scaffold for large amount electrodeposition of MoO3. In combination of the unique electrochemical attributes of nanostructure arrays, the optimized TO‐MO hybrid anode (mass ratio: ca. 1:1) simultaneously exhibits high gravimetric capacity (ca. 670 mAh g−1; approaching the hybrid's theoretical value), excellent cyclability (>200 cycles) and good rate capability (up to 2000 mA g−1). The areal capacity is also as high as 3.986 mAh cm−2, comparable to that of typical commercial LIBs. Furthermore, the hybrid anode was assembled for the first time with commercial LiCoO2 cathode into a Li ion full cell, which shows outstanding performance with maximum power density of 1086 W kgtotal
−1 (based on the total mass of the TO‐MO and LiCoO2) and excellent energy density (285 Wh kgtotal
−1) that is higher than many previously reported metal oxide anode‐based Li full cells.
Synergistic TiO2‐MoO3 core–shell nanowire array anode is developed, showing high capacity (ca. 670 mAh g−1; 3.986 mAh cm−2), excellent cycleability (>200 times), and good rate performance. Ultrahigh energy density (285 Wh kgtotal −1) and power density (1086 W kgtotal −1) are further achieved for a full cell LIB device assembled using the TiO2‐MoO3 hybrid array as anode and commercial LiCoO2 film as cathode.
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