Hebei University

Rechargeable zinc-ion batteries (ZIBs) are promising for large scale energy storage and portable electronic applications due to their low cost, material abundance, high safety, acceptable energy density and environmental friendliness. This tutorial review presents an introduction to the fundamentals, challenges, recent advances and prospects related to ZIBs. Firstly, the intrinsic chemical properties, challenges and strategies of metallic zinc anodes are underscored. Then, the multiple types of cathode materials are classified and comparatively discussed in terms of their structural and electrochemical properties, issues and remedies. Specific attention is paid to the mechanistic understanding and structural transformation of cathode materials based on Zn ion-(de)intercalation chemistry. After that, the widely investigated electrolytes are elaborated by discussing their effect on Zn plating/stripping behaviours, reaction kinetics, electrode/electrolyte interface chemistries, and cell performances. Finally, the remaining challenges and future perspectives are outlined for the development of ZIBs.

We report an aqueous Zn–V2O5 battery chemistry employing commercial V2O5 cathode, Zn anode, and 3 M Zn(CF3SO3)2 electrolyte. We elucidate the Zn-storage mechanism in the V2O5 cathode to be that hydrated Zn2+ can reversibly (de)intercalate through the layered structure. The function of the co-intercalated H2O is revealed to be shielding the electrostatic interactions between Zn2+ and the host framework, accounting for the enhanced kinetics. In addition, the pristine bulk V2O5 gradually evolves into porous nanosheets upon cycling, providing more active sites for Zn2+ storage and thus rendering an initial capacity increase. As a consequence, a reversible capacity of 470 mAh g–1 at 0.2 A g–1 and a long-term cyclability with 91.1% capacity rentention over 4000 cycles at 5 A g–1 are achieved. The combination of the good battery performance, safety, scalable materials synthesis, and facile cell assembly indicates this aqueous Zn–V2O5 system is promising for stationary grid storage applications.

Abstract Antimony selenide (Sb 2 Se 3 ) has a one-dimensional (1D) crystal structure comprising of covalently bonded (Sb 4 Se 6 ) n ribbons stacking together through van der Waals force. This special structure results in anisotropic optical and electrical properties. Currently, the photovoltaic device performance is dominated by the grain orientation in the Sb 2 Se 3 thin film absorbers. Effective approaches to enhance the carrier collection and overall power-conversion efficiency are urgently required. Here, we report the construction of Sb 2 Se 3 solar cells with high-quality Sb 2 Se 3 nanorod arrays absorber along the [001] direction, which is beneficial for sun-light absorption and charge carrier extraction. An efficiency of 9.2%, which is the highest value reported so far for this type of solar cells, is achieved by junction interface engineering. Our cell design provides an approach to further improve the efficiency of Sb 2 Se 3 -based solar cells.

Abstract Rechargeable aqueous zinc batteries have gained considerable attention for large‐scale energy storage systems because of their low cost and high safety, but they suffer from limitations in cycling stability and energy density with advanced cathode materials. Here, a high‐performance V 5 O 12 ·6H 2 O (VOH) nanobelt cathode uniformly located on a stainless‐steel substrate via a facile electrodeposition technique is reported. We show that the hydrated layered VOH cathode enables highly reversible and ultrafast Zn 2+ cation (de)intercalation processes, as confirmed by various electrochemical, X‐ray diffraction, X‐ray photoelectron spectroscopy, and transmission electron microscopy analyses. It is demonstrated that the binder‐free VOH cathode can deliver a discharge capacity of 354.8 mAh g −1 at 0.5 A g −1 with a high initial Coulombic efficiency of 99.5%, a high energy density of 194 Wh kg −1 at 2100 W kg −1 , and a long cycle life with a capacity retention of 94% over 1000 cycles. In addition, a flexible quasi‐solid‐state Zn–VOH battery is constructed, achieving a reversible capacity of ≈300 mAh g −1 with a capacity retention of 96% after 50 cycles and displaying excellent electrochemical behaviors under different bending states. This work sheds light on the development of rechargeable aqueous zinc batteries for stationary grid storage applications or flexible energy storage devices.

Protein kinases are major players in various signal transduction pathways. Understanding the molecular mechanisms behind plant responses to biotic and abiotic stresses has become critical for developing and breeding climate-resilient crops. In this review, we summarize recent progress on understanding plant drought, salt, and cold stress responses, with a focus on signal perception and transduction by different protein kinases, especially sucrose nonfermenting1 (SNF1)-related protein kinases (SnRKs), mitogen-activated protein kinase (MAPK) cascades, calcium-dependent protein kinases (CDPKs/CPKs), and receptor-like kinases (RLKs). We also discuss future challenges in these research fields.

All-inorganic perovskite solar cells provide a promising solution to tackle the thermal instability problem of organic–inorganic perovskite solar cells (PSCs). Herein, we designed an all-inorganic perovskite solar cell with novel structure (FTO/NiOx/CsPbI2Br/ZnO@C60/Ag), in which ZnO@C60 bilayer was utilized as the electron-transporting layers that demonstrated high carrier extraction efficiency and low leakage loss. Consequently, the as-fabricated all-inorganic CsPbI2Br perovskite solar cell yielded a power conversion efficiency (PCE) as high as 13.3% with a Voc of 1.14 V, Jsc of 15.2 mA·cm–2, and FF of 0.77. The corresponding stabilized power output (SPO) of the device was demonstrated to be ∼12% and remarkably stable within 1000 s. Importantly, the obtained all-inorganic PSCs without encapsulation exhibited only 20% PCE loss with thermal treatment at 85 °C for 360 h, which largely outperformed the organic-species-containing PSCs. The present study demonstrates potential in overcoming the intractable issue concerning the thermal instability of perovskite solar cells.

We here first proposed a yolk-shell Co3O4@metal-organic frameworks (MOFs) nanoreactor via a facile method to accommodate sulfate radical-based advanced oxidation processes (SR-AOPs) into its interior cavity. The mesoporous and adsorptive MOFs shells allow the rapid diffusion of reactant molecules to the encapsulated Co3O4 active sites, and the confined high instantaneous concentration of reactants in the local void space is anticipated to facilitate the SR-AOPs. As a proof of concept, the nanoreactor was fully characterized and applied for catalytic degradation of 4-chlorophenol (4-CP) in the presence of peroxymonosulfate (PMS). The enhancement of SR-AOPs in the nanoreactor is demonstrated by the result that degradation efficiency of 4-CP reached almost 100% within 60 min by using the yolk-shell Co3O4@MOFs catalysts as compared to only 59.6% under the same conditions for bare Co3O4 NPs. Furthermore, the applicability of this nanoreactor used in SR-AOPs was systematically investigated in terms of effect of reaction parameters and identification of intermediates and primary radical as well as mineralization of the reaction and stability of the composite. The findings of this study elucidated a new opportunity for improved environmental remediation.

Tiny amounts of a given miRNA (0.1 zmol) can be detected accurately and quantitatively by a real-time method based on an exponential amplification reaction (see picture). The proposed method has a wide dynamic range of more than 10 orders of magnitude, can be carried out within 30 minutes under isothermal conditions, and requires no modified DNA probes. It clearly discriminates miRNA sequences that differ by one base. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. 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.

Abstract Hepatocellular carcinoma (HCC) represents a paradigm of the relation between tumor microenvironment (TME) and tumor development. Here, we generate a single-cell atlas of the multicellular ecosystem of HCC from four tissue sites. We show the enrichment of central memory T cells (T CM ) in the early tertiary lymphoid structures (E-TLSs) in HCC and assess the relationships between chronic HBV/HCV infection and T cell infiltration and exhaustion. We find the MMP9 + macrophages to be terminally differentiated tumor-associated macrophages (TAMs) and PPARγ to be the pivotal transcription factor driving their differentiation. We also characterize the heterogeneous subpopulations of malignant hepatocytes and their multifaceted functions in shaping the immune microenvironment of HCC. Finally, we identify seven microenvironment-based subtypes that can predict prognosis of HCC patients. Collectively, this large-scale atlas deepens our understanding of the HCC microenvironment, which might facilitate the development of new immune therapy strategies for this malignancy.

Involvement of dimethyl carbonate and trifluoromethanesulfonate anions in a hybrid aqueous electrolyte enables the formation of a new Zn²⁺-solvation structure and a ZnF₂–ZnCO₃-rich interphase that stabilizes the Zn battery chemistry.

Abstract From Deep Blue to AlphaGo, artificial intelligence and machine learning are booming, and neural networks have become the hot research direction. However, due to the size limit of complementary metal–oxide–semiconductor (CMOS) transistors, von Neumann‐based computing systems are facing multiple challenges (such as memory walls). As the number of transistors required by the neural network increases, the development of neural networks based on the von Neumann computer is limited by volume and energy consumption. As the fourth basic circuit element, memristor shines in the field of neuromorphic computing. The new computer architecture based on memristor is widely considered as a substitute for the von Neumann architecture and has great potential to deal with the neural network and big data era challenge. This article reviews existing materials and structures of memristors, neurophysiological simulations based on memristors, and applications of memristor‐based neural networks. The feasibility and advancement of implementing neural networks using memristors are discussed, the difficulties that need to be overcome at this stage are put forward, and their development prospects and challenges faced are also discussed.

Automatic assessing the location and extent of liver and liver tumor is critical for radiologists, diagnosis and the clinical process. In recent years, a large number of variants of U-Net based on Multi-scale feature fusion are proposed to improve the segmentation performance for medical image segmentation. Unlike the previous works which extract the context information of medical image via applying the multi-scale feature fusion, we propose a novel network named Multi-scale Attention Net (MA-Net) by introducing self-attention mechanism into our method to adaptively integrate local features with their global dependencies. The MA-Net can capture rich contextual dependencies based on the attention mechanism. We design two blocks: Position-wise Attention Block (PAB) and Multi-scale Fusion Attention Block (MFAB). The PAB is used to model the feature interdependencies in spatial dimensions, which capture the spatial dependencies between pixels in a global view. In addition, the MFAB is to capture the channel dependencies between any feature map by multi-scale semantic feature fusion. We evaluate our method on the dataset of MICCAI 2017 LiTS Challenge. The proposed method achieves better performance than other state-of-the-art methods. The Dice values of liver and tumors segmentation are 0.960 ± 0.03 and 0.749 ± 0.08 respectively.

Rough sets and fuzzy sets have been proved to be powerful mathematical tools to deal with uncertainty, it soon raises a natural question of whether it is possible to connect rough sets and fuzzy sets. The existing generalizations of fuzzy rough sets are all based on special fuzzy relations (fuzzy similarity relations, T-similarity relations), it is advantageous to generalize the fuzzy rough sets by means of arbitrary fuzzy relations and present a general framework for the study of fuzzy rough sets by using both constructive and axiomatic approaches. In this paper, from the viewpoint of constructive approach, we first propose some definitions of upper and lower approximation operators of fuzzy sets by means of arbitrary fuzzy relations and study the relations among them, the connections between special fuzzy relations and upper and lower approximation operators of fuzzy sets are also examined. In axiomatic approach, we characterize different classes of generalized upper and lower approximation operators of fuzzy sets by different sets of axioms. The lattice and topological structures of fuzzy rough sets are also proposed. In order to demonstrate that our proposed generalization of fuzzy rough sets have wider range of applications than the existing fuzzy rough sets, a special lower approximation operator is applied to a fuzzy reasoning system, which coincides with the Mamdani algorithm.

Understanding the interaction mechanisms between nanomaterials and biological cells is important for the control and manipulation of these interactions for biomedical applications. In this study, we investigated the cellular effects of gold nanoparticles (AuNPs) on the differentiation of mesenchymal stem cells (MSCs) and the associated molecular mechanisms. The results showed that AuNPs promoted the differentiation of MSCs toward osteoblast cells over adipocyte cells by inducing an enhanced osteogenic transcriptional profile and an attenuated adipogenic transcriptional profile. AuNPs exerted the effects by interacting with the cell membrane and binding with proteins in the cytoplasm, causing mechanical stress on the MSCs to activate p38 mitogen-activated protein kinase pathway (MAPK) signaling pathway, which regulates the expression of relevant genes to induce osteogenic differentiation and inhibit adipogenic differentiation.

Abstract Memristor, based on the principle of biological synapse, is recognized as one of the key devices in confronting the bottleneck of classical von Neumann computers. However, conventional memristors are difficult to continuously adjust the conduction and dutifully mimic the biosynapse function. Here, TiO 2 films with self‐assembled Ag nanoclusters implemented by gradient Ag dopant are employed to achieve enhanced memristor performance. The memristors exhibit gradual both potentiating and depressing conduction under positive and negative pulse trains, which can fully emulate excitation and inhibition of biosynapse. Moreover, comprehensive biosynaptic functions and plasticity, including the transition from short‐term memory to long‐term memory, long‐term potentiation and depression, spike‐timing‐dependent plasticity, and paired‐pulse facilitation, are implemented with the fabricated memristors in this work. The applied pulses with a width of hundreds of nanoseconds timescale are beneficial to realize fast learning and computing. High‐resolution transmission electron microscopy observations clearly demonstrate that Ag clusters redistribute to form Ag conductive filaments between Ag and Pt electrode under electrical field at ON‐state device. The experimental data confirm that the oxides doped with Ag clusters have the potential for mimicking biosynaptic behavior, which is essential for the further creation of artificial neural systems.

The aim of this study was to determine the size-dependent penetration ability of gold nanoparticles and the potential application of ultrasmall gold nanoparticles for intranucleus delivery and therapy. We synthesized gold nanoparticles with diameters of 2, 6, 10, and 16 nm and compared their intracellular distribution in MCF-7 breast cancer cells. Nanoparticles smaller than 10 nm (2 and 6 nm) could enter the nucleus, whereas larger ones (10 and 16 nm) were found only in the cytoplasm. We then investigated the possibility of using ultrasmall 2 nm nanoparticles as carriers for nuclear delivery of a triplex-forming oligonucleotide (TFO) that binds to the c-myc promoter. Compared to free TFO, the nanoparticle-conjugated TFO was more effective at reducing c-myc RNA and c-myc protein, which resulted in reduced cell viability. Our result demonstrated that the entry of gold nanoparticles into the cell nucleus is critically dependent on the size of the nanoparticles. We developed a strategy for regulating gene expression, by directly delivering TFOs into the nucleus using ultrasmall gold nanoparticles. More importantly, guidelines were provided to choose appropriate nanocarriers for different biomedical purposes.

One-nucleotide differences in microRNAs (miRNAs) can be discriminated in an assay based on a branched rolling-circle amplification (BRCA) reaction and fluorescence quantification. With the proposed method miRNA can be detected at concentrations as low as 10 fM, and the miRNA in a total RNA sample of a few nanograms can be determined.

Abstract Lithium–sulfur batteries are regarded as promising candidates for energy storage devices due to their high theoretical energy density. Various approaches are proposed to break through the obstacles that are preventing Li–S batteries from realizing practical application. Recently, the importance of the strong chemical interaction between polar materials and polysulfides is recognized by researchers to improve the performance of Li–S batteries, especially with respect to the shuttle effect. Polar materials, unlike nonpolar materials, exhibit strong interactions with polysulfides without any modification or doping because of their intrinsic polarity, absorbing the polar polysulfides and thus suppressing the notorious shuttle effect. The recent advances on polar materials for Li–S batteries are reviewed here, especially the chemical polar–polar interaction effects toward immobilizing dissolved polysulfides, and the relationship between the intrinsic properties of the polar materials and the electrochemical performance of the Li–S batteries are discussed. Polar materials, including polar inorganics in the cathode and polar organics as binder for the Li–S batteries are respectively described. Finally, future directions and prospects for the polar materials used in Li–S batteries are also proposed.

Abstract Memristors with nonvolatile memory characteristics have been expected to open a new era for neuromorphic computing and digital logic. However, existing memristor devices based on oxygen vacancy or metal‐ion conductive filament mechanisms generally have large operating currents, which are difficult to meet low‐power consumption requirements. Therefore, it is very necessary to develop new materials to realize memristor devices that are different from the mechanisms of oxygen vacancy or metal‐ion conductive filaments to realize low‐power operation. Herein, high‐performance and low‐power consumption memristors based on 2D WS 2 with 2H phase are demonstrated, which show fast ON (OFF) switching times of 13 ns (14 ns), low program current of 1 µA in the ON state, and SET (RESET) energy reaching the level of femtojoules. Moreover, the memristor can mimic basic biological synaptic functions. Importantly, it is proposed that the generation of sulfur and tungsten vacancies and electron hopping between vacancies are dominantly responsible for the resistance switching performance. Density functional theory calculations show that the defect states formed by sulfur and tungsten vacancies are at deep levels, which prevent charge leakage and facilitate the realization of low‐power consumption for neuromorphic computing application.

The highly developed crystallization process with respect to perovskite thin films is favorable for efficient solar cells. Here, an innovative intermolecular self-assembly approach was employed to retard the crystallization of PbI2 in dimethylformamide (DMF) by additional solvent of dimethyl sulfoxide (DMSO), which was proved to be capable of coordinating with PbI2 by coordinate covalent bond. The obtained PbI2(DMSO)x (0 ≤ x ≤ 1.86) complexes tend to be closely packed by means of intermolecular self-assembly. Afterward, an intramolecular exchange of DMSO with CH3NH3I (MAI) enabled the complexes to deform their shape and finally to reorganize to be an ultraflat and dense thin film of CH3NH3PbI3. The controllable grain morphology of perovskite thin film allows obtaining a power conversion efficiency (PCE) above 17% and a stabilized power output above 16% within 240 s by controlling DMSO species in the complex-precursor system (CPS). The present study gives a reproductive and facile strategy toward high quality of perovskite thin films and efficient solar cells.