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Background Yak (Bos grunniens) is a unique livestock animal originating from the Qinghai-Tibet Plateau in China. In the current study, we investigated the maternal genetic diversity, differentiation and phylogeny of wild yak population and four domestic yak breeds (Qinghai-Gaoyuan, Huanhu, Xueduo, and Yushu) in Qinghai, China by analyzing 166 mitochondrial cytochrome b (Cytb) gene sequence variations. Results The haplotype and nucleotide diversities of wild yak were 0.883±0.044 and 0.004±0.002, while the total haplotype and nucleotide diversities of four Qinghai domestic yak breeds were 0.646±0.040 and 0.003±0.001, respectively. Among the four Qinghai domestic yak breeds, the haplotype diversity was found to be highest in Yushu yak breed (Hd = 0.770±0.053), while the lowest was recorded in Huanhu yak breed (Hd = 0.501±0.088). Estimates of FST values showed a moderate genetic differentiation between wild yak and Huanhu yak (FST = 0.058) as well as that between Huanhu yak and Yushu yak breeds (FST = 0.052), but a weak genetic differentiation was observed between the other yak breeds/populations (-0.021＜FST＜0.037). Additionally, the clustering analysis based on RST values showed that Xueduo yak and Huanhu yak were clustered into one group, and each of the other three yak breeds/populations was separated into one group, respectively. Overall, the clustering relationship between wild yak and Yushu yak was closer. Maternal phylogenetic analysis showed that wild yak and four local yak breeds/populations in Qinghai represented in three maternal lineages (Mt-Ⅰ, Mt-Ⅱ, and Mt-Ⅲ), indicating three maternal origins in yak. Conclusion Our study would provide valuable information for the conservation and utilization of wild yak and Qinghai domestic yak breeds.

Alkaline aqueous batteries such as the Zn||Ni batteries have attracted substantial interests due to their merits of high energy density, high safety and low cost. However, the freeze of aqueous electrolyte and the poor cycling stability in alkaline condition have hindered their operation in subzero conditions. Herein, we construct a stable aqueous electrolyte with lowest freezing point down to -90 °C by adding dimethyl sulfoxide (DMSO) as alkaline tolerant antifreezing additive into 1 M KOH solution. Meanwhile, we find the DMSO can also retard Zn anode corrosion and prevent Zn dendrite formation in alkaline condition, which enables the Zn plating/stripping over 700 h cycle at 1 mA cm

Proposed are Prussian blue analogue hosts with ordered and continuous channels, and electrocatalytic functionality with open Co and Fe species, which facilitate maximum I2 utilization efficiency and direct I2 to I- conversion kinetics of the I2 reduction reaction, and free up 1/3 I- from I3 - . Co[Co1/4 Fe3/4 (CN)6 ] exhibits a low energy barrier (0.47 kJ mol-1 ) and low Tafel slope (76.74 mV dec-1 ). Accordingly, the Co[Co1/4 Fe3/4 (CN)6 ]/I2 //Zn battery delivers a capacity of 236.8 mAh g-1 at 0.1 A g-1 and a rate performance with 151.4 mAh g-1 achieved even at 20 A g-1 . The battery delivers both high energy density and high-power density of 305.5 Wh kg-1 and 109.1 kW kg-1 , higher than I2 //Zn batteries reported to date. Furthermore, solid-state flexible batteries were constructed. A 100 mAh high capacity solid-state I2 //Zn battery is demonstrated with excellent cycling performance of 81.2 % capacity retained after 400 cycles.

The consensus practice in research of high energy density energy storage devices is to simultaneously achieve high areal capacity and high intrinsic specific capacity. Increasing the areal capacity of batteries necessitates the maximization of their mass loading. However, batteries usually deliver mass loading-dependent electrochemical performance. Take selenium (Se) cathode with a theoretically high specific capacity as an example, Se reaction kinetics, utilization and cycling lifespan seriously deteriorate with increased Se mass loading. Here, we propose an electrocatalytic Se reduction/oxidation reaction strategy to realize high-Se-loading Zn||Se batteries with fast kinetics and high Se utilization. Specifically, the synergetic effects of Cu and Co transition-metal species inside channel structure of host can effectively immobilize and catalytically convert Sen during cycling, which thus facilitates Se utilization and 6-electron (Se4+ \(\leftrightarrow\) Se2–) conversion kinetics. In particular, the Cu[Co(CN)6] host exhibits a remarkably low energy barrier (1.63 kJ·mol−1) and low Tafel slope (95.23 mV·dec−1) for the Se reduction, and highest current response for Se oxidation. Accordingly, the Zn battery employing Se-in-Cu[Co(CN)6] cathode delivers a capacity of 664.7 mAh⋅g−1 at 0.2 A⋅g−1, an excellent rate capability with 430.6 mAh⋅g−1 achieved even at 10 A⋅g−1, and long-cyclic life over 6000 cycles with 90.6% capacity retention. Furthermore, an A-h-level (~1350 mAh) Zn||Se pouch-type battery with high Se loading (~12.3 mg(Se)⋅cm−2) shows a high Se utilization of 3.3 % and outstanding cyclic stability with 9.4 % initial capacity retained after 400 cycles at exceedin 98 % Coulombic efficiency.

DRT is a customized public transport system with precisely matching of supply and demand and efficient utilization of supply. In this paper, the digital twin model is introduced to construct the individual trip chain and the bus operation chain respectively, as well as realize the calculation and feedback of the whole process of DRT service. In addition, this paper also carries out equivalent solution for the key link of the whole process calculation of DRT service, bus transit between stations, which ensures the accuracy of the model. Finally, through the case analysis, it is verified that the calculation of the whole process of DRT service plays an important role in the evaluation and optimization of DRT service.

Color-tunable semiconductor quantum dots (QDs) are highly attractive for a wide range of applications including imaging, sensing, and lighting. Herein, we reported a facile synthesis of copper-doped zinc sulfide quantum dots (ZnS:Cu QDs) with tunable emission colors, using a microwave-assisted one-pot reaction. 3-mercaptopropionic acid (MPA) was used as a stabilizer agent and sulfide source for the formation of ZnS:Cu QDs. The photoluminescence of ZnS:Cu QDs showed a clear red-shift as increasing Cu concentration, which can be controlled by microwave irradiation time. As increasing the irradiation time, the emission color (peak) of ZnS:Cu QDs changed from blue (500 nm) to green (540 nm), yellow (580 nm), and to orange-red (595 nm). The obtained ZnS:Cu QDs were highly luminescent, as evidenced by their high quantum yields. The potential utility of ZnS:Cu QDs as a novel lighting source was demonstrated in a near-UV chip-based white light-emitting diode.

High electrochemical performance energy storage devices coupled with low cost and high safety operation are in urgent need due to the increasing demand for flexible and wearable electronics. For these applications lithium-ion and sodium-ion batteries are vastly limited due to their relatively low power density and security risks. On the other hand, conventional supercapacitors are suitable for flexible and wearable electronics due to their high power density while their low energy density has hindered their wide applications. Lithium or sodium ion hybrid supercapacitors are promising energy storage devices that benefit from the combined high energy density of batteries and high power density of supercapacitors. However, the use of organic electrolytes and shortage of lithium resources are expected to limit their widespread commercialization for flexible and wearable electronics. Here, for the first time, we introduce a safe and flexible solid-state zinc ion hybrid supercapacitor (ZHS) based on co-polymer derived hollow carbon spheres (HCSs) as the cathode, polyacrylamide (PAM) hydrogel as the electrolyte and Zn deposited on carbon cloth as the anode. Owing to the high surface area of the HCSs and the hollow structure which improves the ion adsorption and desorption kinetics of the cathode, the flexible solid-state ZHS delivers a highest capacity of 86.8 mA h g−1 and a maximum energy density of 59.7 W h kg−1 with a power density of 447.8 W kg−1. Besides, it displays excellent cycling stability with 98% capacity retention over 15 000 cycles at a current density of 1.0 A g−1. Moreover, the solid-state ZHS is flexible enough to sustain various deformations including squeezing, twisting and folding due to the use of flexible electrodes and electrolytes. Our study unveils a pioneering flexible solid-state ZHS with high safety, which is a promising candidate for flexible and wearable energy storage devices.

Zn batteries are usually considered as safe aqueous systems that are promising for flexible batteries. On the other hand, any liquids, including water, being encapsulated in a deformable battery may result in problems. Developing completely liquid-free all-solid-state Zn batteries needs high-quality solid-state electrolytes (SSEs). Herein, we demonstrate in situ polymerized amorphous solid poly(1,3-dioxolane) electrolytes, which show high Zn ion conductivity of 19.6 mS cm-1 at room temperature, low interfacial impedance, highly reversible Zn plating/stripping over 1800 h cycles, uniform and dendrite-free Zn deposition, and non-dry properties. The in-plane interdigital-structure device with the electrolyte completely exposed to the open atmosphere can be operated stably for over 30 days almost without weight loss or electrochemical performance decay. Furthermore, the sandwich-structure device can normally operate over 40 min under exposure to fire. Meanwhile, the interfacial impedance and the capacity using in situ-formed solid polymer electrolytes (SPEs) remain almost unchanged after various bending tests, a key criterion for flexible/wearable devices. Our study demonstrates an approach for SSEs that fulfill the requirement of no liquid and mechanical robustness for practical solid-state Zn batteries.

Two-dimensional (2D) nanomaterials have become a new class of microwave absorption (MA) materials due to their high specific surface area and peculiar electronic properties. In this study, MoS 2 /graphene 2D hybrid nanosheets with isomorphic hetero-structures are prepared by liquid exfoliation and hydrothermal reaction. Their chemical composition and morphology are characterized and their MA properties are also investigated comprehensively. The minimum reflection loss (RL) value of an absorber containing wax and 20 wt% MoS 2 /graphene hybrid nanosheets (MoS 2 /GN) is −55.3 dB at a thickness of only 1.6 mm. The largest effective absorption bandwidth is up to 5.6 GHz for an absorber containing wax and 15 wt% MoS 2 /GN at a thickness of 2.2 mm. The enhanced MA performance of MoS 2 /GN is attributed to the high electrical conductivity of graphene and the multiple MoS 2 /graphene interfaces in the heterogeneous structures. The results suggest that those light-weight MoS 2 /graphene hybrid nanosheets are very promising materials for electromagnetic wave absorbing, which can exhibit broad effective absorption bandwidth in the absorber containing low loadings of MA materials at a small thickness. Besides, the facile preparation of MoS 2 /graphene hybrid nanosheets reported in this work provides a feasible and effective approach in the synthesis of high-performance 2D MA nanomaterials.

Although both are based on Zn, Zn–air batteries and Zn–ion batteries are good at energy density and power density, respectively. Here, we adopted Ar–plasma to engrave a cobalt oxide with abundant oxygen vacancies (denoted as Co3O4–x). The introduction of oxygen vacancies to cobalt oxide not only promotes its reversible Co–O ↔ Co–O–OH redox reaction but also leads to good oxygen reduction reaction and oxygen evolution (ORR/OER) performance (a half-wave potential of 0.84 V, four-electron transfer process for ORR, and 330 mV overpotential, 58 mV·dec–1 Tafel slope for OER). We then constructed a battery system based on both Zn–Co3O4–x and Zn–air electrochemical reactions. The hybrid battery reveals both a high-power density of 3200 W·kg–1 and high-energy density of 1060 Wh·kg–1. Furthermore, the developed flexible solid-state hybrid batterydemonstrates good waterproof and washable ability (99.2% capacity retention of after 20 h water soaking test and 93.2% capacity retention after 1 h washing test). Interesti...

The exploitation of a high-efficient, low-cost, and stable non-noble-metal-based catalyst with oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) simultaneously, as air electrode material for a rechargeable zinc–air battery is significantly crucial. Meanwhile, the compressible flexibility of a battery is the prerequisite of wearable or/and portable electronics. Herein, we present a strategy via single-site dispersion of an Fe–Nx species on a two-dimensional (2D) highly graphitic porous nitrogen-doped carbon layer to implement superior catalytic activity toward ORR/OER (with a half-wave potential of 0.86 V for ORR and an overpotential of 390 mV at 10 mA·cm–2 for OER) in an alkaline medium. Furthermore, an elastic polyacrylamide hydrogel based electrolyte with the capability to retain great elasticity even under a highly corrosive alkaline environment is utilized to develop a solid-state compressible and rechargeable zinc–air battery. The creatively developed battery has a low charge–discha...

Flexible supercapacitors with high areal capacitance are a promising approach for wearable energy-storage technology due to the limitation of the surface area of the human body (about 2 m2). Meanwhile, a tolerance to deformation and mechanic damage is critical for wearable applications. However, it is still a challenge to achieve supercapacitors with outstanding electrochemical performance and wearability, simultaneously. To solve this problem, we report high-performance, flexible, and tailorable solid-state supercapacitors enabled by Co3O4@PPy nanorod bundle arrays immobilized on carbon fiber cloth (CFC). Furthermore, a solid-state asymmetric supercapacitor was assembled using a freestanding Co3O4@PPy electrode, a freestanding porous carbon electrode, and PVA gel electrolyte. Benefiting from a 3D structure and the synergetic contribution of the Co3O4 nanorods and electrically conductive PPy layer, the Co3O4@PPy electrode and our developed supercapacitor exhibit a high areal capacitance of 6.67 F cm−2 at a current density of 2 mA cm−2, and 2.47 F cm−2 at 4 mA cm−2, respectively, as well as excellent rate capability. More importantly, the solid-state supercapacitor can be tailored into several units and various shapes. Each unit retains its original electrochemical performance. This work provides a new route to wearable energy-storage technology.

The Zn/Co3O4 battery is one of the few aqueous electrolyte batteries with a potential >2 V voltage. Unfortunately, so far, all reported Zn/Co3O4 batteries are using an alkaline electrolyte, resulting in poor cycling stability and environmental problems. Here, we report a Co(III) rich-Co3O4 nanorod material with vastly improved electrochemical kinetics. Zn/Co(III) rich-Co3O4 batteries can work well in ZnSO4 with a CoSO4 additive aqueous solution as a mild electrolyte, delivering a high voltage of 2.2 V, a capacity of 205 mA h g−1 (Co3O4) and an extreme cycling stability of 92% capacity retention even after 5000 cycles. Further mechanistic study reveals a conversion reaction between in situ formed CoO and Co3O4, which has never been observed in an alkaline Zn/Co3O4 battery. Subsequently, a flexible solid-state battery is constructed and reveals high flexibility and a high energy density of 360.8 W h kg−1 at a current density of 0.5 A g−1. Our research initiates the first Zn/Co3O4 battery working in a mild electrolyte, resulting in excellent electrochemical performance. It also indicates that the electrochemical kinetics can be effectively enhanced by fine tuning the atomic structure of electrode materials, opening a new door to improve the performance of aqueous electrolyte batteries.

Although some progress has been made in flexible supercapacitors (SCs), their high energy density, mechanical robustness, and device-level editability and programmability are still highly desirable for the development of advanced portable and miniaturized electronics, especially considering the fact that these flexible devices are likely to experience some mechanical impact and potential damage. Herein, we demonstrate the fabrication of hybrid electrodes containing self-assembled 2D metal–organic framework (MOF)/reduced graphene oxide (rGO) papers, which not only efficiently alleviate the self-restacking of rGO and the MOF but also maintain high electrical conductivity (0.32 Ω cm), excellent flexibility and mechanical properties with a Young's modulus of 34.4 GPa and a tensile strength of 89.9 MPa. In addition, a one-for-two strategy is introduced to construct two types of porous electrodes for flexible asymmetric SCs via a one MOF-derived synthesis route with simply changing metal ion precursors. As a consequence, the flexible asymmetric SCs possess a high volumetric energy density of 1.87 mW h cm−3 and an outstanding volumetric power density of 250 mW cm−3. More importantly, the all-solid-state asymmetric SCs exhibit high editability and bending-tolerance properties and perform very well under various severe service conditions, such as being seriously cut, bent, and heavily loaded. Particularly, the operations of micro-SCs with artistically designed patterns are demonstrated. Being high-strength, easily programmable and connectable in series and in parallel, the editable supercapacitor is promising for developing stylish energy storage devices to power various portable, miniaturized, and wearable devices.

Zinc-air batteries (ZABs) have the advantages of low price, environmental friendliness, and high energy density that enables great potential for the application of energy storage devices. Unfortunately, the main limitation of ZABs is the low kinetics of air cathode, including oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), making it necessary to develop catalysts with excellent performance to speed up the reaction rates and improve their efficiency. For these purposes, cobalt-based carbon has the advantages of low cost, high activity, and stability, which are suitable for oxygen electrocatalysts. In this review, the basic mechanisms of ORR and OER electrocatalysis are introduced and analyzed, and the development of cobalt-based carbon materials used as electrocatalysts in ZABs in recent years is reviewed, including cobalt oxide–based carbon, cobalt-nitrogen–doped carbon (Co–N–C), and cobalt bimetallic–based carbon. In addition, we review the use of in situ/in operando characterization techniques applied to trace the catalytic reactions. Finally, we provide an account of the current challenges and future perspectives for the design of new types of high efficiency and bifunctional electrocatalysts.

Non-wetting hole transport materials (HTMs) have great potential in facilitating large-sized perovskite crystal growth and enhancing device stability by opposing moisture ingress, However, the severe non-wetting issue limits the wide application of these materials in low-temperature solution-processed inverted planar perovskite solar cells (PVSCs), and corresponding devices are rarely reported. Here, a facile ultraviolet-ozone (UVO) modification method is demonstrated to overcome this issue. By carefully controlling the UVO modification time, the surface wettability of poly-TPD can be tuned without affecting the bulk properties of the film, hence perovskite films with desired grain size and excellent coverage can be deposited via a one-step spin-coating method. Benefiting from the high-quality perovskite, well-matched energy level alignment and hydrophobic property of poly-TPD, the resulting PVSCs show a champion power conversion efficiency of 18.19% with significantly enhanced stability as compared to the PEDOT:PSS counterparts. Moreover, the UVO modification approach also demonstrates its validity when being extended to other hydrophobic HTMs. This work not only provides a general strategy to broaden the selection pool of HTMs for solution-processed inverted planar PVSCs, but also may triggers the exploration of more advanced strategies to make non-wetting HTMs applicable in solution-processed inverted planar PVSCs.

The noninvasive and nondestructive Fourier transform infrared (FTIR) imaging and dynamic mechanical analysis (DMA) are developed in this work to evaluate the microstructure-related properties of UHMWPE/Recycled-PA6 blends. FTIR imaging which is of in-situ and visualizing capabilities is shown to be extremely valuable in determining the phase structure of a multiphase system. It is found that small quantities of the HDPE-g-MAH compatibilizer could significantly improve the miscibility of the two immiscible polymers. It is further proved that in the UHMWPE/R-PA6 blends the R-PA6 phase distributes continuously, while the UHMWPE phase disperses in a discontinuous manner. Moreover, the blends with 44 wt% R-PA6 is found to exhibit an optimal miscibility behavior. This work demonstrates that FTIR imaging is a direct method in visualizing the miscibility of polymer blends. The combined FTIR imaging and DMA testing offers a new approach for qualitative and quantitative investigations on polymer blends with complex microstructures.

Prussian blue analogs (PBAs) that can host almost all ions having been used in and potentially utilized in batteries, have been proposed as electrode materials for the largest variety of rechargeable batteries including single-valent (Li+, Na+, K+), multivalent (Zn2+, Cu2+, Fe2+, Mg2+, Ca2+, Sr2+, Ba2+, Pd2+, Al3+, Y3+) metal ion batteries and even non-metal charge carrier (H+, NH4+, H3O+) batteries. On the other hand, PBAs with three-dimensional open framework can provide highly reversible insertion/removal of ions in both aqueous and non-aqueous electrolytes. What is more, PBAs possess two active redox species for redox reactions during electrochemical charge/discharge process, potentially providing high specific capacity for batteries. However, in most cases, only one transition-metal specie is activated during charge/discharge process, together with existence of vacancies and coordinated/interstitial water molecular, leading to 50% lower electrochemical utilization of PBAs framework. In this review, we present a comprehensive overview on electrochemical redox of PBAs hosting Li+, Na+, K+, Zn2+, Cu2+, Fe2+, Mg2+, Ca2+, Sr2+, Ba2+, Pd2+, Al3+, Y3+, H+, H3O+ and NH4+ ions for rechargeable batteries, including number of redox active species, structural evolutions, output voltage, capacity delivered and cyclic stability. We also analyze the strategies and progresses in overcoming issues associated with achieving high specific capacity, high output voltage and long cyclic lifespan of batteries based on PBAs cathodes. Finally, perspectives are provided on the design requirements for future generation of PBAs electrodes, with focus on synthetic strategies, structure design, electrolyte optimization and electrochemical principle towards large-scale electric application.

The hydrogen evolution in Zn metal battery is accurately quantified by in situ battery-gas chromatography-mass analysis. The hydrogen fluxes reach 3.76 mmol h-1 cm-2 in a Zn//Zn symmetric cell in each segment, and 7.70 mmol h-1 cm-2 in a Zn//MnO2 full cell. Then, a highly electronically insulating (0.11 mS cm-1 ) but highly Zn2+ ion conductive (80.2 mS cm-1 ) ZnF2 solid ion conductor with high Zn2+ transfer number (0.65) is constructed to isolate Zn metal from liquid electrolyte, which not only prohibits over 99.2% parasitic hydrogen evolution but also guides uniform Zn electrodeposition. Precisely quantitated, the Zn@ZnF2 //Zn@ZnF2 cell only produces 0.02 mmol h-1 cm-2 of hydrogen (0.53% of the Zn//Zn cell). Encouragingly, a high-areal-capacity Zn@ZnF2 //MnO2 (≈3.2 mAh cm-2 ) full cell only produces maximum hydrogen flux of 0.06 mmol h-1 cm-2 (0.78% of the Zn//Zn cell) at the fully charging state. Meanwhile, Zn@ZnF2 //Zn@ZnF2 symmetric cell exhibits excellent stability under ultrahigh current density and areal capacity (10 mA cm-2 , 10 mAh cm-2 ) over 590 h (285 cycles), which far outperforms all reported Zn metal anodes in aqueous systems. In light of the superior Zn@ZnF2 anode, the high-areal-capacity aqueous Zn@ZnF2 //MnO2 batteries (≈3.2 mAh cm-2 ) shows remarkable cycling stability over 1000 cycles with 93.63% capacity retained at ≈100% Coulombic efficiency.

An ionic-liquid-based Zn salt electrolyte is demonstrated to be an effective route to solve both the side-reaction of the hydrogen evolution reaction (HER) and Zn-dendrite growth in Zn-ion batteries. The developed electrolyte enables hydrogen-free, dendrite-free Zn plating/stripping over 1500 h cycle (3000 cycles) at 2 mA cm-2 with nearly 100% coulombic efficiency. Meanwhile, the oxygen-induced corrosion and passivation are also effectively suppressed. These features bring Zn-ion batteries an unprecedented long lifespan over 40 000 cycles at 4 A g-1 and high voltage of 2.05 V with a cobalt hexacyanoferrate cathode. Furthermore, a 28.6 µm thick solid polymer electrolyte of a poly(vinylidene fluoride-hexafluoropropylene) film filled with poly(ethylene oxide)/ionic-liquid-based Zn salt is constructed to build an all-solid-state Zn-ion battery. The all-solid-state Zn-ion batteries show excellent cycling performance of 30 000 cycles at 2 A g-1 at room temperature and withstand high temperature up to 70 °C, low temperature to -20 °C, as well as abuse test of bending deformation up to 150° for 100 cycles and eight times cutting. This is the first demonstration of an all-solid-state Zn-ion battery based on a newly developed electrolyte, which meanwhile solves the deep-seated hydrogen evolution and dendrite growth problem in traditional Zn-ion batteries.