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The rapid development of flexible and wearable electronics calls for advanced batteries with high safety, long cycling stability, and low cost. Aqueous Zn metal batteries (ZMBs) are some of the most promising candidates. The main challenges are the water-induced parasitic reactions (corrosion and passivation) and dendrite-driven battery failure in traditional liquid electrolytes. Developing new electrolyte systems is critical to overcoming these issues. Herein, an ultrastrong self-standing gelatin-based solid-state electrolyte (GSE) formed by strong hydrophobic interaction between gelatin molecule chains is first introduced for stable solid-state ZMBs. The GSEs prepared by a facile soaking strategy contain much less free water compared to conventional electrolyte systems and exhibit the highest fracture tensile strength of 2.78 MPa among the reported self-standing single-component solid-state electrolytes for ZMBs, which effectively inhibit the corrosion/passivation reaction and enable the Zn/Zn symmetric cells to stably cycle at hitherto the highest current density of 5 mA cm−2 with record high cumulative plating/stripping capacity. Meanwhile, the solid-state Zn/MnO2 full cell can deliver a high reversible specific capacity of 285 mA h g−1, superior cycling stability (90% capacity retention/500 cycles), and excellent safety under extreme working circumstances. The impressive performance sheds light on the design and applications of robust solid-state electrolytes for ZMBs. [ABSTRACT FROM AUTHOR]

The boom of flexible and wearable electronic devices boosts the development of flexible batteries with high safety and stability. However, traditional lithium-ion batteries dominating portable energy storage devices are significantly restricted by their intrinsic safety hazards. Herein we report a solid-state battery based on a self-standing gelatin-based hydrogel electrolyte (GHE), whose high ionic conductivity, robust mechanical strength, and intimate contact with electrodes enable the Zn metal anode and LiMn2O4 cathode to reversibly and stably cycle. Benefiting from the superior stability towards water, flexibility of the GHE and well-designed cell structure, the solid-state full cells of Zn/GHE/LiMn2O4 can deliver a high specific capacity of 110.2 mA h g−1 and resist cutting, soaking in water, bending, twisting and crimping. The newly developed solid-state Zn metal battery with high safety and stability sheds light on the application of rechargeable batteries in flexible and wearable devices. [ABSTRACT FROM AUTHOR]

Solar sails have many advantages over traditional chemical propulsion spacecraft, such as needlessness of fuel, high payload ratio, long service life, and great application potential in deep space exploration, interstellar voyage, and other aerospace application fields. However, the period of solar sail transfer from the initial orbit to the desired orbit is relatively long. Thus, it is necessary to optimize the transfer trajectory of solar sail according to specific tasks. The hp-adaptive pseudospectral method combines the global pseudospectral method with the finite element method, which adopts double layer optimization strategy to solve the optimal control problem and has higher computational efficiency and accuracy than the traditional global pseudospectral method. In this paper, the pressure of solar light acting on the solar sail is analyzed, and the kinematic equation of the solar sail is established in polar coordinate system first; then the basic principle of the hp-adaptive pseudospectral method is introduced, and the steps of solving the transfer trajectory optimization problem by hp-adaptive pseudospectral method are proposed; finally, the trajectory optimization of the solar sail from Earth orbit to Sun-centered Mars orbit is simulated as an example to demonstrate the effectiveness of hp-adaptive pseudospectral method in the orbit transfer optimization problem of solar sail. The simulation results show that the adopted method is not sensitive to the initial values and has more reasonable distribution and less computational cost than the Gauss pseudospectral method. [ABSTRACT FROM AUTHOR]

Microwave-assisted method have been chosen to synthesize Er/Yb co-doped CaMoO upconversion luminescence nanoparticles. Microscopic morphology, microstructure and luminescence properties of the samples were characterized by Scanning electron microscopy, X-ray powder diffractions and fluorescence spectroscopy. CaMoO: Er/Yb samples were composed of many small spherical particles and size of the particle was about 100 nm. Different factors (pH, microwave time, sintering temperature) that affect luminescent properties have been studied. The fluorescence intensity of upconversion luminescence particles in acid and neutral solutions was stronger; with increasing microwave time, the fluorescence intensity increased first and then decreased, 9 min of microwave time of nanoparticles showed the strongest fluorescence intensity; as sintering temperature increased, 800 °C reached the strongest fluorescence intensity. Green emission at 532 nm (H → I) and 554 nm (S → I) can occur through a two-photon process. The current work paves the way for their potential application in optical maser. [ABSTRACT FROM AUTHOR]

Rechargeable Zn-ion batteries (ZIBs) have attracted extensive attention, but their practical application is hindered by the limited cycling life and complicated preparation process of cathode materials. Here, we develop a facile yet scalable chemical precipitation/spray-granulation combined methodology for the fabrication of α-MnO 2 nanofibers/carbon nanotubes hierarchically assembled microspheres (α-MnO 2 /CNT HMs) as the cathode material for aqueous ZIBs. The α-MnO 2 evenly anchoring to the CNTs-based framework shows significantly increased tap density compared with pristine α-MnO 2 , which can effectively enhance the electrochemical stability. Owing to the synergistic merits of highly conductive carbon nanotubes network and α-MnO 2 nanofibers with desirable structure features, within our knowledge, the highest areal energy density of 0.98 Wh cm−2 at 0.2 A g−1 and the record cycling stability with 96% capacity retention over 10000 cycles at 3 A g−1 among the reported cathodes for ZIBs are achieved. Zn2+ and H+ co-insertion reaction mechanism with high reversibility is further revealed. Fast kinetic of the H+ insertion/extraction process renders the cell excellent cycling stability. Facile preparation of nanofibrous α-MnO 2 based micro-composite, cost benefit of the source materials, and the superior battery performance provide new approaches for the practical applications of ZIBs. Image 1 • α-MnO 2 /CNT HMs is fabricated by a facile precipitation/spray-granulation method. • Highly conductive CNTs network and α-MnO 2 nanofibers provide synergistic merits. • It delivers the highest areal energy density of 0.98 Wh cm−2 at 0.67 W cm−2. • The record cycling stability with 96% capacity retention over 10000 cycles is achieved. [ABSTRACT FROM AUTHOR]

The Na-O2 battery system is attracting increasing attention due to its superiority in specific capacity and cost. However, its practical implementation is hindered by many issues, such as high charge-discharge overpotential, limited cycling life, and poor reversibility, all of which result from the mediocre O2 electrode. Herein, to surmount these critical challenges, hierarchical Co3O4@MnCo2O4.5 nanocubes (h-Co3O4@MnCo2O4.5 Ns) with a yolk-shell structure are designed for the first time as the novel O2 electrode. h-Co3O4@MnCo2O4.5 Ns are synthesized from a metal-organic framework via a template-assisted method, which is demonstrated to be helpful in creating a high specific surface area of 130.4 m2 g-1, a hierarchical macro- and mesoporous structure, and synergistic yolk-shelled Co3O4@MnCo2O4.5 active sites. These unique structural properties endow h-Co3O4@MnCo2O4.5 Ns with remarkably enhanced electrocatalytic activity towards both the ORR and OER. The Na-O2 battery based on h-Co3O4@MnCo2O4.5 Ns displays an ultrahigh initial discharge capacity of 8400 mA h g-1, ultralow charge-discharge overpotential of 0.45 V, long cycling life of 135 cycles, and excellent rate capability.

In this study Er³⁺ doped CaMoO₄ (CaMoO₄:Er³⁺), and Er³⁺/Yb³⁺-co-doped CaMoO₄ (CaMoO₄:Er³⁺Yb³⁺) nanoparticles have been synthesized by the microwave-assisted metathetic method. Er³⁺/Yb³⁺ co-doped CaMoO₄ nanoparticles sintered at 600 °C showed the strongest photoluminescence intensity, and crystallized well. At the excitation of 980 nm, the CaMoO₄ nanoparticles show the strongest green emission at the 520 nm and 550 nm emission bands. Moreover, the green light produced has a better color purity.