Transparency has never been integrated into freestanding flexible graphene paper (FF-GP), although FF-GP has been discussed extensively, because a thin transparent graphene sheet will fracture easily when the template or substrate is removed using traditional methods. Here, transparent FF-GP (FFT-GP) was developed using NaCl as the template and was applied in transparent and stretchable supercapacitors. The capacitance was improved by nearly 1000-fold compared with that of the laminated or wrinkled chemical vapor deposition graphene-film-based supercapacitors.

No abstract

New layered SnS2 nanosheet arrays consisting of 1–5 atomic layers were synthesized directly on Sn foil as both the tin source and the metal current collector substrates by a simple biomolecule-assisted method. It is found that SnS2 nanosheets synthesized have excellent photoelectric applications, such as on lithium ion batteries, and photocatalytic, field emission, and photoconductive properties. Cyclic voltammetry and discharge and charge behaviors of the atomic SnS2 nanosheets were examined, and it shows that the average discharge capacity in 1050 mAh/g is much larger than the theoretical capacity at the 1C rate. The photocatalytic action driven by solar light is quite quick, and the degradation rate of RhB is 90%, only irradiated for 20 min when the content of SnS2 nanosheets is 0.4 g/L. The response of the SnS2 device to the incidence UV light is very fast and shows excellent photosensitivity and stability. In addition, field emission properties of SnS2 nanosheets were also researched, and we found that the turn-on field for SnS2 is 6.9 V/μm, which lowered ever reported values. The enhanced photoelectric properties are likely to originate in a graphene-like structure. Thus, graphene-like SnS2 materials are promising candidates in the photoelectric field.

Molybdenum disulfide (MoS2) has attracted extensive attention as a non-noble metal electrocatalyst for hydrogen evolution reaction (HER). Controlling the skeleton structure at the nanoscale is paramount to increase the number of active sites at the surface. However, hydrothermal synthesis favors the presence of the basal plane, limiting the efficiency of catalytic reaction. In this work, perfect hollow MoS2 microspheres capped by hollow MoS2 nanospheres (hH-MoS2) were obtained for the first time, which creates an opportunity for improving the HER electrocatalytic performance. Benefiting from the controllable hollow skeleton structure and large exposed edge sites, high-efficiency HER activity was obtained for stacked MoS2 thin shells with a mild degree of disorder, proving the presence of rich active sites and the validity of the combined structure. In general, the obtained hollow micro/nano MoS2 nanomaterial exhibits optimized electrocatalytic activity for HER with onset overpotential as low as 112 mV, low Tafel slope of 74 mV decade(-1), high current density of 10 mA cm(-2) at η = 214 mV, and high TOF of 0.11 H2 s(-1) per active site at η = 200 mV.

Currently, the application of calcium metal anodes is challenged by rapidly degenerated plating/stripping electrochemistry without suitable solid electrolyte interphases (SEIs) capable of fast Ca2+ transport kinetics and superior ability to resist anion oxidation. Here, through in situ evolved Na/Ca hybrid SEIs, symmetrical Ca//Ca batteries readily remain stable for more than 1000 h deposition–dissolution cycles (versus less than 60 h for those with pure Ca SEIs under the same condition). Coupled with a specially designed freestanding lattice‐expanded graphitic carbon fiber membrane and tailored operation voltages, the proof‐of‐concept Ca‐metal batteries reversibly run for almost 1900 cycles with ≈83% capacity retention and a high average discharge voltage of 3.16 V. The good performance not only benefits from the stable SEIs at the Ca metal surface which affords free Ca2+ transports and prohibits out‐of‐control fluridation of Ca (forming CaF2 ion‐/electron‐insulating layer) but is also attributed to reversible relay insertion/extraction electrochemistry in the cathode. This work sheds new light on durable metal battery technology.

A novel nanostructure comprised of Sb2O3/Sb@graphene NPs anchored on a carbon sheet network is reported, with excellent cycling stability, a long cycle life and a good rate capability as a sodium ion battery anode.

No abstract

A solid electrolyte interphase (SEI)‐free surface and fully reversible conversion are simultaneously realized in the Li‐ion storage of a specially designed ZnO porous nanocomposite with in situ surfaces/interfaces organic encapsulation for the first time. The built‐in oxygen‐ and/or moisture‐isolating organic layer of subangstrom thickness not only avoids the SEI formation, but also guarantees monodisperse and ultrasmall dimensions of ZnO nanocrystals, which are crucial for the high initial Coulombic efficiency (ICE) and fully reversible conversion. Benefiting from the high ICE up to 91.4%, stable long‐term cyclibility (95% capacity retention at 1 A g−1 after 1400 cycles), and no sacrificing Li‐ion storage capability (868 mAh g−1 at 0.1 A g−1), the ZnO nanocomposite demonstrates the highest initial Li‐ion utilization efficiency (ILUE, ≈85.4%) among previous transition metal oxide–based full cells.