Three-dimensional skeleton-structured assemblies of graphene sheets decorated with SnO nanocrystals are fabricated via a facile and large-scalable spray-drying-induced assembly process with commercial graphene oxide and SnO sol as precursors. The influences of different parameters on the morphology, composition, structure, and electrochemical performances of the skeleton-structured SnO/graphene composite spheres are studied by XRD, TGA, SEM, TEM, Raman spectroscopy, and N adsorption-desorption techniques. Electrochemical properties of the composite spheres as the anode electrode for lithium-ion batteries are evaluated. After 120 cycles under a current density of 100 mA g, the skeleton-structured SnO/graphene spheres still display a specific discharge capacity of 1140 mAh g. It is roughly 9.5 times larger than that of bare SnO clusters. It could still retain a stable specific capacity of 775 mAh g after 50 cycles under a high current density of 2000 mA g, exhibiting extraordinary rate ability. The superconductivity of the graphene skeleton provides the pathway for electron transportation. The large pore volume deduced from the skeleton structure of the SnO/graphene composite spheres increases the penetration of electrolyte and the diffusion of lithium ions and also significantly enhances the structural integrity by acting as a mechanical buffer.

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Advanced Ni//Zn batteries possess great promise that combines battery‐level energy density and capacitor‐level power density. However, the surface chemical reactivity of the cathode is generally restricted by active material utilization, leading to an insensitive edge site and unsatisfactory capacity. Herein, a simple and energy‐saving strategy is reported for manipulating the bimetallic sulfide nanointerfaces via water invoking interface corrosion to achieve a 200% increase in the capacity of electrodes. The combined action of water and oxygen causes secondary in situ growth of NiCo–OH nanosheet coating layers on the CoxNi3‐xS2 nanowalls with surface enrichment of low‐valence mixed states, which deliver remarkable reactive activity and structural stability. As a result, the 3D cathode yields an ultrahigh capacity of 2.45 mAh cm−2, higher than that of the pristine nanomaterial (1.20 mAh cm−2). The resulting Ni//Zn battery with excellent reversibility and long‐life, achieves a remarkable energy density of 4.29 mWh cm−2 (728 Wh kg−1), which is superior to most recently reported aqueous Zn‐based batteries and is even comparable to Li‐ion batteries. This work explores the interface corrosion mechanism and corrosion‐surface activity relationship, which is a powerful strategy to construct high surface electrochemical activity of metallic sulfides/phosphides for renewable energy storage devices.

Lithium-sulfur batteries have attracted increasing attention in the field of energy storage due to their advantages of high specific energy and energy density. However, there are still many difficulties in...

With the rapid development of wireless Internet services, several WLAN service providers may coexist in one public hotspot to compete for the same group of customers, leading to an inevitable price competition. The charged price and the provisioned packet loss at each provider are major factors in determining users' demands and behaviors, which in turn will affect providers' revenue and social welfare. In this paper, we set up a novel game model to analyze a duopoly price competition. We first show the users' demands are distributed between providers according to a Wardrop Equilibrium and then prove the existence of a Nash equilibrium on providers' charged prices. Through analysis, we further find that in Nash equilibrium state the social welfare is very close to its maximal value in cooperative situation. Furthermore, the providers' aggregate revenues also do not decrease when the users have high sensitivity about the charged prices. Thus the competitive duopoly WLAN market can still run in an efficient way even in the absence of complex regulation schemes.

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The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/smll.202107252. Suitable anode materials with high capacityand long cycling stability, especially capability at high current densities, are urgently needed to advance the development of potassium ion batteries (PIBs) and sodium ion batteries (SIBs). Herein, a porous Ni-doped FeSe 2 /Fe 3 Se 4 heterojunction encapsulated in Se-doped carbon (NF 11 S/C) is designed through selenization of MOFs precursor. The porous composite possesses enriched active sites and facilitates transport for both ion and electron. Ni-doping is adopted to enrich the lattice defects and active sites. The Se-C bond and carbon framework endow integrity of the composite and hamper aggregation of selenide nano-particles during potassiation/de-potassiation. The NF 11 S/C exhibits exceptional rate performance and ultra-long cycling stability (177.3 mA h g −1 after 3050 cycles at 2 A g −1 for PIBs and 208.8 mA h g −1 after 2000 cycles at 8 A g −1 for SIBs). The potassiation/de-potassiation mechanism is investigated via ex-situ X-ray powder diffraction, high-resolution transmission electron microscopy, X-ray photoelectron spectrocopy and Raman analysis. PTCDA//NF 11 S/C full cell stably cycles for 1200 cycles at 200 mA g −1 with a capacity of 103.7 mA h g −1 , indicating the high application potential of the electrode for highly stable rechargeable batteries.