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Based on the Lennard-Jones potential function, a theoretical model of atoms/ions interaction with finite-size (doped) graphene is presented to investigate the mechanical behaviors of atoms/ions adsorption and migration on the surface of finite-size boron, nitrogen and boron nitride doped graphene. The results show that boron, nitrogen and boron nitride doping can change the interaction between atoms/ions and graphene, and the type, position and domain size of doping elements have significant effects on the adsorption sites and adsorption energy of atoms/ions. The stable adsorption sites, adsorption heights and adsorption energy of atoms/ions on the surface of doped graphene can be controlled by regulating the doping elements. Meanwhile, boron, nitrogen and boron nitride doping can affect the energy period and energy barrier of atoms/ions migration on graphene surface. The proper design of boron, nitrogen and boron nitride doping position, size and distribution can effectively control the atom/ion migration behavior on graphene surface. This research work can provide a theoretical reference for atoms/ions carriers, molecular sieves and ion battery electrodes based on doped graphene and graphene heterostructures. [ABSTRACT FROM AUTHOR]

Advanced hierarchical hybrid nanostructures of polar, conductive and catalytic chemical traps/carbon with rationally tailored components, structures, and chemistries are important in determining the performance of lithium-sulfur (Li–S) batteries. Herein we propose a facile strategy to prepare 3D-structured CNF@graphene-CoSe (CNF@G L -CoSe) cable/sheath heterostructure with the in-situ formed CoSe as a catalyst for graphene-like carbon growth and Se as a catalyst promoter. The architecture integrates high electrical conductivity, effective ion transport, notable polysulfide entrapment, and polysulfide redox kinetics, availing lithium/sulfur conversion when applied as an interlayer in a Li–S battery. As expected, the battery delivered a low decay of 0.053% per cycle over 700 cycles at 1 C. The capacity even remained 649.4 and 524.5 mA h g−1 at 4 and 6 C, respectively. Furthermore, an areal capacity of about 3 mA h cm−2 at 0.1 C after long-term tests can still maintain with sulfur loading of 4.5 mg cm−2. A facile effective strategy to prepare 3D-structured CNF@graphene-CoSe cable/sheath heterostructure with the in situ formed CoSe as a catalyst for graphene-like carbon growth and Se as a catalyst promoter, achieving significant enhancement in electrochemical performance of Li–S batteries. [Display omitted] • In situ constructing CNF@graphene-CoSe cable/sheath heterostructure. • CoSe catalyzes the growth of graphene sheath and Se as a catalyst promoter. • Synergism of conductivity, absorption and catalysis. • Enabling excellent performance as an interlayer. [ABSTRACT FROM AUTHOR]