We report the effort in designing layered SnS nanocrystals decorated on nitrogen and sulfur dual-doped graphene aerogels (SnS@N,S-GA) as anode material of SIBs. The optimized mass loading of SnS along with the addition of nitrogen and sulfur on the surface of GAs results in enhanced electrochemical performance of SnS@N,S-GA composite. In particular, the introduction of nitrogen and sulfur heteroatoms could provide more active sites and good accessibility for Na ions. Moreover, the incorporation of the stable SnS crystal structure within the anode results in the superior discharge capacity of 527 mAh g under a current density of 20 mA g upon 50 cycles. It maintains 340 mAh g even the current density is increased to 800 mA g. Aiming to further systematically study mechanism of composite with improved SIB performance, we construct the corresponding models based on experimental data and conduct first-principles calculations. The calculated results indicate the sulfur atoms doped in GAs show a strong bridging effect with the SnS nanocrystals, contributing to build robust architecture for electrode. Simultaneously, heteroatom dual doping of GAs shows the imperative function for improved electrical conductivity. Herein, first-principles calculations present a theoretical explanation for outstanding cycling properties of SnS@N,S-GA composite.

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A novel electrochemical platform was designed by combining the biocompatibility of single-stranded DNA (ss-DNA) and the excellent conductivity of graphene (GP). This nanocomposite (denoted as ss-DNA/GP) was first used as an electrode material for the immobilization and biosensing of redox enzymes. On the basis of electrostatic interactions, horseradish peroxidase (HRP) self-assembled with ss-DNA/GP on the surface of a glassy carbon (GC) electrode to form an HRP/ss-DNA/GP/GC electrode. UV/Vis and FTIR spectra were used to monitor the assembly process and indicated that the immobilized HRP on the ss-DNA/GP matrix retained its native structure well. A pair of stable and well-defined redox peaks of HRP with a formal potential of about -0.26 V (vs. Ag/AgCl) in a pH 7.0 phosphate buffer solution were obtained at the HRP/ss-DNA/GP/GC electrode; this demonstrates direct electron transfer between the immobilized HRP and the electrode. In addition, the modified electrode showed good electrocatalytic performance towards H(2)O(2) with high sensitivity, wide linear range, and good stability. Accordingly, the ss-DNA/GP nanocomposite provides a novel and efficient platform for the immobilized redox enzyme to realize direct electrochemistry and has a promising application in the fabrication of third-generation electrochemical biosensors.

A novel high-voltage cathode material Na6Fe5(SO4)8 (NFS) is successfully prepared for sodium-ion batteries for the first time. It is found that the NFS cathode shows a high working voltage of 3.7 V, together with an attractive energy density approaching 450 W h kg−1. And, based on an NFS@5%CNTs cathode and hard carbon (HC) anode, a full NFS@5%CNTs//HC cell can deliver an impressive energy density approaching 350 W h kg−1 and excellent cycling stability over 1000 cycles at 2C.

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Ionic liquid functionalized Janus nanosheets are synthesized by selective treatment of the imidazolin terminated side of Janus nanosheets while the other side is preserved. The Janus performance of the nanosheets and thus emulsion stability are reversibly triggered by anion exchange.