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A NiS-MoS2@N-doped carbon (HH-NMS@NC) composite is fabricated by sacrificial template, self-assembly, and post-sulfidation strategy. The NiS nanoparticles are uniformly anchored on MoS2/NC nanosheets to construct a hierarchical hollow structure, which can shorten the electrons/ions transport pathway, facilitate electrolyte infiltration, and thus enhance the electrochemical kinetics. Furthermore, the N-doped carbon coating can significantly improve the electrical conductivity and prevent the electrode pulverization during cycling due to effectively restricting the large volume change of metal sulfides. In addition, mixed metal sulfides show an intrinsic synergistic effect for enhancing sodium storage compared to single-component metal sulfides. Given these advantages, HH-NMS@NC as anode for Na-ion batteries exhibits enhanced electrochemical performance. Specifically, HH-NMS@NC can deliver an initial discharge of 488 mAh g−1 and 311 mAh g−1 retained after 700 cycles at 1 A g−1, corresponding to 0.064% capacity decay per cycle. Furthermore, it shows a superior rate capability of 377 mAh g−1 at 8 A g−1.

Lithium-sulfur batteries have several disadvantages, such as intrinsic insulation of sulfur and Li 2 S, large volume expansion, and inevitable shuttle effect, which lead to low utilization of active materials and rapid capacity decay. Herein, leaf-like interconnected network structure of MWCNT/Co 9 S 8 was synthesized by a simple hydrothermal method. The MWCNT/Co 9 S 8 /S delivers a high specific capacity and good cycling stability. The initial discharge capacity of MWCNT/Co 9 S 8 /S is 1124 mAh g −1 and retains at 503 mAh g −1 after 100 cycles at 0.1 C. The improved electrochemical performance of MWCNT/Co 9 S 8 /S could be attributed to the interconnected network MWCNT and polar Co 9 S 8 . As conductive skeletons, the interconnected network structure of MWCNT midribs provide fast conduction paths for electron and additional space for volume expansion of sulfur. Furthermore, sulfur particles well-distributed on the MWCNT/Co 9 S 8 scaffold facilitate Li + ions storage and release for energy delivery, which is beneficial to excellent activation of sulfur and high rate capacity. In addition, the polar Co 9 S 8 leaves provide strong binding sites to trap polar polysulfide intermediates, which can suppress the shuttle effect effectively.

A hydrothermal strategy is developed to realize the controllable synthesis of hexagonal bipyramid α-Fe2O3 microcrystals (HB-α-Fe2O3 MCs) using FeOOH nanorods as precursor. Based on the SEM, TEM and BET analysis, such HB-α-Fe2O3 MCs have a perfect hexagonal bi-pyramid structure with the specific surface area of 78.2 m2 g–1. Formation mechanism of HB-α-Fe2O3 MCs is tentatively proposed by comparative structure-evolution investigations. By virtue of their structural advantages, HB-α-Fe2O3 MCs served as a gas sensor exhibit remarkable sensor response, selectivity, and response/recovery towards ethanol gas. All these impressive performances indicate their appealing application in advanced gas sensors. This well-controllable hexagonal bipyramid microcrystals are opening up an unusual way to fabricate advanced electrodes for sensor, catalyst, and energy-related applications.

Recent researches demonstrate that functional materials (such as heteroatom doped carbon and metal oxides) as sulfur host can chemically adsorb lithium polysulfides, thereby alleviating the shuttle effect of Li-S batteries (LSBs). Herein, a hierarchical core-shell nanocomposites are rationally designed for enhancing the cycle performance of the sulfur cathode, which is constructed by ZIF-8 derived carbon core and hierarchical Mn3O4/N-doped carbon shell (ZPC@HMn3O4/NC). The ZPC core with highly porous structure can provide sufficient space for sulfur loading and physical adsorption of the polysulfides during cycling. Moreover, the hierarchical Mn3O4/NC shell play a dual role in physical restricting and offering strong chemical adsorption of polysulfides. As a result, the ZPC@HMn3O4/NC as sulfur host exhibits superior electrochemical performance. Specifically, ZPC@Mn3O4-NPC/S cathode with 71.5 wt% sulfur content shows an initial capacity of 1236 mAh g−1 at 0.1 C, an excellent rate capability of 430 mAh g−1 at 8 C and a long-term cycling performance of 301 mAh g−1 after 1000 cycles at 5 C.

A nanocomposite consists of N-doped carbon nanofibers and Co-containing MOFs (ZIF-67) derived ultrasmall Co3O4 nanoparticles (NCNF/Z-Co3O4 NPs) is prepared via introducing electrospun and coordination-assisted assembly strategies. In this design, Co2+ in the electrospun PAN-Co(Ac)2 nanofibers coordinate with 2-Methylimidazole (2-MeIM) to form ZIF-67 nanocrystals and further convert into ultrasmall Co3O4 NPs dispersed in the carbon fibers matrix. The carbon nanofibers serve as a highly conductive framework interconnect and confine the Co3O4 NPs, thereby improving the electrical conductivity and buffering the volume expansion of Co3O4. In addition, both N-doping originated from ZIF-67 and PAN, as well as the ultrasmall particle size of Co3O4 emerge the surface or near-surface redox reactions, enhancing pseudocapacitive contributions and rendering fast kinetics. Due to these advantages, NCNF/Z-Co3O4 NPs anode shows enhanced lithium storage properties (1189 mAh g−1at 0.1 A g−1, 407 mAh g−1 at 1 A g−1 after 850 cycles and 329 mAh g−1 at 8 A g−1).

An innovative and controlled strategy has been proposed to design tin disulfide (SnS2) nanosheet coating on nanostructure hollow sphere of ternary spinel sulfide (NiCo2S4) composites smart architecture as anodes (NiCo2S4/SnS2) for lithium-ion batteries (LIBs) by a facile template-free hydrothermal method. The NiCo2S4/SnS2 electrode showed good electrochemical performances, for instance, high reversible capacity (1260 mA h g−1@0.1 A g−1), favorable rate capability and good cycles stability (627 mA h g−1 @0.5 A g−1 after 300 cycles), which is ascribed to smart architecture hollow structure, good electrical conductivity and contribution of synergistic effect. The mechanism of lithiation and delithiation process in NiCo2S4/SnS2 composite electrodes was further shed light upon. Moreover, the advanced full batteries have been assembled by combing NiCo2S4/SnS2 anodes with commercial NMC111 cathodes, which presented good cycle stability and potential promising application. Our work provides novel way to design multifunction metal sulfides with desirable architecture and superior property in energy storage area.

Vanadium nitride is highly desirable for their good electrochemical performance and wide work potential window, but they are cramped practical applications in supercapacitors due to poor cycling stability. Herein a combined strategy is exploited to fabricate coralloid-like nanostructure vanadium nitride/carbon (VN/C) via a facile hydrothermal method. The structural characterization displayed that nano-VN was uniformly distributed in the carbon scaffold materials to improve the electrode behavior. Those composites exhibited a wide voltage window of −1.1 to 0 V with a specific capacitance of 385 F g−1 at 1 A g−1, and exceptional cycling stability (88.9% retention after 10000 cycles). The two-electrode system based on VN/C electrodes obtains a high energy density of 24.2 Wh kg−1 at a power density of 1050 W kg−1. The device also shows perfect cycling stability with 93.3% capacitance retention after 10000 cycles. The coralloid-like VN/C electrode materials can be used in practical applications of the high-performance energy storage device.