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This review provides insight into various nanostructures designed by spray pyrolysis and their applications in energy storage and conversion.

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The further development of lithium-sulfur (Li-S) batteries is limited by the fact that the soluble polysulfide leads to the shuttle effect, thereby reducing the cycle stability and cycle life of the batteries. To address this issue, here a thin and lightweight (8 μm and 0.24 mg cm) reduced graphene oxide@MoS (rGO@MoS) interlayer between the cathode and the commercial separator is developed as a polysulfide barrier. The rGO plays the roles of both a polysulfide physical barrier and an additional current collector, while MoS has a high chemical adsorption for polysulfides. The experiments demonstrate that the Li-S cell constructed with an rGO@MoS-coated separator shows a high reversible capacity of 1122 mAh g at 0.2 C, a low capacity fading rate of 0.116% for 500 cycles at 1 C, and an outstanding rate performance (615 mAh g at 2 C). Such an interlayer is expected to be ideal for lithium-sulfur battery applications because of its excellent electrochemical performance and simple synthesis process.

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Mixed transition metal oxides with hierarchical, porous structures, constructed from interconnected nano-building blocks, are considered promising positive electrodes for high-performance hybrid supercapacitors. Here we report our findings in design, fabrication, and characterization of 3D hierarchical, porous quaternary zinc-nickel-aluminum-cobalt oxide (ZNACO) architectures assembled from well-aligned nanosheets grown directly on nickel foam using a facile and scalable chemical bath deposition process followed by calcination. When tested as a binder-free electrode in a 3-electrode configuration, the ZNACO display high specific capacity (839.2 Cg -1 at 1 Ag -1 ) and outstanding rate capability (~82% capacity retention from 1 Ag -1 to 20 Ag -1 ), superior to those of binary-component NiCo 2 O 4 and ZnCo 2 O 4 as well as single-component Co 3 O 4 electrode. More remarkably, a hybrid supercapacitor consisting of an as-fabricated ZNACO positive electrode and an activated carbon negative electrode exhibits a high energy density of 72.4 Wh kg -1 at a power density of 533 W kg -1 while maintaining excellent cycling stability ( ~90% capacitance retention after 10,000 cycles at 10 Ag -1 ), demonstrating a promising potential for development of high-performance hybrid supercapacitors. Further, the unique electrode architecture is also applicable to other electrochemical systems such as batteries, fuel cells, and membrane reactors.

Lithium-ion capacitors have attracted tremendous attention among various electrochemical energy storage systems, benefitting from the merits of high energy density, high power output, long cycle life and favorable chemical stability.

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