Rechargeable zinc–air batteries show great potential in applications such as electric vehicles and wearable devices, especially for the flexible design. And the challenges and functional materials for each component are provided and discussed from air electrode, solid-state electrolyte to zinc anode, with perspectives of research directions.

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As representative two-dimensional (2D) materials, layered double hydroxides (LDHs) have received increasing attention in electrochemical energy storage and conversion because of the facile tunability between their composition and morphology. The high dispersion of active species in layered arrays, the simple exfoliation into monolayer nanosheets and chemical modification offer the LDHs an opportunity as active electrode materials in electrochemical capacitors (ECs). LDHs are favourable in providing large specific surface areas, good transport features as well as attractive physicochemical properties. In this review, our purpose is to provide a detailed summary of recent developments in the synthesis and electrochemical performance of the LDHs. Their composites with carbon (carbon quantum dots, carbon black, carbon nanotubes/nanofibers, graphene/graphene oxides), metals (nickel, platinum, silver), metal oxides (TiO, CoO, CuO, MnO, FeO), metal sulfides/phosphides (CoS, NiCoS, NiP), MOFs (MOF derivatives) and polymers (PEDOT:PSS, PPy (polypyrrole), P(NIPAM-co-SPMA) and PET) are also discussed in this review. The relationship between structures and electrochemical properties as well as the associated charge-storage mechanisms is discussed. Moreover, challenges and prospects of the LDHs for high-performance ECs are presented. This review sheds light on the sustainable development of ECs with LDH based electrode materials.

A summary of the synthesis, modification, and electrochemical performance of Sn-based nanomaterials; lithium/sodium ion batteries and supercapacitors are carefully discussed.

One dimensional (1D) silver-based nanomaterials have a great potential in various fields because of their high specific surface area, high electric conductivity, optoelectronic properties, mechanical flexibility and high electro-catalytic efficiency. In this Review, the preparations of 1D silver-based nanomaterials is classified by structure composed of simple silver nanowires/rods/belts/tubes, core-shells, and hybrids. The latest applications based on 1D silver nanomaterials and their composite materials are summarized systematically including electrochemical capacitors, lithium-ion/lithium-oxygen batteries, electrochemical sensors and electrochemical catalysis. The preparation process, tailored material properties and electrochemical applications are discussed.

The development of inexpensive, highly active, bifunctional electrocatalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is required for many energy conversion systems, including water splitting, fuel cells, and metal-air batteries. This study reports silver nanowires-zeolitic imidazolate framework (Ag NWs-ZIF67) composites as bifunctional electrocatalysts for OER and ORR. The synergistic effects of Co2+, organic ligands, and Ag NWs enhance the bifunctional electrocatalytic properties. Ag NWs improved the electrical conductivity of the Ag NWs-ZIF67 composite toward OER, and porous ZIF-67 on the exterior of this product enabled O2 to fully react with Ag NWs for the ORR because O2 molecules were easily deflected from a planar electrode surface. This study provides valuable insights into the rational design of bifunctional oxygen catalysts having advantages of high performance and low cost.

A Cu–Co3O4 hybrid//activated carbon EES device is successfully assembled, and shows great performance, which represents the first report of this material being applied for supercapacitors.

Dimanganese trioxide microflowers are easily obtained from a Mn(ii) 8-hydroxyquinoline microcoordination after calcination in air. We also look into the possible formation mechanism of the flower-like morphology, and find that the reaction time affects the morphology of the coordination. Furthermore, the as-prepared porous Mn2O3 microflowers are made of many nanoplates which form many nanogaps and nanochannels. Interestingly, the assembled electrode based on the as-prepared porous Mn2O3 microflowers proves to be a high-performance electrode material for supercapacitors. The electrode shows a specific capacitance of 994 F g(-1), which can work well even after 4000 cycles at 0.75 A g(-1). More importantly, the porous Mn2O3 microflowers and activated carbons are assembled into a high-performance flexible solid-state asymmetric supercapacitor with a specific capacitance of 312.5 mF cm(-2). The cycle test shows that the device can offer 95.6% capacity of the initial capacitance at 2.0 mA cm(-2) after 5000 cycles with little decay. The maximum energy density of the device can achieve 6.56 mWh cm(-3) and the maximum power density can also achieve 283.5 mW cm(-3), which are among the best results for manganese based materials.