Highly active, durable, and cost-effective electrocatalysts for water oxidation to evolve oxygen gas hold a key to a range of renewable energy solutions, including water-splitting and rechargeable metal-air batteries. Here, we report the synthesis of ultrathin nickel-iron layered double hydroxide (NiFe-LDH) nanoplates on mildly oxidized multiwalled carbon nanotubes (CNTs). Incorporation of Fe into the nickel hydroxide induced the formation of NiFe-LDH. The crystalline NiFe-LDH phase in nanoplate form is found to be highly active for oxygen evolution reaction in alkaline solutions. For NiFe-LDH grown on a network of CNTs, the resulting NiFe-LDH/CNT complex exhibits higher electrocatalytic activity and stability for oxygen evolution than commercial precious metal Ir catalysts.
Nanometer-sized hydroxide active centers are uniformly and strongly hybridized into a graphene framework by means of defect-anchored nucleation and spatially confined growth, resulting in a superior electrocatalyst for oxygen evolution reaction. This family of strongly coupled complexes and the topology-assisted fabrication strategy is expected to open up new avenues of research. It sheds light on a novel branch of advanced nano-architectured materials.
Nitrogen-doped aligned CNT/graphene sandwiches are rationally designed and in-situ fabricated by a facile catalytic growth on bifunctional natural catalysts that exhibit high-rate performances as scaffolds for lithium-sulfur batteries, with a high initial capacity of 1152 mA h g(-1) at 1.0 C. A remarkable capacity of 770 mA h g(-1) can be achieved at 5.0 C. Such a design strategy for materials opens up new perspectives to novel advanced functional composites, especially interface-modified hierarchical nanocarbons for broad applications.
The solid electrolyte interphases (SEI) formed on Li metal anodes can inhibit the growth of dendrites, improve the Coulombic efficiency, and achieve a superior cycling performance of Li metal batteries. In article number 1500213, Q. Zhang and co‐workers review the formation mechanism, structure model, characterization, and modulation of robust SEI on Li metal.
Self-healing capability helps biological systems to maintain their survivability and extend their lifespan. Similarly, self-healing is also beneficial to next-generation secondary batteries because high-capacity electrode materials, especially the cathodes such as oxygen or sulfur, suffer from shortened cycle lives resulting from irreversible and unstable phase transfer. Herein, by mimicking a biological self-healing process, fibrinolysis, we introduced an extrinsic healing agent, polysulfide, to enable the stable operation of sulfur microparticle (SMiP) cathodes. An optimized capacity (∼3.7 mAh cm) with almost no decay after 2000 cycles at a high sulfur loading of 5.6 mg cm was attained. The inert SMiP is activated by the solubilization effect of polysulfides whereas the unstable phase transfer is mediated by mitigated spatial heterogeneity of polysulfides, which induces uniform nucleation and growth of solid compounds. The comprehensive understanding of the healing process, as well as of the spatial heterogeneity, could further guide the design of novel healing agents (e.g., lithium iodine) toward high-performance rechargeable batteries.
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