Anions Regulation of 1D Perovskite Intrusion-Behavior for Efficient and Stable Perovskite Solar Cells.

Constructing a 1D/3D perovskite heterojunction has recently emerged as a prevalent approach for elevating the efficiency and stability of perovskite solar cells (PSCs), due to the excellent defect-passivation capacity and enhanced resistance to water and oxygen of 1D perovskite. However, the 1D perovskite commonly exhibits much poorer charge carrier transport ability when compared with its 3D counterpart. Tailoring the intrusion depth of a 1D perovskite into the 1D/3D heterojunction is thus of key importance for PSCs but remains a great challenge.

Phase Engineering and Dispersion Stabilization of Cobalt toward Enhanced Hydrogen Evolution.

Phase engineering is promising to increase the intrinsic activity of the catalyst toward hydrogen evolution reaction (HER). However, the polymorphism interface is unstable due to the presence of metastable phases. Herein, phase engineering and dispersion stabilization are applied simultaneously to boost the HER activity of cobalt without sacrificing the stability.

Direct Surface Passivation of Perovskite Film by 4-Fluorophenethylammonium Iodide toward Stable and Efficient Perovskite Solar Cells.

Passivating the defective surface of perovskite films is becoming a particularly effective approach to further boost the efficiency and stability of their solar cells. Organic ammonium halide salts are extensively utilized as passivation agents in the form of their corresponding 2D perovskites to construct the 2D/3D perovskite bilayer architecture for superior device performance; however, this bilayer device partly suffers from the postannealing-induced destructiveness to the 3D perovskite bulk and charge transport barrier induced by the quantum confinement existing in the 2D perovskite. Hence, developing direct passivation of the perovskite layer by organic ammonium halides for high-performance devices can well address the above-mentioned issues, which has rarely been explored.

Li metal deposition and stripping in a solid-state battery via Coble creep.

Solid-state lithium metal batteries require accommodation of electrochemically generated mechanical stress inside the lithium: this stress can be up to 1 gigapascal for an overpotential of 135 millivolts. Maintaining the mechanical and electrochemical stability of the solid structure despite physical contact with moving corrosive lithium metal is a demanding requirement. Using in situ transmission electron microscopy, we investigated the deposition and stripping of metallic lithium or sodium held within a large number of parallel hollow tubules made of a mixed ionic-electronic conductor (MIEC).

Valence Engineering via Selective Atomic Substitution on Tetrahedral Sites in Spinel Oxide for Highly Enhanced Oxygen Evolution Catalysis.

A major challenge that prohibits the practical application of single/double-transition metal (3d-M) oxides as oxygen evolution reaction (OER) catalysts is the high overpotentials during the electrochemical process. Herein, our theoretical calculation shows that Fe will be more energetically favorable in the tetrahedral site than Ni and Co, which can further regulate their electronic structure of binary NiCo spinel oxides for optimal adsorption energies of OER intermediates and improved electronic conductivity and hence boost their OER performance. X-ray absorption spectroscopy study on the as-synthesized NiCoFe oxide catalysts indicates that Fe preferentially dopes into tetrahedral sites of the lattice, which induces high proportions of Ni and Co on the octahedral sites (the active sites in OER).

Facile synthesis of a mechanically robust and highly porous NiO film with excellent electrocatalytic activity towards methanol oxidation.

Considerable research is being conducted in searching for effective anode catalysts in alkaline direct methanol fuel cells (DMFCs). Although significant progress has been achieved, it is still challenging to prepare non-Pt catalysts with both excellent activity and good durability. Herein, a highly porous NiO film is developed by a facile and fast anodization approach.

Sponge-like Ni(OH)2-NiF2 composite film with excellent electrochemical performance.

Sponge-like porous Ni(OH)(2)-NiF(2) composite (PNC) film was successfully synthesized by the anodization of nickel in a NH(4)F and H(3)PO(4) containing electrolyte. Thanks to the good conductivity and the highly porous architecture, PNC exhibited not only a high specific capacitance, but also a superior rate capability and a good cyclability (2090 F g(-1) at 10 mV s(-1), capacitance >1200 F g(-1) at 100 A g(-1) after 2000 cycles). Anodization of nickel is proven to be fast and facile and can be easily scaled up.

A facile route to fabricate an anodic TiO2 nanotube-nanoparticle hybrid structure for high efficiency dye-sensitized solar cells.

The relatively low internal surface area of anodized TiO(2) nanotube arrays (TNAs) limits dye adsorption and light capturing in TNA-based dye-sensitized solar cells (DSSCs). Here, water treatment of as-anodized TNAs at room temperature was used to tailor the geometry of TNA walls in a controllable way, leading to a hybrid tube wall structure with the outer shell in a tubular morphology and the inner surface consisting of small particles. To enable front-side illumination in DSSCs, the TNAs with porous inner walls were transferred to transparent conductive oxide substrates by a self-detaching and transfer technique.

Enhanced charge storage by the electrocatalytic effect of anodic TiO₂ nanotubes.

Ordered titania nanotube (TNT) arrays were fabricated by anodization of titanium with a very fast voltage ramp speed. Co(OH)(2)/TNT nanocomposite was synthesized by cathodic deposition using the as-anodized TNT as the substrate. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) were used to characterize the morphology, crystalline structure and chemical state.

Polyaniline nanowire array encapsulated in titania nanotubes as a superior electrode for supercapacitors.

Conducting polymer with 1D nanostructure exhibits excellent electrochemical performances but a poor cyclability that limits its use in supercapacitors. In this work, a novel composite electrode made of polyaniline nanowire-titania nanotube array was synthesized via a simple and inexpensive electrochemical route by electropolymerizing aniline onto an anodized titania nanotube array. The specific capacitance was as high as 732 F g(-1) at 1 A g(-1), which remained at 543 F g(-1) when the current density was increased by 20 times.