possess lower hardness, higher strength, higher elasticity, higher tensile strength, lower internal energy, higher interatomic forces, lower viscosity coefficient, larger surface area, higher chemical stability, and strong corrosion resistance compared with their crystalline counterparts. [1][2][3] Based on the anionic constituents, amorphous materials could be categorized as oxides, sulfides, phosphates, etc. Among them, amorphous metal oxide family is of great importance owing to its widespread applications in a variety of areas such as batteries, supercapacitors, electronics, conducting films, multilayered transistors, electrochromic displays, nonvolatile memories, and the like. [4][5][6] As the basic building blocks, metaloxide (M-O) polyhedra are responsible for the essential features of the electronic band structure in amorphous metal oxides (AMOs). [3] AMO materials differ from their crystalline counterparts in the arrangement of M-O polyhedra, in which a random network arrangement of distorted polyhedra with short-range ordering is presented rather than maintaining perfect periodicity. [7,8] The coordination number of the M-O polyhedra, namely, the number of anions bonded to the metal cation, constitutes a crucially decisive factor for the unique properties of AMOs. Multiple polyhedra are interconnected through different types of sharing configurations known as edge sharing, corner sharing, and face sharing of the oxygen atoms. The combination of different sharing geometries also affects the properties of AMOs. [9] In other words, AMOs are formed by the superposition of the distorted M-O polyhedra to form network arrays through a random package. Long-range structural disorder in the AMO reduces scattering mean free path, and the lack of grain boundaries makes the electronic properties identical within large areas. These unique characteristics make them suitable for flexible electronics such as flexible films, intervening layers, thin film transistors, etc. [10][11][12] In recent years, there are numerous reports pointing out the advantages of AMOs over the crystalline counterparts in many electrochemical applications. [13][14][15][16][17] For example, the inherent disorderliness in the structural arrangement and rich defects are evidenced to be highly constructive to improve the alkali ion diffusion through the lattice. [18,19] As for intercalation-type electrodes in lithium-ion batteries (LIBs), amorphous materials Amorphous metal oxides (AMOs) have aroused great enthusiasm across multiple energy areas over recent years due to their unique properties, such as the intrinsic isotropy, versatility in compositions, absence of grain boundaries, defect distribution, flexible nature, etc. Here, the materials engineering of AMOs is systematically reviewed in different electrochemical applications and recent advances in understanding and developing AMO-based high-performance electrodes are highlighted. Attention is focused on the important roles that AMOs play in various energy storage and conversion technologies...

Atomic layer deposition (ALD) of the iron-group transition-metal diselenides FeSe2, CoSe2, and NiSe2 is reported for the first time. The ALD processes employ the associated metal amidinates as the metal precursors and diethyldiselenide (DEDSe) as the selenium precursor, together with Ar/H2 plasma for DEDSe activation. All of the ALD processes are able to grow highly pure, smooth, and crystalline MSe2 (M = Fe, Co, Ni) films with ideal layer-by-layer film growth behavior, which highlights good controllability over film quality and fabrication process as benefited from ALD. It is further demonstrated that all of the MSe2 films can be uniformly deposited into 10:1 high-aspect-ratio microtrenches with excellent conformality, which underscores the great promise of these processes for conformal MSe2 coatings on three-dimensional (3D) complex topologies in general. In situ ALD mechanism investigation further reveals that the efficient dissociation of DEDSe by plasma is key to the success of these ALD processes.

Rechargeable Zn−air batteries are a promising type of metal-air batteries for high-density energy storage. However, their practical use is limited by the use of costly noble-metal electrocatalysts for the sluggish kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) occurred at the air electrode of the Zn−air batteries. This work reports a new non-precious bifunctional OER/ORR electrocatalyst of NiS x /carbon nanotubes (CNTs), which is made by atomic layer deposition (ALD) of nickel sulfide (NiS x ) on CNTs, for the applications for the air electrode of the Zn−air batteries. The NiS x /CNT electrocatalyst on a carbon cloth electrode exhibits a low OER overpotential of 288 mV to reach 10 mA cm−2 in current density, and the electrocatalyst on a rotating disk electrode exhibits a half-wave ORR potential of 0.81 V in alkaline electrolyte. With the use of the NiS x /CNT electrocatalyst for the air electrode, the fabricated aqueous rechargeable Zn−air batteries show a fairly good maximum output power density of 110 mW cm−2, which highlights the great promise of the ALD NiS x /CNT electrocatalyst for Zn−air batteries.

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