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Uniform C-Al2O3 composite coating with homogeneous thickness was adopted to improve the electrochemical properties of LiNi0.6Co0.2Mn0.2O2 by the pyrolysis of molecular layer deposited alucone in argon. Compared with LiNi0.6Co0.2Mn0.2O2 coated atomic layer deposited Al2O3, C-Al2O3 coated electrode delivered high discharge capacity, good rate capability and durable cyclic stability, even at elevated temperature. Such enhanced electrochemical performance could be attributed to the synergistic effect between the amorphous Al2O3 and conductive carbon in the dual-functional C-Al2O3 composite coating, resulting in the improved structural stability and electrochemical kinetics of LiNi0.6Co0.2Mn0.2O2 cathode. The network of carbon in C-Al2O3 composite coating supplied high electrical conductivity, and lowers the charge transfer resistance on the surface of electrode. Meanwhile, the uniform amorphous Al2O3 with its flexible structure improved the structural stability of cathode and favored the diffusion of Li+ ions.

We pioneered to employ room temperature atomic layer deposition (RTALD) to fabricate flexible Al-Ti-O based metal-insulator-metal (MIM) capacitors on three polymer substrates of polyethylene terephthalate (PET), polyimide (PI) and epoxy resin (epoxy) without any post-processing. Zn was introduced to Al-Ti-O dielectrics to tune its electrical properties through varying ALD cycle ratio and cycle number. Under the optimal processing, the flexible MIM capacitors of Al1.56Ti0.47Zn0.06O3 exhibits comprehensively better performance such as higher capacitance density of 7.4 fF/μm2, smaller leakage current density of 2 × 10−8 A/cm2 at 3 V, and reasonable quadratic voltage linearity of 422 ppm/V2. X-ray photoelectron spectroscopy analyses reveal that the incorporation of a slight amount of Zn into Al-Ti-O dielectrics significantly decreases the oxygen vacancy concentration from 6.7% to 0.8%, beneficial for the improvement of electrical performance. Furthermore, our 2 × 2 cm2 flexible MIM capacitors could bear 4000 bending cycles at bending radius of 8.2 mm, showing better electrical stability. These results indicate that RTALD-derived Al-Ti-Zn-O dielectrics are competitive MIM capacitor candidates for flexible electronics and wearable devices. RTALD technology exhibits exciting potentials in flexible electronic device fabrication.

Ultrathin ZnO coatings with different thicknesses are successfully deposited onto the layered Li-rich oxide Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 via atomic layer deposition (ALD) technology, followed by annealing in Ar. The influence of ZnO layer on the structural and electrochemical performances of Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 cathode material is systematically investigated. In comparison with the pristine one, the ultrathin ZnO-coated electrodes exhibit the significantly improved discharge capacity and cycleability, particularly the LMNCO@ALD-ZnO-20 sample. The remarkably improved electrochemical performance of the coated sample is ascribed to the homogeneous ZnO coatings with high-quality, which could improve the electrode/electrolyte interface stability and the structural stability at high voltage, suppress the increasing charge transfer resistance during cycling, and favour the Li + diffusion.

A simple method to prepare TiO2/g-C3N4 nanocomposite photocatalysts by atomic layer deposition (ALD) has been developed. A uniform ultra-thin TiO2 coating was coated conformally on g-C3N4 powders via ALD. After 500 °C annealing process, amorphous TiO2 turns into anatase nanocrystals and forms heterojunctions between TiO2 and g-C3N4, which greatly improves the separation efficiency of photo-generated carriers of g-C3N4. Moreover, an exfoliation phenomenon of g-C3N4 based on ALD is also observed with dramatically increased specific surface areas from 10.4 m2/g (g-C3N4) to 31.2 m2/g (annealed TiO2/g-C3N4), providing a new way for the exfoliation of layered materials. As a result, annealed 50TiO2/g-C3N4 nanocomposite exhibits the best photocatalytic activity with the methyl orange degradation efficiency of 98.2% in 90 min under visible light irradiation, much better than pure g-C3N4 with only 45% degradation efficiency. The first-order reaction rate constant of annealed TiO2/g-C3N4 nanocomposite is 0.0406 min−1 with the half-life period of only 17 min, which is 5.8 times higher than that of the pure g-C3N4 powders. The enhanced photocatalytic performance of annealed TiO2/g-C3N4 nanocomposites can be ascribed to the synergetic effect of heterojunctions between crystalline TiO2 and g-C3N4 and the increased specific surface areas. Above all, ALD may be a kind of promising and feasible method to fabricate g–C3N4–based nanocomposite powders for photocatalytic applications.

Ultrathin ZrO2 coatings are successfully adopted to modify the surface of the layered LiNi0.5Co0.2Mn0.3O2 cathode material via atomic layer deposition (ALD) technology. Compared with the bare LiNi0.5Co0.2Mn0.3O2, the ultrathin ZrO2-coated cathode materials exhibited a significantly improved discharge capacity and cycleability. Among all of the samples, ZrO2-coated LiNi0.5Co0.2Mn0.3O2 electrode with 5 ALD layers showed highest initial Coulombic efficiency, excellently electrochemical cycleability and high rate capability in the voltage range of 2.5–4.5 V at room temperature. Furthermore, this sample showed a discharge capacity of 155.1 mAh g−1 with a high retention of 88.1% at the current of 1000 mA g−1 (5C) after 60 cycles at the elevated temperature of 55 °C, which demonstrated a remarkable enhancement about 150% over that of the bare one. Such enhanced electrochemical performance can be attributed to the high-quality ultrathin ALD metal oxide coating for the cathode material, which protects the cathode material from the undesirable side reaction with the electrode and suppresses the increasing impedance in order to facilitate the diffusion of lithium ion into the host oxide.

A simple approach is developed to fabricate oxide/FePt nanocrystals/oxide composite films by a combination of chemically-synthesized FePt nanocrystals’ self-assembly and atomic layer deposition for ultrahigh-density nonvolatile memory applications. A hexagonally arranged monolayer of well-monodispersed FePt nanocrystals with a grain size of 4.5 nm has been assembled onto atomic-layer-deposited Al 2 O 3 oxide by solution-based dip-coating. The lattice constant of this two-dimensional pattern is about 8 nm with the high density of 1.8 × 10 12 /cm 2 . A fraction of the Fe is oxidized during annealing at 500 °C for 5 min in O 2 atmosphere, and the core–shell structure is formed with fcc-Fe 0.75 Pt nanocrystal core and amorphous Fe 2 O 3 shell. The metal–oxide–Si capacitors with unannealed and annealed FePt nanocrystals embedded into Al 2 O 3 films are electrically measured, and exhibit obvious memory effects with a hysteresis memory window of 4.1 and 8.1 V at the sweeping gate voltage of ±8 V, respectively. The enhanced memory window of samples with annealed FePt nanocrystals can be attributed to the existence of the Fe 2 O 3 shell, which introduces additional interface and provides more trap sites for charge trapping storage.

FePt nanoparticles (NPs) have been encapsulated in the insulating and protective oxide matrix, using a sol–gel process, in order to prevent particles from agglomerating and sintering during the heat-treatment process required for the L 1 0 ordering. The microstructural and ferromagnetic properties of FePt/TiO 2 nanocomposites were characterized. The presence of oxide-matrix leads to more homogeneous microstructures and better magnetic properties. The short range positional order of the FePt NPs can be preserved upon annealing at 700 °C to possess higher room-temperature coercivities ( H C = 3.7 kOe). Such nanocomposites with assemblies of high-coercivity magnetic nanoparticles are attractive for realizing new types of ultra-high-density data storage devices and magneto-composites.

Triclinic beta-BiNbO4 prepared below 750 degrees C and above 1040 degrees C (denoted as Low-beta and High-beta, respectively) and pure orthorhombic alpha-BiNbO4 at 900 degrees C were successfully derived from a citrate method and the phase transition from beta-BiNbO4 to alpha-BiNbO4 was first observed in BiNbO4 powders. This phenomenon proves that the abnormal phase transition from beta-BiNbO4 to alpha-BiNbO4 exists in BiNbO4 powder system. The synthesis of Low-beta powders can be attributed to the formation of the intermediate phase of Bi5Nb3O15 by the citrate method. With increasing temperature, the Low-beta phase gradually turns into alpha-BiNbO4 due to the thermodynamically metastable state of Low-beta. We also identified that the stress in pellet format can accelerate the phase transition from Low-beta to alpha phase of BiNbO4 in comparison with powder samples. It brings us new understanding of the BiNbO4 system and also provides a simple way to obtain BiNbO4 for microwave and photocatalytic applications.

SrZrO 3 thin films are prepared on Pt/TiO 2 /SiO 2 /Si substrates by sol–gel process for resistive random access memory applications. The unipolar resistive switching characteristic is achieved in both stoichiometric and Zr-deficient SrZrO 3 thin films. Formation and rupture of filaments composed of oxygen vacancies are proposed to explain the observed resistive switching behaviors. By introducing oxygen vacancies into SrZrO 3 through making the film Zr-deficient, the conduction mechanism of the high resistance state changes from Ohmic to space charge limited behavior. This may be ascribed to more deep traps associated with oxygen vacancies due to Zr-deficiency. Switching endurance is enhanced significantly in Zr-deficient SrZrO 3 due to the reduced Joule heating.