Atomic layer deposition (ALD) relies on self-limiting reaction within a cyclic process and is being considered as a potential technique for synthesizing nanomaterials with precisely controlled internal structure. Therefore, the design and synthesis of advanced ultrafine nanomaterials becomes feasible through a rigorous control over the morphology, micro-and nano-structure, composition, thickness and particle size. Currently, ALD is mostly adopted for semiconductor applications; however, several other areas (i.e. catalysis and energy storage) can hugely benefit from ALD capabilities if the process is finely tuned. In this review paper, significant previous works on ALD of nanomaterials have been discussed via focusing on the deposition of noble metals, metal oxides, two-dimensional materials and metal-organic frameworks on various substrates. Major contributing parameters (e.g. deposition temperature, ALD cycles, and type of the precursor) affecting the deposition process have also been covered. The review concludes with a summary of opportunities for future research to enable large-scale implementation of ALD as a reliable and robust technique for synthesizing nanomaterials.
Conformal coating of ceramic layers (nm-thick) on Ni-rich layered cathode materials is an effective strategy for improving high-temperature longevity of Li-ion batteries (LIBs). In this work, we develop a roll-to-roll atomic layer deposition (R2R ALD) apparatus for growing uniform nanolayers of TiO 2 . We explore the effect of ALD parameters (temperature: 120−180 °C and line speed: 2−40 mm s −1 ) on the TiO 2 surface coating and subsequently investigate the electrochemical performance of the as-prepared cathodes. The capacity retention of TiO 2 -coated porous electrodes is substantially improved compared to that of the pristine cathode material for high-temperature cycling. Electrochemical impedance spectroscopy confirms that the ALD-TiO 2 coating suppresses the undesired side reactions initiated at the electrode/electrolyte interface, reduces charge transfer resistance, and ultimately facilitates the Li + transport through the composite cathode nanostructure. The robust design of the ALD-TiO 2 cathode material enables high-temperature operation (>55 °C) with enhanced specific capacity, superior rate capability, excellent cyclability, and ultra-high coulombic efficiency within a wide potential window (3.0−4.35 V). The R2R ALD technique developed in this work paves the way for large-scale fabrication of ceramic-coated cathode sheets with a production rate reaching 2.4 m min −1 for a continuous coating operation.
Lithium ion batteries (LIBs) are encouraging electrochemical devices with remarkable properties including high energy/power density, fast charging capability, and low self-discharge rate. Further increase in energy density as well as...
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