基于原子层沉积技术的先进能源材料设计

Design of advanced energy-related materials via atomic layer deposition

随着能源危机和环境污染等问题的不断加剧,设计并制备新一代能源材料实现能源的优化利用、转化和储存是当今能源研究领域关注的重点.原子层沉积技术(atomic layer deposition,ALD)是一种新兴的纳米材料制备和表面改性技术,具有沉积材料结构均一、区域选择性强、原子级精准可控等优势,可以实现金属单质、金属氧化物、金属硫化物、金属氮化物等多种类材料的可控制备,因而在众多领域得到了研究应用.本文首先简要阐述了ALD的技术原理和特点,之后重点介绍了其在能源小分子催化转化利用和清洁能源转化储存两大领域的应用,总结了其在能源材料理性设计和精准制备方面的优势.最后,针对目前ALD存在的难点和挑战,展望了其在能源材料领域的应用前景和未来的研究趋势.

Fossil fuels,such as coal,oil,and natural gas,have supported the development of human society for a long time as representative energy carriers and resources for chemical production.However,their huge demand and overutilization have led to the unavoidable depletion of fossil fuels and caused serious environmental issues,thus increasing urgent crises for the future of human beings.Considering the energy and environmental issues,breakthroughs in materials technology remain key to improving the efficiency of chemical production from fossil resources and exploiting alternative energy sources,which are highly desirable for the sustainable development of human society.Nanomaterials have been extensively studied and widely implemented in energy-related applications,such as catalysts,cells,and supercapacitors,due to their huge specific surface areas,favorable transport properties,and unique physical and chemical properties,such as confinement effects resulting from their nanoscale dimensions.Among these applications,catalysts can substantially reduce the consumption of fossil resources by catalyzing the fossil-related chemical process with high activity and selectivity and converting alternative resources(e.g.,H2O and CO_(2))into clean energy carriers and highvalued chemicals;moreover,cells and supercapacitors serve crucial roles in conversion and storage of electric energy from sunlight or water,providing great potential for development of alternative energies.Therefore,the design and synthesis of well-defined nanomaterials with superior performance in catalysis,conversion,or storage is the key to relieving or even solving urgent issues on energy and the environment.Thus far,energy-related nanomaterials have been synthesized with exceptional functionality as synthetic technology improves by leaps and bounds.However,the complex structures and compositions of many products hinder the optimization of the functionality and comprehension of the underlying structure–function relations.It is highly desirable to develop a simple method to precisely tune the surface–interface structure,composition,hierarchy,and local environment at the atomic level,facilitating the rational design of energyrelated nanomaterials with unprecedented functionality.Atomic layer deposition(ALD),a type of gas-phase thin film deposition process with self-limiting and saturated surface reactions,is a powerful tool for surface and interface engineering to explore energy-related materials due to its exceptional capability of precise thickness control,excellent uniformity and conformity,and convenient composition regulation.In the past few decades,ALD has been intensively studied for energy-related catalysis,conversion,and storage applications with remarkable progress.In this review,the design and synthesis of catalysts,cells,and supercapacitors for energy-related applications by ALD are focused on.First,the mechanism of ALD and its distinct advantages over other deposition methods are discussed in brief.Subsequently,the state-of-the-art achievements of catalysts,cells,and supercapacitors prepared by ALD are examined in detail.Regarding energy-related catalytic materials,advances in well-defined catalysts with extraordinary catalytic performance for conversion and/or efficient upgrading of energy-related molecules,such as CO,CO_(2),H2,and gaseous hydrocarbons,are reviewed.It is highlighted and elucidated that substantial ALD synthesis strategies could result in remarkable catalytic performance by fabricating catalytic active centers with tunable structure,composition,and local environment.Regarding energy conversion and storage materials,recent progress on the design of delicate solar cells,Liion cells,fuel cells,and supercapacitors by ALD is summarized.It is emphasized that ALD is extensively employed to improve the device performance by synthesizing,modifying,or stabilizing their components,including anode,cathode,electrolyte,and protective layer.Lastly,the challenges of precursor preparation in ALD and expanding the scale of manufacturing are also discussed.