超级电容器在器件设计以及材料合成的研究进展

Latest advances in supercapacitors: From new electrode materials to novel device designs

便携电子产品的快速发展以及可再生能源系统的日益扩大,意味着储电系统将在人类社会中扮演着越来越重要的作用.近年来,新一代的超级电容器在材料合成、器件的设计组装以及多功能器件的设计等方面取得了许多重大突破.因此,本文将从新材料的合成、新设备的设计组装以及多功能器件的研发等方面对超级电容器的最新研究进展进行总结.首先,对不同结构的超级电容器及其性能进行详细地讨论,包括三电极(也称半电池)装置、两电极超级电容器、柔性固态超级电容器、纤维超级电容器以及微型(平面)超级电容器等.通过对文献的综合分析,突出介绍了超级电容器的设计原则;其次,对一些新兴电极材料的研发及其储电性能进行了讨论,包括碳材料、双金属氧化物(NiCo_2O_4, Ni_3V_2O_8, Co_3V_2O_8等)、过渡金属硫化物/硒化物/磷化物等正极材料以及VN, Fe_2O_3等负极材料;最后,对下一代的多功能超级电容器,包括自愈合超级电容器、自充电超级电容器、全方位-自适应-自充电超级电容器等器件的研究进展进行总结,概括这一新兴技术领域的未来发展趋势及其关键技术挑战.

Due to the global warming and energy depletion issues, developing sustainable and renewable energy resources has become a critical concern among researchers. The constantly growing demand for energy has urged researchers to develop highly improved energy storage devices. In relation to relevant energy storage systems, supercapacitor technology has drawn burgeoning interest in recent years owing to its environmentally safe and cost effective advantages. Especially, its high power density(>10 kW/kg), fast charge/discharge characteristics, and excellent cycle stability are highly beneficial in storing renewable energy. Currently, the rapid development of portable electronic devices and the expanding renewable energy systems have paved the way for energy storage systems to play an important role in human society. Many significant breakthroughs for the next-generation supercapacitors have been achieved in terms of material synthesis, device innovations, and multifunctional device designs. Therefore, this paper summarizes the latest progress on new materials and novel device assemblies. First, to fully assess the effect of device assembly on supercapacitor performance, five types of supercapacitor structures and their assembly principles are discussed in detail, including the three-electrode(also known as semi-battery) device, two-electrode supercapacitor, flexible solid-state supercapacitor, fiber supercapacitor, and planar(micro-) supercapacitor. Among them, the three-electrode system and the two-electrode device are still the most widely used types at present. The three-electrode cell is suitable for characterizing electrode materials or investigating the electrochemical storage processes. The structure of a two-electrode system is closer to an actual supercapacitor. Other specially designed cells, which are fabricated with the aim of meeting the requirements of flexible and lightweight energy sources, have also been proposed in recent years. The results indicate that the structural innovative design could provide a fascinating way to enhance the energy density of devices while also holding huge potential to enhance the compatibility between supercapacitor component and various portable or wearable electronic devices. A careful interpretation and rigorous scrutiny of the electrochemical characteristics of every supercapacitor is also conducted in this work. Moreover, the design principles for enhancing the supercapacitor performance are highlighted through a comprehensive analysis of the literature. The main challenges in the structural innovations for enhancing the electrochemical performance are analyzed. The solutions to overcome these challenges are proposed. Second, supercapacitors still suffer from a lower energy density compared with Li-ion batteries. Among various efforts to build high-performance supercapacitors in recent years, major improvements have been made in electrode materials with rational designs. This review article also examines the latest methodologies and performance evaluation metrics for several emerging electrode materials in terms of their improved electrochemical properties, including carbon materials, binary transition metal oxides(NiCo2O4, Ni3V2O8, and Co3V2O8, among others), transition metal chalcogenides/selenide/phosphide positive electrodes, and VN, Fe2O3 negative electrode materials. This paper also highlights the electrode material design principle, which is the fundamental understanding of the relationships between structural design, structural properties and components of electrode materials and their electrochemical performances. Moreover, we also summarized the latest contributions and progress in multifunctional supercapacitors, which include the transparent flexible supercapacitor, self-healable supercapacitor, piezoelectric supercapacitors, self-charging supercapacitors, and so on. Several methods to realize the abilities of transparent, folded, wearable, self-healable, and even self-chargeable supercapacitors with almost no performance degradation are discussed. This paper also analyzes the compatibility of a multifunctional supercapacitor with industrial manufacturing, and offers a paradigm for developing portable and wearable energy storage devices and systems. Furthermore, the operating principles, system design/engineering, and the rational optimization of the multifunctional supercapacitors are also analyzed in this review. Finally, the major challenges faced by next-generation supercapacitors, along with the future research prospects, are discussed at the end of the paper.