Mn-基超级电容电极材料的研究进展

Recent Progress in Mn-based Materials as Supercapacitor Electrodes

随着世界经济的快速发展,伴随着化石能源的消耗和严重的环境污染问题出现,积极开发和利用可替代再生清洁能源和能源储存元件显得极为重要.超级电容器,具有功率密度高、充电时间短、使用寿命长、温度特性好、绿色环保等特点被视为最具有潜在实际应用前景的储能装置之一,近年来受到广泛关注.在超级电容器电极材料研究中,由于Mn的氧化态最多,其中大多数Mn-基材料具有特殊的隧道结构,有利于进行氧化还原反应,因此具有非常高的理论电容量,使得Mn-基材料成为极具潜力的储能电极材料.近十年来,人们对Mn-基电极材料进行了深入的研究,并取得突破性的进展.电极的比电容与活性物质的负载质量以及形貌之间存在着及其密切的关系,对Mn-基电极材料的研究集中在物种的结构设计和控制Mn-基物种的形貌来暴露更多的活性位点,在不限制负载质量的情况下,缩小实际电容和理论电容之间的差距.虽然Mn一基材料有诸多优点且最近几年的研究也取得极大的突破,但Mn-基材料本身电导性较差,现有设计的结构还不够优化,结构所暴露的氧化还原活性位点数量不够丰富,其呈现的电化学性能仍远未达到理论容量,亦未能满足实际应用的需要.最近已有关于碳材料复合、形貌及结构改性和合成方法优化等方面对Mn02-基电容器进行综述的报道,但没有不同Mn-基材料电容器相关的综述报道,本文分别从Mn-基材料的储能机理、晶体结构、改性方法以及不同活性物种MnOz、MnO、Mn3O4,Mn(OH)2和其他Mn-基材料的优缺点等方面进行综述,并提出进一步改进材料电化学性能的方向.

Over the past century, energy requirements increased rapidly due to the global development leading to the rapid depletion of conventional fossil fuels as well as the accompanying detrimental environmental issues. Therefore, it is highly urgent to develop renewable, clean alternatives, and usable energy storage devices that can resolve the current problems. Supercapacitors, with high power density, long cycle life, and both economic and environmental advantages, have been widely considered as one promising candidate of green energy storage devices. As one of typical materials showing intrinsic pseudocapacitive behaviors, Mn-based materials are attractive because of owning large potential windows and high theoretical capacitance values, resulting from many accessible oxidation states of Mn and a special tunnel structure. Recent intense studies have made breakthrough in boosting capacitance via conductive component coupling, heterojunction configuring, morphologies controlling, and metal doping to accommodate more redox-active sites. Nevertheless, there is still a wide gap between the practical and theoretical capacitance value due to the naturally poor electrical conductivity of Mn-based materials and imperfectly current structural designs, which greatly hampers in commercial applications. Herein, we systematically review Mn-based materials for supercapacitor electrodes from mechanism, crystalline structures, modification, and comparation of various Mn-based materials, as well as propose possible guides for further improvement.