K3Fe(CN)6增强钴镍基硒化物的电化学性能研究

Enhanced Supercapacitive Performance of Nickel Cobalt Selenide with K3Fe（CN）6 Additive in Aqueous Electrolyte

摘要:

作为一种新型的电化学储能器件，超级电容器具有高功率密度，长循环寿命等优点。然而，超级电容器普遍具有能量密度低的缺陷，限制了其在高能量密度领域的应用。寻找具有高比电容的赝电容电极材料是目前研究重点。此外，在常规电解液中添加氧化还原添加剂，亦被认为是一种有效提升超级电容器电化学性能的手段。采用共沉淀法制备了作为超级电容器电极材料的多孔钴镍基过渡金属硒化物（NCSe）立方体，同时在碱性电解液中添加了具有氧化还原活性的K₃Fe(CN)₆的添加剂。研究结果表明，在电解液中加入K₃Fe(CN)₆，可使超级电容器的电化学特性得到提升。在2 A?g^-1电流密度下，在1 mol?L^-1的KOH电解液中，NCSe比电容仅仅为48.1 F?g^-1；而当电解液中添加0.02 mol?L^-1的K₃Fe(CN)₆后，在同样的电流密度下，NCSe比电容高达1 070.1 F?g^-1。因此，在碱性电解液中加入一定量的具有氧化还原作用的K₃Fe(CN)₆添加剂，可以有效提升超级电容器的电化学性能。

Abstract:

Supercapacitors are regarded as promising energy storage devices with the advantages of high-power density and long cycling life. However， restricted by the intrinsic electrical double layer mechanism of carbon electrodes， the supercapacitors exhibit relatively low energy density， which inhibits their practical applications. Seeking for electrode materials with high theoretical specific capacitance and introducing redox additives into electrolyte are recognized as two effective strategies to improve the electrochemical performances of supercapacitors. Herein， we prepared porous nickel cobalt selenide nanocubes via a simple coprecipitation method for supercapacitors. By adding 0.02 mol?L^-1 K₃Fe（CN）₆ into 1 mol?L^-1 KOH electrolyte， the supercapacitive performance could be significantly improved. A high specific capacitance of 1 070.1 F?g^-1 can be achieved at the current density of 2 A?g^-1 in KOH（1 mol?L^-1）+K₃Fe（CN）₆（0.02 mol?L^-1）， which is much higher than that in pure 1 mol?L^-1 KOH. The results demonstrated that introducing redox species into conventional aqueous electrolyte could effectively improve the electrochemical performance of supercapacitors.