Wang Yangyang, Xu Lin, Wang Zongyu, Pu Zepeng, Yuan Yapeng, Li Xiaodong, Liu Xuehua, Fu Aiping, Li Yanhui, Li Hongliang
Institute of Materials for Energy and Environment, College of Materials Science and Engineering, Qingdao University, Qingdao 266071, China.
College of Chemistry and Chemical Engineering, Qingdao University, Qingdao 266071, China; State Key Laboratory of Bio-Fibers and Eco-Textile, Qingdao University, Qingdao 266071, China.
J Colloid Interface Sci. 2022 Sep 15;622:748-758. doi: 10.1016/j.jcis.2022.04.143. Epub 2022 Apr 29.
The vanadium dioxide (VO(D)), with ultra-high theoretical capacitance, has been considered as a boon for electrode materials of advanced supercapacitors (SCs). However, the VO has a series of shortcomings such as poor electrical conductivity, severe structural damage, and rapid capacity fading during cycles, resulting in unsatisfactory electrochemical performance. Herein, the Co pre-intercalation and amorphous carbon confined vanadium dioxide (CoxVO@C) with starfruit-like nanostructure is synthesized on a conductive Ni foam substrate via a versatile and cost-effective method. As a cathode for SCs, the obtained CoxVO@C not only enables a small amount of Co pre-intercalation layer to offer faster ion diffusion kinetics for VO, but also utilizes a high-conductivity amorphous carbon to protect VO from dissolution in an alkaline electrolyte, thereby exhibiting the ultrahigh specific capacitance up to 4440.0 mF cm at 5 mA cm (525.2 F g at 2 A g) and the prominent long-term stability performance of the electrode. Benefited from these excellent characteristics, a high-performance CoxVO@C//VO hybrid supercapacitor (HSC) device with an operating voltage of 1.7 V is further assembled. The HSC device delivers a superior energy density of 102.3 W h kg at a power density of 6.1 kW kg, manifesting its practical feasibility.
二氧化钒（VO₂）具有超高的理论电容，被认为是先进超级电容器（SCs）电极材料的福音。然而，VO₂存在一系列缺点，如电导率差、结构严重受损以及循环过程中容量快速衰减，导致电化学性能不尽人意。在此，通过一种通用且经济高效的方法，在导电泡沫镍基底上合成了具有杨桃状纳米结构的钴预插层和非晶碳限制的二氧化钒（CoxVO@C）。作为SCs的阴极，所获得的CoxVO@C不仅使少量的钴预插层为VO₂提供更快的离子扩散动力学，还利用高导电性的非晶碳保护VO₂在碱性电解质中不溶解，从而在5 mA cm⁻²时表现出高达4440.0 mF cm⁻²（在2 A g⁻¹时为525.2 F g⁻¹）的超高比电容以及电极出色的长期稳定性性能。受益于这些优异特性，进一步组装了工作电压为1.7 V的高性能CoxVO@C//VO₂混合超级电容器（HSC）器件。该HSC器件在功率密度为6.1 kW kg⁻¹时提供了102.3 W h kg⁻¹的优异能量密度，表明了其实际可行性。
