Yang Yuanhaobo, Chen Biao, Zhang Yongbo, Peng Hongchao, Chen Jia, Chen Sheng
College of Biomass Science and Engineering, National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065, China.
Down-Hole Service Company of Sinopec Shengli Petroleum Engineering Co., Ltd., Dongying 257066, China.
ACS Appl Mater Interfaces. 2024 Aug 14;16(32):42502-42512. doi: 10.1021/acsami.4c09004. Epub 2024 Aug 3.
Vanadium pentoxide (VO) is considered a promising material for electrochromic supercapacitors due to its rich color transitions and excellent electrochemical capacity. However, VO exhibits low electrical conductivity, and its volume changes dramatically during charge-discharge cycles, leading to structural collapse and poor long-term cyclability. These issues have hindered the development and application of VO. In this study, copper vanadium oxide yolk-shell microspheres (CVO) were synthesized through a one-step solvent heat treatment with an annealing process. With the doping of copper element, the capacitance, conductivity, and cyclic stability of CVO microspheres were significantly enhanced. Subsequently, the sphere-wire network structure was formed by blending NaVO·3HO nanowires (NVO), resulting in the formation of CVO/NVO composites. The three-dimensional sphere-wire network efficiently facilitates the acquisition of additional redox sites and strengthens the material-to-substrate bonding. Under the combined influence of these favorable factors, CVO/NVO achieved a high specific capacitance of 39.2 mF cm, with a capacitance retention of 84% after 7500 cycles at a current density of 0.7 mA cm. The fully inorganic solid-state electrochromic supercapacitor (ECSC), assembled on the basis of CVO/NVO, demonstrates a vivid and clearly distinguishable color change (Δ* = 37). Even more impressive is the energy storage capacity (18.4 mF·cm) and the cycling stability (up to 89% retention after 10,000 cycles) exhibited by the devices. These key performances are superior to those of most of the previously reported VO-based ECSCs, opening a promising avenue for the development of VO-based electrochromic energy storage devices.
五氧化二钒（VO）因其丰富的颜色转变和出色的电化学容量，被认为是用于电致变色超级电容器的一种很有前景的材料。然而，VO的电导率较低，并且在充放电循环过程中其体积会发生显著变化，导致结构坍塌和较差的长期循环稳定性。这些问题阻碍了VO的开发和应用。在本研究中，通过一步溶剂热处理并结合退火工艺合成了铜钒氧化物蛋黄壳微球（CVO）。随着铜元素的掺杂，CVO微球的电容、电导率和循环稳定性得到显著提高。随后，通过混合NaVO·3HO纳米线（NVO）形成了球-线网络结构，从而形成了CVO/NVO复合材料。三维球-线网络有效地促进了额外氧化还原位点的获取，并加强了材料与基底的结合。在这些有利因素的共同影响下，CVO/NVO实现了39.2 mF cm的高比电容，在0.7 mA cm的电流密度下经过7500次循环后电容保持率为84%。基于CVO/NVO组装的全无机固态电致变色超级电容器（ECSC）表现出鲜明且清晰可辨的颜色变化（Δ* = 37）。更令人印象深刻的是这些器件所展现的储能容量（18.4 mF·cm）和循环稳定性（在10,000次循环后高达89%的保持率）。这些关键性能优于大多数先前报道的基于VO的ECSC，为基于VO的电致变色储能器件的开发开辟了一条有前景的途径。
