{"title":"Reduced TiO2 nanotube array electrode based supercapacitor with kilohertz frequency response","authors":"Jayant Nagar, Anupam Shukla","doi":"10.1016/j.jpowsour.2024.234951","DOIUrl":null,"url":null,"abstract":"<div><p>Enhancing the frequency of traditional supercapacitors to hundreds or thousands of Hz enables them to replace bulky aluminum electrolytic capacitors for line filtering and function as storage device for the harnessed ambient noise energy for powering the distributed sensor networks and IoT. This work reports a kHz frequency-capable pseudocapacitor comprising electrodes with anatase nanotube arrays (NTA). NTA are grown in-situ via anodization of a titanium foil, providing excellent electrical contact with the underlying unconverted titanium foil. The use of an organic electrolyte (glycerol and ethylene glycol solvent) allows greater control over NTA growth and enables fine-tuning of morphology. Electrochemical reduction of the NTA significantly lowers electrode resistance, thereby enhancing oxygen vacancies and leading to a two-order-of-magnitude rise in charge carrier density (from 2.20 × 10<sup>19</sup> cm<sup>−3</sup> to 1.03 × 10<sup>21</sup> cm<sup>−3</sup>), as determined by Mott-Schottky analysis. The electrode exhibits a high areal capacitance of 1517 <span><math><mi>μ</mi></math></span>F cm<sup>−2</sup> and a phase angle of <span><math><mrow><mo>−</mo><mn>81</mn><mo>.</mo><mn>5</mn><mo>°</mo></mrow></math></span> at 120 Hz. This performance compares favorably with most carbon-based kHz supercapacitor electrodes. The upper-frequency limit of operation for the pseudocapacitor, as measured by the self-resonance frequency, is a high value of 80 kHz.</p></div>","PeriodicalId":377,"journal":{"name":"Journal of Power Sources","volume":null,"pages":null},"PeriodicalIF":8.1000,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Power Sources","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0378775324009030","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Enhancing the frequency of traditional supercapacitors to hundreds or thousands of Hz enables them to replace bulky aluminum electrolytic capacitors for line filtering and function as storage device for the harnessed ambient noise energy for powering the distributed sensor networks and IoT. This work reports a kHz frequency-capable pseudocapacitor comprising electrodes with anatase nanotube arrays (NTA). NTA are grown in-situ via anodization of a titanium foil, providing excellent electrical contact with the underlying unconverted titanium foil. The use of an organic electrolyte (glycerol and ethylene glycol solvent) allows greater control over NTA growth and enables fine-tuning of morphology. Electrochemical reduction of the NTA significantly lowers electrode resistance, thereby enhancing oxygen vacancies and leading to a two-order-of-magnitude rise in charge carrier density (from 2.20 × 1019 cm−3 to 1.03 × 1021 cm−3), as determined by Mott-Schottky analysis. The electrode exhibits a high areal capacitance of 1517 F cm−2 and a phase angle of at 120 Hz. This performance compares favorably with most carbon-based kHz supercapacitor electrodes. The upper-frequency limit of operation for the pseudocapacitor, as measured by the self-resonance frequency, is a high value of 80 kHz.
期刊介绍:
The Journal of Power Sources is a publication catering to researchers and technologists interested in various aspects of the science, technology, and applications of electrochemical power sources. It covers original research and reviews on primary and secondary batteries, fuel cells, supercapacitors, and photo-electrochemical cells.
Topics considered include the research, development and applications of nanomaterials and novel componentry for these devices. Examples of applications of these electrochemical power sources include:
• Portable electronics
• Electric and Hybrid Electric Vehicles
• Uninterruptible Power Supply (UPS) systems
• Storage of renewable energy
• Satellites and deep space probes
• Boats and ships, drones and aircrafts
• Wearable energy storage systems