Covalently Coupled Ultrafine H-TiO2 Nanocrystals/Nitrogen-Doped Graphene Hybrid Materials for High-Performance Supercapacitor

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• 作者：Shuhua Yang ; Yuan Lin ; Xuefeng Song ; Peng Zhang ; Lian Gao
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：August 19, 2015
• 年：2015
• 卷：7
• 期：32
• 页码：17884-17892
• 全文大小：543K
• ISSN：1944-8252

文摘

Hydrogenated TiO₂ (H-TiO₂) are considered one of the most promising materials for supercapacitors given its low-cost, high conductivity, and enhanced electrochemical activity. However, the electrochemical performances of H-TiO₂ due to lacking suitable structures is unsatisfactory, and thus how to design energetic H-TiO₂-based electrode architectures still remains a great challenge. Herein, covalently coupled ultrafine H-TiO₂ nanocrystals/nitrogen-doped graphene (H-TiO₂/NG) hybrid materials were developed through a simple hydrothermal route followed by hydrogenation. Within this architecture, the strong interaction between H-TiO₂ nanocrystals and NG sheets via covalent chemical bonding affords high structural stability inhibiting the aggregation of H-TiO₂ nanocrystals. Meanwhile, the NG matrices function as an electrical highway and a mechanical backbone so that most of well-dispersed ultrafine H-TiO₂ nanocrystals are electrochemically active but stable. As a result, the optimized H-TiO₂/NG (H-TiO₂/NG-B) exhibited high reversible specific capacity of 385.2 F g^鈥? at 1 A g^鈥?, enhanced rate performance of 320.1 F g^鈥? at a high current density of 10 A g^鈥?, and excellent cycling stability with 98.8% capacity retention.