High-Energy and High-Power Pseudocapacitor-Battery Hybrid Sodium-Ion Capacitor with Na+ Intercalation Pseudocapacitance Anode

• 作者: Qiulong Wei Qidong Li Yalong Jiang Yunlong Zhao Shuangshuang Tan Jun Dong Liqiang Mai Dong?Liang Peng
• 来源期刊: 纳微快报（英文）
• 年，卷（期）: 2021,（3）
• 页码范围: 209-221
• 页数: 13页
• 语种: 英文

摘要

High-performance and low-cost sodium-ion capacitors (SICs) show tremendous potential applications in public transport and grid energy storage. However, conventional SICs are limited by the low specific capac-ity, poor rate capability, and low initial coulombic Efficiency (ICE) of anode materials. Herein, we report layered iron vanadate (Fe5V15O39 (OH)9·9H2O) ultrathin nanosheets with a thickness of ～ 2.2 nm (FeVO UNSs) as a novel anode for rapid and reversible sodium-ion storage. According to in situ syn-chrotron X-ray diffractions and electrochemical analysis, the storage mechanism of FeVO UNSs anode is Na+ intercalation pseudocapacitance under a safe potential window. The FeVO UNSs anode delivers high ICE (93.86％), high reversible capacity (292 mAh g-1), excellent cycling stability, and remarkable rate capability. Furthermore, a pseudocapacitor-battery hybrid SIC (PBH-SIC)consisting of pseudocapacitor-type FeVO UNSs anode and battery-type Na3(VO)2(PO4)2F cathode is assembled with the elimination of presodiation treatments. The PBH-SIC involves faradaic reaction on both cathode and anode materials, delivering a high energy density of 126 Wh kg-1 at 91 W kg-1, a high power density of 7.6 kW kg-1 with an energy density of 43 Wh kg-1, and 9000 stable cycles. The tunable vanadate materials with high-performance Na+ intercalation pseudocapacitance provide a direction for developing next-generation high-energy capacitors.