Freestanding strontium vanadate/carbon nanotube films for long‐life aqueous zinc‐ion batteries
Yehong Du, Xianyu Liu, Xinyu Wang, Juncai Sun, Qiongqiong Lu, Jianzhi Wang, Ahmad Omar, Daria Mikhailova
Abstract
Abstract Aqueous rechargeable zinc‐ion battery (ZIB) is considered to be a potential energy storage system for large‐scale applications due to its environmental friendliness, high safety, and low cost. However, it remains challenging to develop suitable cathode materials with high specific capacity and long‐term cyclic stability. Herein, we have fabricated freestanding Sr 0.19 V 2 O 5 ·1.3H 2 O/carbon nanotubes (SrVO/CNTs) composite films with different mass ratios by incorporating SrVO into CNTs network. The synthesized SrVO possesses a large interlayer spacing of 1.31 nm, which facilitates Zn 2+ diffusion. Furthermore, the SrVO/CNTs composite film with conductive network structure promotes electron transfer and ensures good contact between SrVO and CNTs during the long‐term cycling process. As a result, the battery based on the SrVO/CNTs composite cathode with a mass ratio of 7:3 delivers a specific capacity of 326 mAh·g −1 at 0.1 A·g −1 and 145 mAh·g −1 at 5 A·g −1 , demonstrating a high capacity and excellent rate capability. Remarkably, the assembled ZIB shows good capacity retention of 91% even after ultra‐long cycling for 7500 cycles at a high current rate of 5 A·g −1 . More importantly, the battery also delivers a high energy density and power density, as 290 Wh·kg −1 at 125 W·kg −1 (0.1 A·g −1 ), or 115 Wh·kg −1 at 6078 W·kg −1 (5 A·g −1 ). The results demonstrate that the SrVO/CNTs composite is a promising cathode toward large‐scale energy storage applications.