Abstract:
Aqueous zinc ion batteries are regarded as one of the most promising candidates for large-scale energy storage due to their high safety, cost-effectiveness, and environmental friendliness. However, the uncontrolled dendrite growth and side reactions of zinc anode compromise the stability of the batteries. Herein, an air-oxidized carbon nanotube (O-CNT) film is synthesized by chemical vapor deposition followed by a heat treatment in the air, then adopted as the protective layer to suppress the dendrite growth. The hydrophilicity regulation of the O-CNT film resulting from air oxidation facilitates the interface zinc deposition between the film and the anode instead of surface deposition on the film. Meanwhile, the conductive porous structure of the O-CNT film homogenizes the Zn
2+ flux and electric field on the surface of Zn foil, leading to uniform deposition of Zn. As a result, the O-CNT@Zn symmetric cell shows a significantly enhanced cycle stability with a lifespan of more than
3000 hours at 1 mA cm
−2 and a lifespan of more than 2000 hours even under a high current density of 5 mA cm
−2. Moreover, the O-CNT@Zn || MnVOH full cell demonstrates better rate performance compared to Zn || MnVOH cell, achieving a high discharge capacity of 194 mAh g
−1 at a current density of 8 A g
−1. In the long-term cycling test, the O-CNT@Zn || MnVOH full cell exhibits a capacity retention of 58.8% after 2000 cycles at the current density of 5 A·g
−1.