A flexible carbon nanotube@V2O5 film as a high-capacity and durable cathode for zinc ion batteries

Abstract

A highly flexible composite film composed of carbon nanotube film and V 2 O 5 with high strength and high conductivity is prepared by simply impregnating a porous CNT film with an aqueous V 2 O 5 sol. Aqueous zinc-ion batteries (ZIBs) are receiving a continuously increasing attention for mobile devices, especially for the flexible and wearable electronics, due to their non-toxicity, non-flammability, and low-cost features. Despite the significant progress in achieving higher capacities for electrode materials of ZIBs, to endow them with high flexibility and economic feasibility is, however, still a significant challenge remaining unsolved. Herein, we present a highly flexible composite film composed of carbon nanotube film and V 2 O 5 (CNTF@V 2 O 5 ) with high strength and high conductivity, which is prepared by simply impregnating a porous CNT film with an aqueous V 2 O 5 sol under vacuum. For this material, intimate incorporation between V 2 O 5 and CNTs has been achieved, successfully integrating the high zinc ion storage capability with high mechanical flexibility. As a result, this CNTF@V 2 O 5 film delivers a high capacity of 356.6 mAh g −1 at 0.4 A g −1 and excellent cycling stability with 80.1% capacity retention after 500 cycles at 2.0 A g −1 . The novel strategy and the outstanding battery performance presented in this work should shed light on the development of high-performance and flexible ZIBs.