Binder-Free V2O5-Carbon Nanotube Composite Films for High-Performance Aqueous Manganese-Ion Batteries

Abstract

Aqueous manganese-ion batteries (MIBs) are distinguished as a possible choice for energy storage systems since the Mn anode could offer superior theoretical capacity and low redox potential. However, the capacities of cathode materials are usually limited by the large radius of solvated Mn2+. Herein, binder-free V2O5-carbon nanotube film (VO-CNT) cathodes were designed through a straightforward suction filtration method. In the films, V2O5 with open layered framework is desired to provide abundant ion transfer channels. More excited, the VO-CNT cathodes allow the co-intercalation/extraction of Mn2+ and H+ ions. Such charge storage mechanism significantly optimizes the electrochemical performance of the batteries. In addition, the carbon nanotubes form a continuous high-conductive scaffold in the film, which could contribute to good conductivity of the whole cathode. Leveraging the synergistic advantages of V2O5 and carbon nanotubes, the binder-free VO-CNT cathodes display a high capacity, exceptional rate capability, and robust cycling stability, retaining 96% capacity over 1000 cycles. This work will open new avenues to design outstanding-performance cathodes for aqueous MIBs.