▎ 摘　　要

A major drawback of alpha-MnO2-based zinc-ion batteries (ZIBs) is the poor rate performance and short cycle life. Herein, an oxygen-deficient alpha-MnO2 nanotube (VO-alpha-MnO2)-integrated graphene (G) and N, P codoped cross-linked porous carbon nanosheet (CNPK) composite (VO-alpha-MnO2/CNPK/G) has been prepared for advanced ZIBs. The introduction of VO in MnO2 can decrease the value of the Gibbs free energy of Zn2+ adsorption near VO (ca. -0.73 eV) to the thermal neutral value. The thermal neutral value demonstrates that the Zn2+ adsorption/ desorption process on VO-alpha-MnO2 is more reversible than that on alpha- MnO2. The as-made Zn/VO-alpha-MnO2 battery is able to deliver a large capacity of 305.0 mAh g(-1 )and high energy density up to 408.5 Wh kg(-1). The good energy storage properties can be attributed to VO. Additionally, the VO-alpha-MnO2/CNPK/G composite possesses the structure of nanotube arrays, which results from the vertical growth of alpha-MnO(2 )nanotubes on CNPK. This unique array structure helps to realize fast ion/electron transfer and stable microstructure. The electrochemical performance of VO-alpha-MnO2 has been comprehensively improved by compositing with G and CNPK. The VO-alpha-MnO2/CNPK/G can achieve capacity up to 405.2 mAh g(-1), energy density of 542.2 Wh kg(-1), and long cycle life (80% capacity retention after 2000 cycles).