▎ 摘　　要

Batteries based on Zn and other two-valent metals can be nearly ideal charge storage devices because of their high energy density combined with reliability, earth-abundance, and low flammability. Searching for high-performance positive electrodes with good rate capability and adequate cycle life is currently a hot topic and a great challenge for developing zinc batteries. Here, a binder-free 3D porous graphene aerogel-supported alpha-Mno(2) cathode (G-Mno(2)) is synthesized via a facile and scalable hydrogel method. The hybrid cathode of alpha-Mno(2) nanotube attached on highly conductive interconnected graphene frameworks enables rechargeable Zn/G-MnO2 batteries with a high capacity of 321 mAhg(-1) at 0.2C (1C = 240 mAhg(-1)), good rate capability, and ultralong cycle life (91% capacity retention over 300 cycles at a high current rate 3C). These findings open the pathway to a large family of lowcost high-performance Zn-batteries and potentially other two-valent metals for a wide range of applications.