An integrated oxygen electrode derived from flexible single-wall carbon nanotube film for rechargeable Zn-Air batteries produced by electro-polymerization

The development of low-cost, high-activity, and durable integrated bifunctional flexible air electrodes for use in Zn-Air batteries is both challenging and needed. We report a simple and scalable electro-polymerization method to prepare an electrode material of heavily N-doped carbon covering single-wall carbon nanotube (N/C-SWCNT) networks. The resulting core/shell structure hybrid electrode has the flexibility, mechanics, and three-dimensional interconnected porous structure of SWCNT films while containing abundant pyridinic N, which gives it excellent catalytic activity for both the oxygen reduction and evolution reactions (overpotential gap = 0.76 V). A binder-free Zn-Air battery using the N/C-SWCNT film as an oxygen electrode was assembled and showed a high peak power density of 181 mW/cm2, a high specific capacity of 810 mAh/g and stable discharge-charge cycling ability. We also constructed a flexible solid-state Zn-Air battery with not only a high power density of 22 mW/cm2, but also good flexibility and stability.