context: We have successfully synthesized a self-supported CoFe@NCNT/CFC electrode for mechanically flexible ZABs, through a facile strategy. The optimized CoFe@NCNT/CFC cathode shows excellent bifunctional electrocatalytic activities with a half-wave potential of 0.873 V for the ORR and E10 = 1.506 V for the OER. The flexible all-solid-state ZABs with the CoFe@NCNT/CFC cathode exhibit a large open-circuit voltage of 1.426 V and a large power density of 37.7 mW cm−2 as well as robust stability. More importantly, ZABs assembled with the self-supported CoFe@NCNT/CFC cathode can still work even under extreme bending conditions. Our strategy opens a new way for flexible self-supported catalysts for high-performance portable and rechargeable energy storage devices.
answer: CoFe@NCNT/CFC