A novel layered cobalt oxide Ba 2 Co 9 O 14 as an efficient and durable bifunctional oxygen electrocatalyst for rechargeable zinc-air batteries

In this work, a layered cobalt oxide Ba 2 Co 9 O 14 (BCO), belongs to a Ba n+1 Co n O 3n+3 (Co8O8) family composed by alternating CdI 2 based layers (Co8O8) with n (111) perovskite blocks (Ba n+1 Co n O 3n+3 ), has been developed as a potential bifunctional oxygen electrocatalyst candidate for efficient and durable rechargeable zinc -air battery (ZAB) application. Because of the greatly increased the specific surface area caused by ball-milling, the as-milled BCO material exhibits strongly enhanced bifunctional electrocatalytic activity towards oxygen reduction and oxygen evolution reaction in alkaline medium. Moreover, the assembled BCO-based ZAB yields an effectively improved maximum output power density of 166 mW cm -2 , a considerable specific capacity of 789 mAh g -1 , and excellent charge-discharge cycle stability of over 250 h at 10 mA cm -2 with over 1500 cycles.