Enabling highly efficient, flexible and rechargeable quasi-solid-state zn-air batteries via catalyst engineering and electrolyte functionalization

Flexible Zn-air battery (ZAB) depicts promising prospects for the eventual realization of next-generation flexible electronic devices. However, developing such flexible power sources with high efficiency and durability remains a great challenge, largely due to the low effectiveness of the key components within the ZAB configuration. Herein, we demonstrate an efficient, flexible and rechargeable ZAB by integrating an active Co-N-C reversible electrocatalyst and a highly conductive alkalined polyacrylate hydrogel. The active sites for the oxygen reduction and evolution reactions (ORR-OER) within the catalyst are carefully identified and facily tuned, enabling the engineered catalyst to deliver much better bifunctional activities than the noble-metal counterparts yet with only approximately 7% cost of the latter. The alkalined hydrogel affords preeminent ionic conductivity and water retention capability, well satisfies the role for solid-state electrolyte. Impressively, the thus fabricated solid-state flexible ZAB exhibits an open circuit voltage of 1.45 V, a peak power density of 144.6 mW cm⁻², a round trip efficiency of 62%, a stable rechargebility for over 400 cycles at 2 mA cm⁻² along with excellent flexibility, which even outperform those from many aqueous ZABs, highlighting its great potential as flexible power source for next-generation electronics.