Cyanide‐Driven Nitrite Trapping Enables Robustly‐Coupled Gel/Cathode Interfaces in Zinc‐Air Batteries

ABSTRACT

Gel zinc‐air batteries (GZABs) are promising for flexible energy storage. However, their performance is often limited by unstable gel cathode interfaces, where water‐dependent OH ⁻ transport, charge transfer, and mechanical adhesion are closely linked. Here, we propose an interfacial coupling chemistry by using a cobalt‐based Prussian blue analogue (CCN) as a reconstructable precatalyst. When assembled with a polyvinyl alcohol (PVA) gel electrolyte and electrochemically activated during the GZAB operation, CCN was reconstructed into a sheet‐arrayed amorphous CoOOH while releasing cyanide‐derived nitrogen that was confined by the gel network and converted into −NO ₂ groups at the PVA/CoOOH interface. These NO ₂ groups act as molecular linkers, chemically coupling with CoOOH through Co–N–O bonding and reinforcing hydrogen bonding with the PVA chains. The in situ reconstructed electrode exhibits enhanced interfacial OH ⁻ transport, with an apparent diffusion coefficient 3.25 times that of the ex situ construction, together with lower interfacial resistance and stronger mechanical adhesion. Benefiting from both the reconstructed CoOOH catalyst and coupling interface, the resulting GZAB delivers a peak power density of 144 mW cm ⁻² and maintains 86.4 mW cm ⁻² even at 30% water content. The enhanced interfacial adhesion further enables stable operation in omnidirectionally flexible cable‐type zinc‐air batteries.