Single-Atom Catalyst with Optimized Ni Content in a Flexible Zn-Air Battery Operated at a Wide Temperature Range

Flexible and safe energy storage systems are critical for the advancement of wearable and portable electronics. Although lithium-ion batteries dominate the market, their reliance on flammable electrolytes and rigid structures limits their use in flexible applications. Herein, we report the development of a flexible Zn-air battery featuring a nitrogen-doped lamellar carbon cathode embedded with Ni single-atom catalytic sites. The battery demonstrated a high areal capacity of ∼32 mA·h cm^-2 and sustained stable operation over nearly 325 charge-discharge cycles. It also achieved a maximum discharge current density of 150 mA cm^-2 under the polarization conditions. In the half-cell configuration, the optimized Ni-N_x catalyst exhibited a low overpotential of 1.45 V vs. RHE at 10 mA cm^-2 for the oxygen evolution reaction, outperforming the benchmark IrO₂ catalyst (1.49 V vs. RHE). The full cell maintained excellent electrochemical stability across a broad temperature range (5-60 °C) and retained its functionality under severe mechanical deformation, including bending, cutting, and puncturing. Postcycling SEM analysis revealed the formation of vertically aligned Zn nanostructures that effectively suppressed dendrite growth.