Self-Supported Cu Electrode as the Cathode for Hybrid Zn-Air/Cu Batteries Achieving Long-Term Operation Under...

The integration of Zn-air batteries with Zn-metal batteries enables the efficient realization of hybrid Zn-based batteries with synergistic high energy and power density. In this hybrid system, the reduction potential of CuO in the Zn-Cu battery is lower than the oxygen reduction reaction (ORR), thus allowing CuO to replace the ORR and enable discharging under oxygen-free conditions. Herein, carbon nanotubes are deposited onto copper foam, followed by one-step calcination process to fabricate self-supported electrode CuO_x@CNTs/CF for hybrid Zn-air/Cu batteries. The hybrid Zn-air/Cu batteries deliver the peak power density of 117.5 mW cm^-2 and specific capacity of 792.6 mAh g^-1, with a stable cycling life of 800 h. More importantly, the self-supported electrode enables stable operation for up to 340 h in oxygen-free environments. Furthermore, the introduction of NiFe-based active species to construct hybrid Zn-air/Cu/Ni batteries boosts the peak power density to an excellent 458.4 mW cm^-2. The hybrid batteries exhibit stable cycling life for 1200 h under oxygen-rich conditions and 390 h in oxygen-free environments, respectively. This work provides profound insights into the rational design, development and practical applications of hybrid Zn-based batteries for future energy storage systems.