Metal-free, active nitrogen-enriched, efficient bifunctional oxygen electrocatalyst for ultrastable zinc-air batteries

Abstract

The availability of efficient, low-cost and durable oxygen electrocatalyst for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is the prerequisites for large-scale,practical application of rechargeable zinc (Zn)-air batteries. Thus, stable electrocatalysts with high oxygen electrocatalytic activity are in highly demand. Low-cost and metal-free carbon-based bifunctional oxygen electrocatalysts are regarded as promising alternatives to the commercially used noble metals which suffer from multiple drawbacks, including poor stability, high cost and susceptibility to methanol. Here, a facile and scalable strategy was introduced to fabricate porous carbon matrix doped with high content of active nitrogen species as efficient bifunctional oxygen electrocatalyst for superior Zn-air battery. Notably, the obtained electrocatalysts exhibit an ultrahigh surface area of 1200.3 ​m2 ​g−1 and abundant defects, both of which are capable to facilitate the accessibility and formation of catalytic sites. The as-fabricated Zn-air batteries achieve significantly large peak power density of ~160 ​mW ​cm−3 and excellent cycling performance (nearly 1000 cycles) with small voltage gap of 0.97 ​V. This research opens novel avenue for the design and fabrication of affordable high-performance oxygen electrocatalyst and durable energy storage systems.