Nanofibrillated Cellulose-Derived Nanofibrous Co@N-C as Oxygen Reduction Reaction Catalysts in Zn-Air Batteries

A strategy for one-dimensional nanofibrous Co@N-C oxygen reduction reaction (ORR) electrocatalysts was developed using nanofibrillated cellulose (NFC) as the scaffold material. In situ coupling of a Co-adenine (Co-Ad) complex on an NFC bio-template leads to populated and well spatial distribution of C, N, and Co active species after pyrolysis, which has a pivotal effect on facilitating ORR via a four-electron-dominated process. Additionally, the internal abundant micro- and mesopores in the carbon nanofiber skeleton ensure rapid mass transport and adequate exposure of active compositions. In combination with these advantages, the as-obtained Co-Ad/NFC-700 demonstrated superior ORR activity and endowed the fabricated Zn-air battery with superb performance: a high peak power density of 167 mW cm^-2, an excellent specific capacity of 739 mA h g^-1, and an excellent cyclability exceeding 40 h.