Modifying the Zn anode with carbon black coating and nanofibrillated cellulose binder: A strategy to realize dendrite-free Zn-MnO2 batteries.

Aqueous zinc-ion batteries have received significant attention due to their low cost and high safety. However, the unsatisfactory cycling performances caused by the dendritic growth on the Zn anode limit their practical applications. Herein, we propose to modify the conventional Zn foil anode by using carbon black coating and nanofibrillated cellulose binder. The carbon black can form an electrically conductive network, thus greatly enlarging the electroactive surface area, while the nanofibrillated cellulose can act as an electrolyte reservoir to facilitate charge transports. Thanks to that, the modified anode can significantly eliminate the dendritic growth and side reactions, therefore ensuring excellent interface stability with the electrolyte even at a commercial-level areal capacity of 5 mAh g-1. With the modified anode, the Zn-MnO2 battery gives a high capacity retention of 87.4% after 1000 cycles, much higher than that with the unmodified Zn foil (42.6%). This study discloses a facile, scalable, and cost-effective strategy to achieve dendrite-free metal electrodes towards great cyclability.