Binder-Free Freestanding 3D Zn-Graphene Anode Induced from Commercial Zinc Powders and Graphene Oxide for Zinc Ion Battery with High Utilization Rate

Abstract

Aqueous zinc-ion batteries (AZIBs) have received widespread attention owing to the increasing demand for safety and inexpensive batteries. However, a zinc metal anode suffers from dendrite growth during continuous cycling, and side reactions occurred on anode surface such as hydrogen evolution reaction (HER) and passivation. Moreover, the low utilization of Zn metal is also a neglected issue leading to a low energy density at the cell-level. Herein, a nondendrite Zn anode with high utilization was designed by spontaneous reaction of commercial Zn powders and graphene oxide (GO). The formed binder-free three-dimensional (3D) anode Zn_G achieves a cycling time over 550 h and extremely low voltage hysteresis of ∼20 mV with 7.4% DOD (130 h for Zn foil with 1.3% DOD and 80 h for Zn powders with 7.4% DOD) at a current density of 1 mA cm–2 in a symmetric cell. In Zn||MnO2 full batteries, Zn_G greatly enhances the gravimetric energy density on the cell level and achieved more than 1600 cycles much higher than Zn foil (Zn_F) with 700 cycles and Zn powders (Zn_P) with 500 cycles. The low N/P ratio of 3 also achieved high stability with 126 mAh g–1 and 74.5% retention after 1000 cycles.