High Zinc Utilization Aqueous Zinc Ion Batteries Enabled by 3D Printed Graphene Arrays

The commercialization of aqueous zinc ion batteries requires good reversibility and high zinc utilization of zinc anode. For commonly applied 2D zinc anodes (zinc foils), their electrochemical performance and reversibility are often negatively correlated with the zinc utilization owing to the formation of zinc dendrites at the electrodeseparator interphase. To overcome the disadvantages of 2D geometric design of zinc anode, this work fabricated two types of 3D printing graphene arrays (3DGs), tube arrays and pilar arrays, to simultaneously improve the reversibility and utilization of zinc anodes. The highly ordered 3D printed tubes/pillars array structures can accommodate the significant volume change during the zinc reversibly deposition/dissolution process and modify the zinc deposition on 3DGs. The array structures can also buffer the interaction between the metallic zinc and separator to protect AZIBs from short circuits. Consequently, the 3DGs showed considerable columbic efficiencies at current densities of 10-80 mA cm-2. The 3DGs@Zn anode delivered a lifespan of 1100 h in zinc symmetric cell at 2 mA cm-2 (1 mAh cm-2). The pouch cells fabricated with 3DGs@Zn anodes and V2O5 cathode delivered areal capacity (3.76 mAh cm-2) and zinc utilization (47.12%) under a practical N/P ratio (1.74:1). This work will overcome the limitations of the 2D geometric design of anodes for next-generation battery technologies.