Bimetallic Rechargeable Al/Zn Hybrid Aqueous Batteries Based on Al-Zn Alloys with Composite Electrolytes

Aluminum is abundant and exhibits a high theoretical capacity and volumetric energy density. Additionally, the high safety of aqueous aluminum-ion batteries makes them strong candidates for large-scale energystorage systems. However, the frequent collapse of the cathode material and passive oxide film results in the difficult development of aqueous aluminum-ion batteries. This work provides a novel battery system, namely, Al-Zn/Al(OTF)(3)+HOTF+Zn(OTF)(2)/AlxZnyMnO2 center dot nH(2)O, with a mixed electrolyte. The cathode applies MnO topology transformation to ensure that the cathode forms AlxMnO2 center dot nH(2)O. Topology transformation alters the structure of the cathode material so that Zn2+ can be intercalated into the AlxMnO2 center dot nH(2)O spinel structure to provide support for the material structure. Regarding the anode, Zn2+ in the electrolyte is deposited onto Al of the anode to produce a regional Al-Zn alloy. Zn2+ is reduced to Zn metal during discharging, which adds a platform for secondary discharge beneficial for battery capacity enhancement. This system can provide a 1.6 V discharge platform, while the first cycle discharge can reach 554 mAh g(-1), thereby maintaining a high capacity of 313 mAh g(-1) after 100 cycles. This study provides a new idea for the further development of aqueous aluminum-ion batteries (AAIBs).

Automated summary

This study introduces a novel battery system for aqueous aluminum-ion batteries (AAIBs) with a mixed electrolyte, which improves the battery capacity through cathode topology transformation and anode regional alloying. It provides new insights for the further development of AAIBs.