Semi-flowable Zn semi-solid electrodes as renewable energy carrier for refillable Zn-Air batteries

Today's society relies on energy storage on a day-to-day basis, e.g. match energy production and demand from renewable sources, power a variety of electronics, and enable emerging technologies. As a result, a vast range of energy storage technologies has emerged in the last decades. Among them, rechargeable Zn-Air batteries have held great promises for a long time. However, the severe challenges related to the reversible O-2 reactions and poor cyclability at the positive and negative electrodes, respectively, have severely hindered the success of this technology. Herein, electrically-conducting and semi-flowable Zn semi-solid electrodes are proposed to revive the appealing concept of a mechanically-rechargeable alkaline Zn-Air battery, in which the spent negative electrodes are easily substituted at the end of the discharge process (refillable primary battery). In this proof-of-concept study energy densities of ca. 1500 Wh L-1 (1350 Ah L-1 electrode and utilization rate of 85%) are achieved thanks to the compromised flowability of the proposed Zn semi-solid electrodes. In this way, semi-solid Zn electrodes become a type of green energy carrier having intrinsic advantages over gas and liquid fuels. Zn semi-flowable electrode can be generated elsewhere using renewable sources, easily stored, transported, and used to produce electricity.

Automated summary

In this study, electrically-conducting and semi-flowable zinc semi-solid electrodes were proposed for mechanically-rechargeable alkaline zinc-air batteries. High energy densities were achieved thanks to the compromised flowability of the electrodes. Zinc semi-flowable electrodes serve as a green energy carrier, which can be generated using renewable sources and easily stored, transported, and used.