Highly reversible Zn metal anode enabled by sustainable hydroxyl chemistry

Abstract

Rechargeable Zn metal batteries (RZMBs) may provide a more sustainable and lower-cost alternative to established battery technologies in meeting energy storage applications of the future. However, the most promising electrolytes for RZMBs are generally aqueous and require high concentrations of salt(s) to bring efficiencies toward commercially viable levels and mitigate water-originated parasitic reactions including hydrogen evolution and corrosion. Electrolytes based on nonaqueous solvents are promising for avoiding these issues, but full cell performance demonstrations with solvents other than water have been very limited. To address these challenges, we investigated MeOH as an alternative electrolyte solvent. These MeOH-based electrolytes exhibited exceptional Zn reversibility over a wide temperature range, with a Coulombic efficiency > 99.5% at 50% Zn utilization without cell short-circuit behavior for > 1,800 h. More important, this remarkable performance translates well to Zn || metal-free organic cathode full cells, supporting < 6% capacity decay after > 800 cycles at −40 °C.

Electrolyte Modulation Strategies for High Performance Zinc Batteries

“…It is confirmed that a highly reversible Zn deposition behavior of Zn metal (≥99.0 %) and high anodic stability (∼3.6 V vs. Zn) is achieved in organic electrolytes, e. g., (acetonitrile) AN−Zn(TFSI) 2 , [23] AN−Zn(CF 3 SO 3 ) 2 , [24] DMC‐TMP−Zn(TFSI) 2 (dimethyl carbonate‐trimethyl phosphate) [25] . Recently, Xu et al [26] . have discovered a class of nonaqueous but protic solvent based on the alcohol family.…”

Aqueous all-manganese batteries

“…26–29 Although metal anodes such as Al and Mg have low theoretical redox potentials, it is very difficult to realize their highly reversible deposition and dissolution in aqueous electrolytes. 6,30 Moreover, they typically showed high polarization and passivation, which lead to much higher redox potentials than their theoretical values. 18,20 Therefore, it is of great significance to explore new aqueous metal anodes to construct high voltage aqueous metal batteries.…”

“…[44][45][46] The continuous outgassing of water during battery cycling or idling not only reduces Coulombic efficiency (CE), but also poses a serious safety concern. It is generally believed that the formation of an SEI layer will inhibit the decomposition of water and may increase the working potential of aqueous batteries, but it is very challenging to realize an AAMB with a voltage as high as 2.42 V. 6,8,30 It was demonstrated that the MnO 2 cathode in MnO 2 /Mn 2+ chemistry with a redox potential of 1.23 V vs. SHE showed excellent electrochemical performance in aqueous electrolytes. [38][39][40] The main problem is therefore focused on the reversibility of plating/stripping reactions of Mn/Mn 2+ on the Mn metal anode in aqueous solutions.…”

Suppression of Vanadium Oxide Dissolution via Cation Metathesis within a Coordination Supramolecular Network for Durable Aqueous Zn‐V2O5 Batteries

“…[ 5a,5b ] On the other hand, the zinc anode parasitic reacts with water and the growth of the zinc dendrite, resulting in the low coulombic efficiency (CE) and continuous electrolyte consumption. [ 2b,6 ]…”