posted on 2022-09-07, 19:35authored byPeichao Zou, Ruoqian Lin, Travis P. Pollard, Libing Yao, Enyuan Hu, Rui Zhang, Yubin He, Chunyang Wang, William C. West, Lu Ma, Oleg Borodin, Kang Xu, Xiao-Qing Yang, Huolin L. Xin
The
rechargeability of aqueous zinc metal batteries is plagued
by parasitic reactions of the zinc metal anode and detrimental morphologies
such as dendritic or dead zinc. To improve the zinc metal reversibility,
hereby we report a new solution structure of aqueous electrolyte with
hydroxyl-ion scavengers and hydrophobicity localized in solvent clusters.
We show that although hydrophobicity sounds counterintuitive for an
aqueous system, hydrophilic pockets may be encapsulated inside a hydrophobic
outer layer, and a hydrophobic anode–electrolyte interface
can be generated through the addition of a cation-philic, strongly
anion-phobic, and OH–-reactive diluent. The localized
hydrophobicity enables less active water and less absorbed water on
the Zn anode surface, which suppresses the parasitic water reduction;
while the hydroxyl-ion-scavenging functionality further minimizes
undesired passivation layer formation, thus leading to superior reversibility
(an average Zn plating/stripping efficiency of 99.72% for 1000 cycles)
and lifetime (80.6% capacity retention after 5000 cycles) of zinc
batteries.