The practical deployment of aqueous zinc–metal batteries (AZMBs) is hindered by Zn anodes, such as uncontrolled dendrite growth and water-induced side reactions. While monofunctional additives have achieved some successes, they ultimately fail to provide the long-term stability of Zn anodes. Herein, we introduce a zwitterionic 3-morpholinopropanesulfonic acid (3-Mor) molecule as a multifunctional electrolyte additive. First, instead of entering the Zn2+ solvation shell directly, 3-Mor operates by reconstructing the hydrogen-bond network within the bulk H2O, reducing the activity of H2O. Second, the sulfonate group and morpholine ring of 3-Mor enable specific adsorption onto the Zn surface, forming a water-deficient electric double layer (EDL) that guides Zn2+ deposition onto the (002) plane to suppress dendrite growth. Third, the intrinsic zwitterionic character of 3-Mor enables dynamic buffering of interfacial pH fluctuations, maintaining a stable interfacial microenvironment. As a result, Zn//Zn symmetric cells achieve an extended cycling lifetime of 3000 h at 1 mA cm–2, and the Zn//Ca0.24V2O5·0.83H2O full cell retains a capacity of 63.0 mAh g–1 after 7000 cycles. This work demonstrates a holistic interfacial molecular engineering strategy for achieving highly reversible Zn anodes through multifunctional modulation.
Lu et al. (Tue,) studied this question.