Synergistically enhancing the selective adsorption for crystal planes to regulate the (002)-texture preferred Zn deposition via supramolecular host-guest units

Abstract

Uncontrollable dendrite growth and parasitic reactions lead to poor reversibility of zinc (Zn) anodes, which seriously hinders the commercialization of aqueous Zn metal batteries. A promising strategy to address these issues is to rationally regulate the preferred orientation of crystal planes and form compact layers during the deposition process. Herein, the host-guest interaction in supramolecular chemistry is reported to induce (002)-texture preferred Zn deposition. It is demonstrated that the supramolecular complex units synergistically enhance the selectivity and adsorption ability for Zn crystal planes, facilitating homogeneous Zn(002) deposition at high current densities and areal capacities. Meanwhile, the steric hindrance at the interface of the order-anchored supramolecular complex units on the Zn surface not only constructs a water-poor microenvironment to effectively inhibit aggressive side reactions, but also functions as an ionic buffer zone to moderate the rapid electrochemical redox kinetics, thus homogenizing the ionic fluid and electric field. Benefitting from the above advantages of the supramolecular complex units, the assembled Zn symmetric cell exhibits remarkable cycling stability (5800 h, equal to 241 days). In the cyclic-intermittent testing mode, the symmetric cell still operates stably with a cumulative resting time of 1750 h, showing an exceptional anti-calendar aging performance. Furthermore, the assembled Zn/MnO2 pouch cell achieves a long lifespan (1000 cycles at 1 A g−1) with a capacity retention of 84.9%. Therefore, this strategy of constructing supramolecular complex units to regulate the crystal orientation is expected to shed new light on aqueous battery chemistry.