Synergistically enhancing ion migration kinetics and inducing orientation deposition for dendrite-free aqueous zinc-ion batteries

Aqueous zinc-ion batteries (ZIBs) have garnered widespread interest owing to their merits of high safety and low cost. Nevertheless, the commercial application of ZIBs is hindered by uncontrollable dendrite growth and adverse side reactions. Herein, a potential spontaneous reducing and assembling strategy has been tailored to generate a uniform and ultra-thin layer of sulfonate modified Mxene (SM-MXene) layer on the Zn surface to regulate electrochemical behavior. Compared with the bare Zn foil, the optimizing SM-MXene layer has an advantageous charge redistribution effect, resulting in a uniform electric field and a lower Zn nucleation energy barrier. The SM-MXene layer can also block the entry of H2O and inhibit the severe side reactions. The zincophilic SM-MXene layer, possessing abundant sulfonic acid groups (- SO3H), can remarkably reduce the surface energy of the Zn (002) crystal plane and induce the preferential growth of (002) horizontally orientation during the electrodeposition process, resulting in highly reversible process between Zn plating and stripping with dendrite-free and corrosion-free behaviors. Accordingly, the symmetric battery, using SM-MXene/ZnSO4 as electrolyte, exhibits ultra-high Coulombic efficiency (99.48 %) and ultra-long cycle life (over 5000 cycles), subsequently enabling the Zn||MnO2 full cell highly rechargeable.