A mesoporous Al2O3 zincophilic sieve enables ultra-long lifespan of Zn-ion batteries

The Zn dendrite growth and side reactions hinder the practical application of aqueous Zn-ion batteries. Here, a lactic acid-induced mesoporous Al2O3 (LA-MA) zincophilic sieve was constructed on a Zn anode to resolve these issues. The LA-MA layer with abundant mesoporous ion channels of 3.0 nm can regulate the solvation structure from [Zn2+(H2O)6]SO42- to more highly coordinated [Zn2+(H2O)5OSO32-] and restrain water-induced side reactions. Furthermore, the electrostatic attraction with zincophilic groups (CO, C-O) in the LA-MA layer has a positive effect on reducing the Zn2+ desolvation barrier and accelerating the Zn2+ diffusion. Under the synergism, the LA-MA@Zn symmetric cell exhibits over 5100 h at 0.25 mA cm-2. Impressively, an excellent capacity retention of 94.2% is achieved after 3500 cycles for the CNT/MnO2 cathode.