Ultra-long-life and highly reversible Zn metal anodes enabled by a desolvation and deanionization interface layer

Abstract

The zinc metal anode in aqueous zinc-ion batteries (AZIBs) is considerably impeded by uncontrollable dendrite growth and intricately water-induced corrosion, leading to low Coulombic efficiency (CE) and limited lifespan. Herein, a bifunctional cellulose nanowhisker-graphene (CNG) membrane was constructed to mitigate these problems. Experimental analysis and molecular dynamics simulation reveal that the CNG membrane, functioning as a desolvation layer to preclude H₂O molecules encountering the Zn anode, retards the water-induced corrosion reaction. This CNG layer with negative surface charges can simultaneously generate a deanionization shock by spreading cations but screening anions to obtain redirected Zn deposition parallel to the (0002)_Zn plane. Furthermore, the flexible and toughened CNG membrane could withstand a strong tensile force (8.54 N) and a great puncture force (0.10 N) to favorably accommodate the Zn anode surface fluctuation during plating/stripping. Accordingly, CNG/Zn anode delivers an enhanced CE (99.4%) and a longer cycle life (∼5500 h), over 27 times that of a bare Zn anode. A full MnO₂/graphene-CNG/Zn battery exhibits a high discharge capacity (307 mA h g⁻¹) and maintains a high capacity retention of 87.8% at 5C after 5000 cycles.