Neodymium ion-incorporated electrolyte additive: Inducing electrostatic shielding and directed deposition to achieve high-performance zinc anodes

Aqueous zinc-ion batteries (AZIBs) are facing challenges of severe parasitic side reactions and uncontrolled Zn dendrite growth in promoting commercial applications. Here, rare earth metal neodymium ions (Nd3+) have been introduced into the conventional ZnSO4 electrolyte as an electrolyte additive to improve the stability and reversibility of AZIBs. Combining experimental characterization and theoretical calculations, Nd3+ ions are adsorbed at the active sites of zinc crystal growth, forming a positively charged shielding layer on the Zn anode surface that effectively prevents lateral reactions and induces uniform Zn deposition. Meanwhile, Nd3+ ions preferentially adsorb on (100) and (101) planes of Zn, thus facilitating preferential deposition on the (002) plane and achieving a dendrite-free Zn anode. Consequently, a Zn//Zn symmetric cell with the Nd3+-modified electrolyte exhibits an ultralong lifespan of 3000 h at 0.5 mA cm−2, and a Zn//Cu asymmetric cell realizes an impressive Coulombic efficiency of 99.47% for Zn stripping and plating over 550 cycles at 1.0 mA cm−2. Impressively, Zn//CNT@MnO2 full cell reaches a considerably stable long cycle performance over 2500 cycles at 1.0 A g−1. This work offers an effective solution to the challenges faced by Zn anode and expands the application scope of metallic ions in metal-based energy storage devices.