Hierarchical α-MnO₂@La_xMn_1-xO_2-δ core–shell nanostructure cathode for high-performance aqueous Zn-ion batteries

Rechargeable aqueous zinc-ion batteries (AZIBs) are received the extensive attention due to their high-safety, huge cost competitiveness, and eco-friendliness. However, they are still limited by advanced cathode materials in terms of cycle stability and energy density. Herein, hierarchical α-MnO₂@La_xMn_1-xO_2-δ(α-MnO₂@LMO) core–shell nanostructures are developed to improve the electrochemical performance of AZIBs. In this structure, the internal hollow nanotubes mechanically support the external La_xMn_1-xO_2-δ nanosheets, forming a porous, open, and robust electrode architecture. Benefiting from unique structure, the α-MnO₂@LMO cathode exhibits good initial specific capacity (240 mAh g⁻¹) and cyclic stability. Moreover, the α-MnO₂@LMO cathode delivers a specific capacity of 115 mAh g⁻¹ with 90% of the initial capacity after 1500 cycles at 1 A g⁻¹. The electrochemical dynamics test, charge–discharge mechanism study and phase and structure evolution analysis show that the formation of core–shell structure not only enhance the structural stability of MnO₂, alleviate the dissolution of Mn, and improve the transport kinetics of Zn²⁺, but also inhibit the irreversible ZnMn₂O₄ produced in the process of repeated H⁺ and Zn²⁺ co insertion/extraction. This study intends to provide an alternative method for the next generation cathode materials for AZIB.