Catalytic host material of NbSe2@f-Nb2C heterostructure with built-in electric field for high performance aqueous Cu-Se battery

Aqueous copper-selenium (Cu-Se) battery based on conversion mechanism have garnered interest due to their intrinsic safety features and high specific capacity. However, the slow conversion kinetics presents a challenge for its development. Herein, catalytic host material of NbSe 2 @few-layered Nb 2 C (NbSe 2 @f-Nb 2 C) heterostructure with built-in electric field (BIEF) is prepared by in situ selenization strategy for aqueous Cu-Se battery. Benefiting from the high electrical conductivity of f-Nb 2 C MXene, the high electrocatalytic performance of NbSe 2 and the spontaneous BIEF between NbSe 2 and f-Nb 2 C MXene, the Se redox reactions kinetics is enhanced and the reaction barrier is reduced. Consequently, the specific capacity of Se/NbSe 2 @f-Nb 2 C cathode can reach 1128 mAh g −1 at 0.25 A g −1 with stable cycling performance. Additionally, the conversion mechanism is investigated via comprehensive characterizations and density functional theory calculations. This study provides an innovative approach for designing high performance MXene-based catalytic host materials to enhance the conversion kinetics of aqueous Cu-Se batteries.