Electrodepositing amorphous molybdenum oxides for aqueous NH₄⁺ storage

The limited choice of anode materials always challenges the development of high performance aqueous ammonium-ion batteries (AAIBs). Herein, we fabricate amorphous molybdenum oxide (MoO_x) materials and study the NH₄⁺ storage performances. The results indicate that the optimized electrode exhibits high gravimetric/areal capacities of 175 mA h g⁻¹/1.30 mA h cm⁻², outperforming state-of-the-art anode materials for AAIBs. Our findings indicate that the valence state of Mo and the Mo–O–H content in MoO_x synergistically control the NH₄⁺ storage performances, offering new understanding for rational design of MoO_x materials for energy storage applications.