Electrodepositing amorphous molybdenum oxides for aqueous NH 4 + 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 NH 4 + 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 NH 4 + storage performances, offering new understanding for rational design of MoO x materials for energy storage applications.