Improving the intrinsic electronic conductivity of NiMoO₄ anodes by phosphorous doping for high lithium storage

Heteroatom doping is one of the most promising strategies toward regulating intrinsically sluggish electronic conductivity and kinetic reaction of transition metal oxides for enhancing their lithium storage. Herein, we designed phosphorus-doped NiMoO₄ nanorods (P-NiMoO₄) by using a facile hydrothermal method and subsequent low-temperature phosphorization treatment. Phosphorus doping played an indispensable role in significantly improving electronic conductivity and the Li⁺ diffusion kinetics of NiMoO₄ materials. Experimental investigation and density functional theory calculation demonstrated that phosphorus doping can expand the interplanar spacing and alter electronic structures of NiMoO₄ nanorods. Meanwhile, the introduced phosphorus dopant can generate some oxygen vacancies on the surface of NiMoO₄, which can accelerate Li⁺ diffusion kinetics and provide more active site for lithium storage. As excepted, P-NiMoO₄ electrode delivered a high specific capacity (1, 130 mAh·g⁻¹ at 100 mA·g⁻¹ after 100 cycles), outstanding cycling durability (945 mAh·g⁻¹ at 500 mA·g⁻¹ over 200 cycles), and impressive rate performance (640 mAh·g⁻¹ at 2, 000 mA·g⁻¹) for lithium ion batteries (LIBs). This work could provide a potential strategy for improving intrinsic conductivity of transition metal oxides as high-performance anodes for LIBs.