A 3D free-standing Co doped NiP nanowire oxygen electrode for stable and long-life lithium-oxygen batteries.

Exploring oxygen electrodes with superior bifunctional catalytic activity and suitable architecture is an effective strategy to improve the performance of lithium-oxygen (Li-O) batteries. Herein, the internal electronic structure of NiP is regulated by heteroatom Co doping to improve its catalytic activity for oxygen redox reactions. Meanwhile, magnetron sputtering N-doped carbon cloth (N-CC) is used as a scaffold to enhance the electrical conductivity. The deliberately designed Co-NiP on N-CC (Co-NiP@N-CC) with a typical 3D interconnected architecture facilitates the formation of abundant solid-liquid-gas three-phase reaction interfaces inside the architecture. Furthermore, the rational catalyst/substrate interfacial interaction is capable of inducing a solvation-mediated pathway to form toroidal-LiO. The results show that the Co-NiP@N-CC based Li-O battery exhibits an ultra-low overpotential (0.73 V), enhanced rate performance (4487 mA h g at 500 mA g) and durability (stable operation over 671 h). The pouch-type battery based on the Co-NiP@N-CC flexible electrode runs stably for 581 min in air without obvious voltage attenuation. This work verifies that heterogeneous atom doping and interface interaction can remarkably strengthen the performance of Li-O cells and thus pave new avenues towards developing high-performance metal-air batteries.