Bimetallic phosphide Ni2P/CoP@rGO heterostructure for high-performance lithium/sodium-ion batteries

作者：Zhou, Hongyan; Zhao, Yanming^*; Jin, Yan; Fan, Qinghua; Dong, Youzhong; Kuang, Quan

来源：Journal of Power Sources, 2023, 560: 232715.

DOI：10.1016/j.jpowsour.2023.232715

• Ni2P
• CoP@rGO
• Heterostructure
• Li-ion batteries
• Na-ion batteries
• In-situ XRD

Transition metal phosphides hold great potential as anode materials owing to their high theoretical capacity and modest plateau, while the unstable structure and unsatisfactory reaction kinetics limited their practical appli-cations. Herein, a flower-like Ni2P/CoP@rGO heterostructures is rationally designed and used as the anode for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). The Ni2P/CoP@rGO heterostructures possesses abundant heterointerfaces, plentiful vacancies and high specific surfaces to improve Li-ion/Na-ion transport kinetics and increase reaction active sites. The introduction of graphene enhances structural stability and ac-celerates the charge transfer rate. Therefore, the Ni2P/CoP@rGO delivers an ultrahigh capacity of 196.4 mAh g-1 at 10 A g-1 after 5000 cycles for LIBs, and 103.7 mAh g-1 at 3 A g-1 after 800 cycles for SIBs. Meanwhile, the Ni2P/CoP@rGO-based Li-ion full cell can exhibit ultra-stable electrochemical performance (240.2 mAh g-1 after 40 cycles at 50 mA g-1). Furthermore, in-situ X-ray diffraction (XRD) and ex-situ characterization reveal the Li-ion/Na-ion conversion behavior within the Ni2P/CoP@rGO. This work demonstrates that rationally designing heterostructure materials is a feasible strategy for achieving high-performance energy storage.