Flexible electrode of NiTe 2 /porous graphene film as binder-free anode for lithium-ion batteries

Abstract The NiTe 2 nanocrystals anchored on porous graphene films (NiTe 2 @PG) were fabricated through a sequential process involving vacuum filtration, annealing, and tellurization. Within this structure, the NiTe 2 nanocrystals formed via the confined growth of NiTe 2 nanoparticles. The morphology and structure of the NiTe 2 @PG composite was examined by scanning electron microscopy, transmission electron microscopy, and x-ray diffraction, while the interfacial interaction between NiTe 2 and graphene was investigated by x-ray photoelectron spectroscopy and Raman spectroscopy. When evaluated as an anode material for lithium-ion batteries, the NiTe 2 @PG electrode delivered an initial reversible capacity of 875.7 mAh g −1 at a current density of 100 mA g −1 . Furthermore, it exhibited outstanding long-term cyclability, retaining specific capacities of 243.5 and 135 mAh g −1 after 10 000 cycles at high current densities of 2 and 5 A g −1 , respectively. This remarkable electrochemical performance was attributed to the unique architecture of NiTe 2 @PG and the robust covalent bonding at the graphene/NiTe 2 interface. The porous graphene scaffold serves not only as a conductive substrate for the growth of NiTe 2 nanocrystals but also facilitates electron transport. Concurrently, its porous network shortened the diffusion path for Li + ions and enhanced electrolyte permeability. Moreover, the formation of C–Te–Ni covalent bonds between graphene and NiTe 2 played a crucial role in maintaining the structural integrity of the electrode during cycling.