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

The NiTe₂nanocrystals anchored on porous graphene films (NiTe₂@PG) were fabricated through a sequential process involving vacuum filtration, annealing, and tellurization. Within this structure, the NiTe₂nanocrystals formed via the confined growth of NiTe₂nanoparticles. The morphology and structure of the NiTe₂@PG composite was examined by scanning electron microscopy, transmission electron microscopy, and x-ray diffraction, while the interfacial interaction between NiTe₂and graphene was investigated by x-ray photoelectron spectroscopy and Raman spectroscopy. When evaluated as an anode material for lithium-ion batteries, the NiTe₂@PG electrode delivered an initial reversible capacity of 875.7 mAh g^-1at 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^-1after 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 NiTe₂@PG and the robust covalent bonding at the graphene/NiTe₂interface. The porous graphene scaffold serves not only as a conductive substrate for the growth of NiTe₂nanocrystals 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 NiTe₂played a crucial role in maintaining the structural integrity of the electrode during cycling.