Flexible electrode of NiTe2/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.