NiTe2/N-doped graphitic carbon nanosheets derived from Ni-hexamine coordination frameworks for Na-ion storage

Metal-organic-frameworks (MOFs) have recently been an emerging self-templated precursor to derive various nanomaterials for Na-ion storage. However, synthesis of MOF-derived two-dimensional nanomaterials has been rarely explored. Here, Ni(NO3)(2)/hexamine coordination-frameworks are employed as a precursor to prepare NiTe2/nitrogen-doped graphitic carbon nanosheets (NiTe2@NCNs) via pyrolysis and subsequent tellurization. Layered NiTe2 nanoparticles are uniformly anchored on the carbon nanosheets. As anode materials, NiTe2@NCNs exhibit ultrafast and long-life Na-ion storage performance. NiTe2@NCNs can deliver a reversible capacity of 289.5 mA h g(-1) at 0.1 A g(-1) and exhibit a negligible capacity fading with the increasing of current density from 0.1 to 10 A g(-1). Even at 10 and 20 (ca. 70 C) A g(-1), reversible capacities remain at 267.7 and 189.0 mA h g(-1), respectively, and cyclic life can be up to 5000 cycles. Besides, NiTe2@ NCNs exhibit minimal increasing of polarization from 0.1 to 5 A g(-1). The superior electrochemical performance of NiTe2@ NCNs should be attributed to the two-dimensional structure, N-doped graphitic carbon matrix and lager interlayer spacing of NiTe2, which contribute to enhance kinetics of electron and Na-ion transfer so as to result in a capacitivecontrolled Na-ion storage process. Therefore, NiTe2@NCNs have a promising potential as anode materials for practical Na-ion storage applications.