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

Abstract 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(NO 3 ) 2 /hexamine coordination-frameworks are employed as a precursor to prepare NiTe 2 /nitrogen-doped graphitic carbon nanosheets (NiTe 2 @NCNs) via pyrolysis and subsequent tellurization. Layered NiTe 2 nanoparticles are uniformly anchored on the carbon nanosheets. As anode materials, NiTe 2 @NCNs exhibit ultrafast and long-life Na-ion storage performance. NiTe 2 @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, NiTe 2 @NCNs exhibit minimal increasing of polarization from 0.1 to 5 A g −1 . The superior electrochemical performance of NiTe 2 @NCNs should be attributed to the two-dimensional structure, N-doped graphitic carbon matrix and lager interlayer spacing of NiTe 2 , which contribute to enhance kinetics of electron and Na-ion transfer so as to result in a capacitive-controlled Na-ion storage process. Therefore, NiTe 2 @NCNs have a promising potential as anode materials for practical Na-ion storage applications.