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NC@NiMoS 4 nanocomposites have been firstly designed and fabricated by anchoring NiMoS 4 nanoparticles on N doped carbon nanosheets, which delivers high and stable reversible capacity and excellent rate performance. Owing to the excellent electrical conductivity and high theoretical capacity, binary transition metal sulfides have attracted extensive attention as promising anodes for lithium ion batteries (LIBs). However, the relatively poor electrical conductivity and serious capacity fading originated from large volume change still hinder their practical applications. Herein, binary NiMoS 4 nanoparticles are deposited on N doped carbon nanosheets (NC@NiMoS 4) through a facile hydrothermal method. The N doped carbon nanosheets and the strong chemical bonding between NC and NiMoS 4 can accommodate the volume change, keep the structural integrity and promote the ion/electron transfer during electrochemical reaction. The extra voids between NiMoS 4 nanoparticles enlarge the contact area and reduce the lithium migration barriers. As anode for LIBs, the NC@NiMoS 4 exhibits the excellent cycle stability with 834 mAh g−1 after 100 cycles at the current density of 100 mA g−1. Even at high rate of 2000 mA g−1, the specific capacity of 544 mAh g−1 can be achieved after 500 cycles. [ABSTRACT FROM AUTHOR]

The Co 0.85 Se nanosheets with the interlayer spacing of ~1.0 nm on N-doped carbon nanosheets were fabricated with the assistance of diethylenetriamine. Such unique nanostructures provide the more channels for accelerating the Li-ion transport and buffering the volume change during charge-discharge process, endowing the excellent electrochemical performance. Co 0.85 Se nanosheets assembled layer by layer on N-doped carbon nanosheets (NC@Co 0.85 Se) are designed and fabricated through a facile solvothermal process. The hexamethylenetetramine as the solvent and complexing agent promotes the accumulation of Co 0.85 Se layer by layer. The long chain diethylenetriamine between the Co 0.85 Se nanosheets provides buffer space and nanochannels for accelerating the Li+ transportation. The N-doped carbon nansheets in NC@Co 0.85 Se provide effective conductive network during charge-discharge process. As an anode material for lithium-ion batteries, the NC@Co 0.85 Se nanocomposites deliver a high specific capacity of 636 mAh g−1 after 100 cycles at current density of 200 mA g−1, and 399 mAh g−1 for 500 cycles at high current density of 5000 mA g−1. [ABSTRACT FROM AUTHOR]

Transition metal sulfides have been considered as promising anodes for lithium batteries for its high theoretical specific capacity. However, the lower conductivity, larger volume change and slower electrochemical reaction dynamics still hinder its practical applications. Here, Co 0.6 Fe 0.4 S 2 nanoparticles with metal vacancies anchored on the N-doped carbon nanosheets (NC@Co 0.6 Fe 0.4 S 2) are designed and fabricated by a facile hydrothermal method. The NC@Co0.6Fe0.4S2 delivers high reversible capacity, stable cyclability and excellent rate capacity by retaining the capacities of 830mAh g−1 after 100 cycles at 200 mA g−1 and 696mAh g−1 after 500 cycles at 5000 mA g−1. The improved electrochemical performance is attributed to the metal vacancies, N-doped carbon nanosheets and strong metal-nitrogen bonds between the Co 0.6 Fe 0.4 S 2 and N-doped carbon nanosheets, which greatly enhance charge transfer/transport and maintain structural integrity. The construction of metal vacancies along with N-doped carbon wrapping can be extended to prepare other transition metal sulfides for enhancing the electrochemical performance. Metal vacancies abundant Co 0.6 Fe 0.4 S 2 anchored on N-doped porous carbon nanosheets have been fabricated, which delivers excellent cycle stability and rate capacity. Image 1 • NC@Co 0.6 Fe 0.4 S 2 with metal vacancies is fabricated by a facile hydrothermal method. • The metal vacancies and metal-nitrogen bonds facilitate Li+ ion diffusion of the electrode. • NC@Co 0.6 Fe 0.4 S 2 exhibits excellent electrochemical performance. [ABSTRACT FROM AUTHOR]