| The lithium-ion battery(LIB)has been regarded as a priority candidate in powering portable electronics due to their outstanding properties such as high energy density,long cycle life and environmental benignity.Graphite is used as commercialized anode materies for LIB mainly at present.Hower,one of the biggest problems faced by graphite anode is its low capacity(372 m Ah·g-1).Compared to carbon/graphite-based materials,Transition metal dichalcogenides(TMDs)WS2,Mo Se2 with graphene-like layered structures possess higher theoretical capacities and larger interlayer spacing and has been considered as a promising anode candidate for Li-ion batteries.Meanwhile,compared to the powder,nanosheets possess more active sites and shorter Li-ion diffusion pathways.However,these nanosheets are inclined to restack and poor charge transport kinetics,leading to a frustrating loss in the electrochemical performances and electrocatalytic activity in HER.Here we propose a facile and elegant self-organization strategy to decorate WS2,Mo Se2 nanosheets with Ag nanoparticles based on van der Waals interactions,resulting in novel zero/two dimensional heterostructures.The resulting heterostructures exhibit synergistic superiorities in electrochemical performance over neat WS2,Mo Se2 nanosheets.The main contents of this paper are as follows:(1)The WS2 namosheets and different percentages of Ag/WS2 composite materials were fabricated and the electrochemical performance of the anode materials for lithium ion batteries was studied.The composite materials exhibit a high specific capacity of 521.3 m Ah·g-1 at 100 m A·g-1,excellent rate capability(266.6 m Ah·g-1 at a high current density of 2000 m A·g-1)and great cycling stability with a capacity retention of 96% and 91% after 150 cycles at 500 m A·g-1 and 1000 m A·g-1 after 700 cycles respectively.The capacity is 443.2 m Ah·g-1 and 415.5 m Ah·g-1 respectively.(2)The Mo Se2 namosheets and different percentages of Ag/Mo Se2 composite materials were fabricated as lithium ion anode materials,Ag/Mo Se2 composite materials can achieve a stable reversible capacity and a high rate capability which exhibits a high reversible discharge capacity of 443.2 m Ah·g-1 after 100 cycles at 100 m A·g-1 and when the current density is increased to 500 m Ah·g-1 after 500 cycles,there is still a reversible capacity of 415.5 m Ah·g-1,and the capacity retention rate is 96%.As an electrocatalytic hydrogen storage material,the overpotential is 182 m V at a current density of 10 m A·cm-2,and the Tafel slope is 80.3 m V·dec-1,which shows better electrocatalytic activity in HER than the bulk materials.The excellent electrochemical properties benefit from the following aspects:(1)the two-dimensional nanosheets can not only contribute higher theoretical specific capacity as the main material,but also release the stress during charge-discharge process and inhibit the agglomeration of zero-dimensional nanoparticles according to their structural features,(2)the introduction of Ag is not only expected to allow for efficient electron transport from the current collector to the electrode but also isolate the stacking of these nanosheets through doping on the surface of nanosheets.Finally,a significant increase in cycle stability and rate performance of the composite material was achieved.In summary,this paper successfully achieved self-assembly of WS2,Mo Se2 nanosheets and Ag nanoparticles through a simple and effective method,and improved the electrochemical performance of the materials. |
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