Preparation of heterostructured BiCoS3-δ@Co1-xS fibers as anode materials in lithium-ion batteries
Metal sulfides(MSs)have been extensively studied in lithium-ion batteries owing to their high theo-retical capacity.However,their broad utilization is severely hindered by their poor conductivity and large volu-metric change during cycling.One strategy for enhancing the electrochemical performance of MSs anode materi-als is proposed here,based on the defect engineering and heterostructure design.BiCoS3-δ fibers with sulfur va-cancy defects are firstly synthesized,which can not only provide more reaction active sites,but also enhance the electrical conductivity.BiCoS3-δ@Co1-x S composite fibers with heterostructure are also prepared by the in-situ growth of Co1-xS on BiCoS3-δ fibers.The heterojunction formed within BiCoS3-δ@Co1-xS can favor the charge transfer and enhance the surface reaction kinetics due to the build-in electric field effect.Simultaneously,the tightly contacted interface would improve their structural stability during cycle.Therefore,the heterostructured BiCoS3-3@Co1-x S fibers have the best electrochemical performance.Especially,the BiCoS3-δ@Co1-x S elec-trode maintains a high capacity of 413.5 mAh/g even after 3000 cycles at 1.0 A/g,displaying the excellent cyc-ling stability.
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