Bimetallic CoNiSe_(2)/C nanosphere anodes derived from Ni-Co-metal-organic framework precursor towards higher lithium storage capacity

摘要

Through uncomplicated carbonation process,a carbon-embedded CoNiSe_(2)/C nanosphere was synthesized from Ni-Co-MOF (metal-organic framework) precursor whose controllable structure and synergistic effect of bimetallic Ni/Co brought CoNiSe_(2)/C anodes with high specific surface area (172.79 m^(2)/g) and outstanding electrochemical performance.CoNiSe_(2)/C anodes obtained reversible discharge capacities of850.9 mAh/g at 0.1 A/g after cycling for 100 cycles.In addition,CoNiSe_(2)/C exhibits excellent cycle stability and reversibility in the rate test at a current density of 0.1–2.0 A/g.When the current density returns to 0.5 A/g for 150 cycles,its discharge ratio the capacity is 330.8 m Ah/g.Electrochemical impedance spectroscopy (EIS) tests suggested that CoNiSe_(2)/C anodes had a lower charge transfer impedance of 130.02Ωafter 30 cycles.In-situ X-ray diffraction (XRD) tests confirmed the alloying mechanism of CoNiSe_(2)/C which realized higher lithium storage capacity.This work affords substantial evidence for the extension of bimetallic selenides in secondary batteries,promoting the development of bimetallic selenides in anode materials for LIBs.