Multicomponent-coated graphite composite anodes for low-temperature electrochemical energy storage
The rapid development of new energy technologies has demanded higher requirements for the application of lithium-ion batteries(LIBs)for operation at low temperatures.The poor surface dynamics of graphite anodes is one of the main issues limiting the low-temperature performance of LIBs.In this study,amorphous carbon/niobium oxide multicomponent-coated graphite composite materials(C/Nb-Gr)were synthesized using a liquid-phase method.The optimal C/Nb-Gr ratio was determined by adjusting the preparation method and coating ratio of multicomponent materials.The crystal structure,morphology,and elemental distribution of C/Nb-Gr were characterized using X-ray diffraction,scanning electron microscopy,transmission electron microscopy,and energy-dispersive X-ray spectroscopy.Furthermore,its electrochemical performance at high rates and low temperatures was evaluated using cyclic voltammetry,electrochemical impedance spectroscopy,and charge/discharge cycling.The graphite electrode coated with amorphous carbon/niobium oxide exhibited improved performance at high rates and low temperatures.When charged/discharged at a high current density of 5C at room temperature,C/Nb-Gr-10 demonstrated a reversible specific capacity of 156.18 mAh/g.Under low-temperature conditions(-20℃)at a current density of 0.1C,the discharge specific capacity of C/Nb-Gr-10 was 204.60 mAh/g,representing 55.7%of its room-temperature discharge specific capacity.
graphite anodessurface modificationlow-temperature energy storagelithium-ion batteries
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