Prominent enhancement of stability under high current density of LiFePO4-based multidimensional nanocarbon composite as cathode for lithium-ion batteries

[Display omitted] •LFP-based multidimensional nanocarbon composite as cathode exhibits improvement in electrochemical performance for LIBs.•Especially, graphene quantum dots play a key role in linking an interface between the LFP and carbon nanotubes during the cycling test.•Moreover, it contributes to the remarkable advancement under a high current density as well as stability in the cycling test. A facile method for synthesizing carbon-coated lithium iron phosphate (LiFePO4, LFP) and an LFP-based multidimensional nanocarbon composite to enhance the electrochemical performance of lithium-ion batteries is presented herein. Three types of cathode materials are prepared: carbon-coated LFP (LC), carbon-coated LFP with carbon nanotubes (LC@C), and carbon-coated LFP with carbon nanotubes/graphene quantum dots (LC@CG). The electrochemical performances of the LC-nanocarbon composites are compared, and both LC@C and LC@CG show improved electrochemical performance than LC. Compared with both the LC and LC@C electrodes, the LC@CG electrode exhibits the highest specific capacity of 107.1 mA h g−1 under 20C of current density, as well as higher capacities and greater stability over all measured current densities. Moreover, after 300 charge–discharge cycles, the LC@CG electrode exhibits the best stability than the LC and LC@C electrodes. This is attributable to the graphene quantum dots, which enhance the morphological stability of the LC@CG electrode during electrochemical measurements. Our findings suggest that LFP-nanocarbon composites are promising as cathode materials and highlight the potential of graphene quantum dots for improving the stability of cathodes.