Improvement in Cycle Characteristics using PVP Based Direct Carbon Coating During High-Rate Charge and Discharge of Li[Ni0.93Co0.07]O2 Nanofibers: Application for Lithium Secondary Batteries

Abstract

In this study, carbon-coated porous nanofibers were prepared via electrospinning and the performance of Li[Ni 0.93 Co 0.07 ]O 2 (NC) synthesized by electrospinning (E-NC) and co-precipitation (C-NC) was compared. E-NC had a discharge capacity of 206 mAh g -1 at 0.1C (17 mA/g), which is 10% higher than that of C-NC (189.2 mAh g -1 ). E-NC shows a high-rate performance of 118.32 mAh g -1 (61.7%) at 5C (850 mA/g), which is 50% higher than that of C-NC (78.22 mAh g -1 = 45.7%). Charge transfer of the carbon-coated porous nanofiber E-NC decreased by 35% compared to C-NC after 20 cycles as observed using electrochemical impedance spectroscopy. The results of this study show that the nanofiber structure with carbon coating shortens the Li-ion diffusion path, improves electrical conductivity, resulting in excellent rate performance.