Synthesis and electrochemical properties of porous LiV_3O_8 as cathode materials for lithium-ion batteries

摘要

In this paper, we report on the synthesis of porous LiV_3O_8 by using a tartaric acid-assisted sol-gel process and their enhanced electrochemical properties for reversible lithium storage. The crystal structure, morphology and pore texture of the as-synthesized samples are characterized by means of XRD, SEM, TEM/HRTEM and N_2 adsorption/desorption measurements. The results show that the tartaric acid plays a pore-making function and the calcination temperature is an important influential factor to the pore texture. In particular, the porous LiV_3O_8 calcined at 300 °C (LiV_3O_8-300) exhibits hierarchical porous structure with high surface area of 152.4m2 g~(-1). The electrochemical performance of the as-prepared porous LiV_3O_8 as cathode materials for lithium ion batteries is investigated by galvanostatic charge-discharge cycling and electrochemical impedance spectroscopy.The porous LiV_3O_8-300 displays a maximum discharge capacity of 320 mAh g~(-1) and remains 96.3% of its initial discharge capacity after 50 charge/discharge cycles at the current density of 40 mAg~(-1) due to the enhanced charge transfer kinetics with a low apparent activity energy of 35.2 kJ mol~(-1), suggesting its promising application as the cathode material of Li-ion batteries.