L-Lysine-assisted solvothermal synthesis of hollow-like structure LiFePO4/C powders as cathode materials for Li-ion batteries

LiFePO4/C powders were synthesized by solvothermal method using L-Lysine as a surfactant for controlling over the particle size and shape. The effects of L-Lysine contents on the phase, structure, microstructure, and electrochemical properties were studied by X-ray diffractometry, scanning electron microscopy, infrared spectroscopy, galvanic charge/discharge, and electrochemical impedance spectroscopy methods. As the amount of L-Lysine increased, the large sheet-like morphology was transformed to the spherical particulate and hollow-like structure. The LiFePO4/C powder obtained by 50 mmol L-Lysine showed the highest specific capacity of 96 mAh g(-1) at 1C rate and high capacity retention of 95.6% following 650 cycles because of the low antisite defects and particulate morphology of LiFePO4. Moreover, the high rate capability of the LiFePO4/C powders was attributed to their small spherical particles and hollow-like structure, leading to the high electrochemical kinetics as investigated by electrochemical impedance spectroscopy. (C) 2021 The Author(s). Published by Elsevier B.V.

Automated summary

LiFePO4/C powders were synthesized using L-Lysine as a surfactant to control particle size and shape, with increasing L-Lysine content resulting in changes in morphology and performance. The LiFePO4/C powder obtained with 50 mmol L-Lysine exhibited the highest specific capacity and good cycling stability, attributed to low antisite defects and unique morphology. High rate capability was also observed due to the small spherical particles and hollow-like structure of the LiFePO4/C powders, leading to enhanced electrochemical kinetics.