Spindle LiFePO₄ particles as cathode of lithium-ion batteries synthesized by solvothermal method with glucose as auxiliary reductant

The well-distribution spindle LiFePO₄ (LFP) nanoparticles as cathode of lithium secondary batteries were synthesized by a solvothermal reaction route at low temperature (180 °C) in which the ascorbic acid was used as reducing agent. In order to guarantee that the pH values of thermal systems were not affected too much and the reducibility of the system was enhanced at the same time, glucose was chosen as an auxiliary reductant in this reaction. The obtained powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and laser particle analyzer. The results show that the carbon-coated uniform spindle olivine LiFePO₄/C-glucose particles (glucose as auxiliary reductant, LFP/C-G) are prepared with the size 500–600 nm and without any impurity phases. Their electrochemical properties were evaluated by electrochemical impedance spectroscopy, cyclic voltammetry, and galvanostatic charge/discharge tests. LFP/C-G has a higher conductivity and better reversible capability than carbon-coated LFP (LFP/C). The highest discharge capacity of LFP/C-G is 161.3 mAh·g⁻¹ at 0.1C and 108.6 mAh·g⁻¹ at 5.0C, respectively. The results imply that the neat crystal nanostructure of LFP/C-G has excellent capacity retention and cycling stability. The adding of glucose is the key factor for the well-distribution and neat crystal structure of nanoparticles, thus the electrochemical performances of materials are improved.