Improvement of the electrochemical performance of LiFePO 4 cathode by Y-doping
- PDF / 847,590 Bytes
- 8 Pages / 612 x 792 pts (letter) Page_size
- 96 Downloads / 201 Views
Prospective Article
Improvement of the electrochemical performance of LiFePO4 cathode by Y-doping F. Herrera, F. Fuenzalida, P. Marquez, and J. L. Gautier, Departamento de Química de los Materiales, Facultad de Química y Biología, Universidad de Santiago de Chile, Av. L.B.O’Higgins 3363, Santiago, Chile Address all correspondence to F. Herrera at [email protected] (Received 27 March 2017; accepted 4 August 2017)
Abstract LiFe1−xYxPO4 doped (d-LFP) with amounts of yttrium (0.01% < x < 5% w/w) show a remarkable effect on the electrochemical behavior. The dLPF samples were investigated on the Li extraction/insertion performance through charge/discharge and capacity–voltage curves. The best performance was attained with Y content of x = 1%. The materials were synthesized by a hydrothermal method and characterized by x-ray diffraction (XRD) and scanning electron microscopy–energy dispersive x-ray spectroscopy (SEM–EDX). The XRD studies showed that dLPF had the same monoclinic structure as the undoped material. The achieved electrode performance has been attributed to the addition of Y3+ ion by stabilizing the orthorhomic structure. The electrode resistance decreases through the Y-doping.
Introduction An important number of cathode materials such as mixed oxides, polyanions, and metallic complexes[1–3] have been studied in the scope to find new materials with better morphological, structural, and electrochemical properties to increase the performance of lithium batteries. A practical cathode must exhibit stable framework, relatively high-voltage, good lithium transport, and large theoretical capacity. The framework materials based on the phosphate polyanion have recently been identified as potential electroactive materials for lithium-ion batteries applications.[4–6] LiFePO4 is a good candidate because it presents low level of toxicity, safe to handle, low cost, high cycles number, highenergy density as well as a high thermal and structural stability. The LiFePO4 undergoes a complete insertion/extraction process without a significant change in the structure due to the strong P–O bond within the polyanion PO3− 4 , which provides a high stability for lithium ions migration. LiFePO4 also presents a relatively high theoretical capacity (170 mAh/g), which means it has been considered as an excellent candidate to be used in the manufacturing of lithium -ion rechargeable batteries. However, one of its greatest difficulties are: low conductivity and low transportation of Li-ions; resulting a poor C-rate. Many works have been carried out with the purpose of fixing this deficiency. They are focused on improving the synthesis conditions, adopting different methodologies as for example sol–gel,[4,7] hydrothermal,[4,8–10] solvothermal,[11] solid-state reaction,[4,12] carbothermal reduction,[4,13] among others.[4] Another strategy focuses on doping it with different cationic elements like Mn, Co, Ni, V,[14,15] among others.
Whittingham and co-workers[14] have studied the effect of V-doping in LiFePO4 at different temperatures.
Data Loading...
