Effects of neodymium aliovalent substitution on the structure and electrochemical performance of LiFePO4

✍ Scribed by Xian Zhao; Xiaozhen Tang; Li Zhang; Minshou Zhao; Jing Zhai

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 1011 KB
• Volume: 55
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/j.electacta.2010.05.042

✦ Synopsis

a b s t r a c t LiFe 1-x Nd x PO 4 /C (x = 0-0.08) cathode material was synthesized using a solid-state reaction. The synthesis conditions were optimized by thermal analysis of the precursor and magnetic properties of LiFePO 4 /C. The structure and electrochemical performances of the material were studied using XRD, FE-SEM, EDS, electrochemical impedance spectroscopy and galvanostatic charge-discharge. The results show that a small amount of aliovalent Nd 3+ ion-dopant substitution on Fe 2+ ions can effectively reduce the particle size of LiFePO 4 /C. Cell parameters of LiFe 1-x Nd x PO 4 (x = 0.04-0.08) were calculated, and the results showed that LiFe 1-x Nd x PO 4 /C had the same olivine structure as LiFePO 4 . LiFe 0.4 Nd 0.6 PO 4 /C delivers the discharge capacity of 165.2 mAh g -1 at rate of 0.2 C and the capacity retention rate is 92.8% after 100 cycles. Charge-transfer resistance decreases with the addition of glucose and Nd 3+ ions. Poly(cyclotriphosphazene-co-4,4 -sulfonyldiphenol) (PZS) was synthesized and PZS nanorods were used as a carbon source to coat LiFePO 4 . All of the results show that aliovalent doping substitution of Fe in LiFePO 4 is well tolerated.