The Root Cause of the Rate Performance Improvement After Metal Doping: A Case Study of LiFePO4

Bulletin of the Korean chemical society

SungBin Park¹  WonIl. Cho¹  Ho Jang¹  HoChul Shin¹  ChangKyoo Park¹  JiHun Park¹ 

关键词: LiFePO4;    Doping;    Rate performance;    XPS;    Binding energy;   

DOI  :  

学科分类：化学（综合）

来源: Korean Chemical Society

【 摘 要 】

This study investigates a root cause of the improved rate performance of LiFePO4 after metal doping to Fesites. This is because the metal doped LiFePO4/C maintains its initial capacity at higher C-rates than undoped one. Using LiFePO4/C and doped LiFe0.97M0.03PO4/C (M=Al3+, Cr3+, Zr4+), which are synthesized by a mechanochemical process followed by one-step heat treatment, the Li content before and after chemical delithiation in the LiFePO4/C and the binding energy are compared using atomic absorption spectroscopy (AAS) and X-ray photoelectron spectroscopy (XPS). The results from AAS and XPS indicate that the low Li content of the metal doped LiFePO4/C after chemical delithiation is attributed to the low binding energy induced by weak Li-O interactions. The improved capacity retention of the doped LiFePO4/C at high discharge rates is, therefore, achieved by relatively low binding energy between Li and O ions, which leads to fast Li diffusivity.

【 授权许可】

Unknown